Crabs: Anatomy, Habitat and Ecological Significance : Anatomy, Habitat and Ecological Significance [1 ed.] 9781619422407, 9781619422254

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Copyright © 2012. Nova Science Publishers, Incorporated. All rights reserved. Crabs: Anatomy, Habitat and Ecological Significance : Anatomy, Habitat and Ecological Significance, Nova Science Publishers,

Copyright © 2012. Nova Science Publishers, Incorporated. All rights reserved. Crabs: Anatomy, Habitat and Ecological Significance : Anatomy, Habitat and Ecological Significance, Nova Science

MARINE BIOLOGY

CRABS

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ANATOMY, HABITAT AND ECOLOGICAL SIGNIFICANCE

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Crabs: Anatomy, Habitat and Ecological Significance : Anatomy, Habitat and Ecological Significance, Nova Science

MARINE BIOLOGY

CRABS

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ANATOMY, HABITAT AND ECOLOGICAL SIGNIFICANCE

KUMIKO SARUWATARI AND

MIHARU NISHIMURA EDITORS

Nova Science Publishers, Inc. New York Crabs: Anatomy, Habitat and Ecological Significance : Anatomy, Habitat and Ecological Significance, Nova Science

Copyright © 2012 by Nova Science Publishers, Inc. All rights reserved. No part of this book may be reproduced, stored in a retrieval system or transmitted in any form or by any means: electronic, electrostatic, magnetic, tape, mechanical photocopying, recording or otherwise without the written permission of the Publisher. For permission to use material from this book please contact us: Telephone 631-231-7269; Fax 631-231-8175 Web Site: http://www.novapublishers.com

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The Publisher has taken reasonable care in the preparation of this book, but makes no expressed or implied warranty of any kind and assumes no responsibility for any errors or omissions. No liability is assumed for incidental or consequential damages in connection with or arising out of information contained in this book. The Publisher shall not be liable for any special, consequential, or exemplary damages resulting, in whole or in part, from the readers’ use of, or reliance upon, this material. Any parts of this book based on government reports are so indicated and copyright is claimed for those parts to the extent applicable to compilations of such works. Independent verification should be sought for any data, advice or recommendations contained in this book. In addition, no responsibility is assumed by the publisher for any injury and/or damage to persons or property arising from any methods, products, instructions, ideas or otherwise contained in this publication. This publication is designed to provide accurate and authoritative information with regard to the subject matter covered herein. It is sold with the clear understanding that the Publisher is not engaged in rendering legal or any other professional services. If legal or any other expert assistance is required, the services of a competent person should be sought. FROM A DECLARATION OF PARTICIPANTS JOINTLY ADOPTED BY A COMMITTEE OF THE AMERICAN BAR ASSOCIATION AND A COMMITTEE OF PUBLISHERS. Additional color graphics may be available in the e-book version of this book.

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Published by Nova Science Publishers, Inc. † New York Crabs: Anatomy, Habitat and Ecological Significance : Anatomy, Habitat and Ecological Significance, Nova Science

CONTENTS

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Preface

vii

Chapter 1

Different Species of Crabs and Viral Susceptibility Naraporn Somboonna

Chapter 2

Development of Trapping Gear and Methods for Swimming Crabs Miguel Vazquez Archdale

Chapter 3

Chapter 4

Chapter 5

Distribution and Habitat of Cold Water Crab Species on the Grand Bank of Newfoundland Darrell R. J. Mullowney, Elaine M. Hynick, Earl G. Dawe and William A. Coffey Neurosecretory Structure and Gonad Inhibiting Hormone in Eyestalk and the Physiology and Biochemistry of Spermatozoa in Eriocheir Sinensis Xianjiang Kang, Shumei Mu, Yanqin Li, Lijun Cheng, Kui Ma,Genliang Li, Qi Wang, Guirong Liu and Gang Cao Behavioral Differences in Fiddler Crabs, Uca Pugnax, from Contaminated and Reference Estuaries in New Jersey Lauren L. Bergey, Terry Glover and Judith S. Weis

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27

49

71

89

vi Chapter 6

Chapter 7

Contents Cellular Cadmium Transport in Gills and Hepatopancreas of Ucides Cordatus, a Mangrove Crab P. Ortega and F. P. Zanotto Crab Influences on the Export of Plant Detritus from Salt Marshes and Mangroves: A Review Jorge L. Gutiérrez

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Index

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123 147

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PREFACE This book presents topical research in the study of the anatomy, habitat and ecological significance of crabs. Topics discussed in this compilation include the different species of crabs and viral susceptibility; distribution and habitat of cold water crab species on the Grand Bank of Newfoundland; behavioral differences in fiddler crabs; cellular cadmium transport in gills and hepatopancreas of the mangrove crab and invasive swimming crabs. Chapter 1 - The chapter is divided into five main parts. The first part is an introduction to the general knowledge on species of crabs and the major viral diseases of aquatic species, including white spot disease, yellow head disease and Taura syndrome. The second part covered the white spot disease and its associated morbidity and mortality in different mud crab species, including Scylla serrata, Scylla paramamosain, Scylla olivacea and Scylla tranquebarica. Natural and experimental infection routes were also compared, and experimental infection route by intramuscular injection was found to be the most effective for introducing the white spot syndrome virus infection. Under experimental conditions, different doses and single- versus multipleinjection methods were considered. Together, the crabs were susceptible to the white spot disease in species-, dose- and history-dependent manners. Yet, more researches are needed, as many researches with no specified dose information might render the interpretation inaccurate. The infected crabs, either symptomatic or asymptomatic, were capable of disease transmission, representing the carriers or reservoir hosts of the disease. Another part of the chapter described the variations in research approaches among laboratories that might affect the diverse research results. The fourth part indicated possible threats by the asymptomatic and symptomatic crabs to other species and the ecosystem. Prior to the conclusion of the chapter, the fifth part illustrated

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Kumiko Saruwatari and Miharu Nishimura

advantages of better understanding of the susceptibility of each crab species to the viral infection. The knowledge benefits not only scientists but also farmers, marketing and governmental management. Chapter 2 - When looking at the capture process of traps targeting aquatic organisms, there are factors which fishers can control and others which they cannot. Examples of those beyond their control are the physical parameters of the fishing ground, such as depth, water temperature or type of substrate; and the physiological condition of the target organism, such as hunger state or molting stage. Factors that can be controlled include the attractiveness of the bait used and the design of the fishing gear employed. Through history, traps have proven to be an effective tool for harvesting crustaceans. They are small, simple, cheap and can be carried in large numbers stacked onboard small boats. Traps are qualified as passive fishing gear because they are dropped on the seafloor and left unattended for hours or days. The target organisms are commonly lured towards them using bait, and it is the attractiveness of this bait that is most important and will determine the quantity and quality of the catch. Improving the luring methods and the attractiveness of bait for crabs will be discussed, beginning with the determination of the most attractive substances contained in them, which consist mostly of amino acids and sugars. Based on these findings, a novel fishing method that employs a bait combination of fish and sugarcane will be introduced, which has resulted in a great increase in the crab catch. Following bait, second in importance is the design of the fishing gear. After the target animal has been lured towards and is in contact with a trap, the design and the type of entrance will determine the number of crabs that will enter and, consequently, the success of the fishing operation. In order to find the reasons why some trap designs and entrance types are more efficient at catching crabs rather than others it is insufficient to compare the catches of different gear designs during fishing trials. It is essential to make observations on the behavior of crabs around the traps, and this can be accomplished by placing both baited traps and crabs on the seafloor or inside large tanks, and recording their interactions by video. Improvements on trap design can be made after observing how crabs behave after they reach the trap and by determining the difficulties they encounter finding the entrances. Observations on crab behavior around different trap designs showed that they search larger areas around traps with oval bases than those with rectangular ones, and this gives them more access to the trap entrances. Open funnel entrances allowed entry of most crabs contacting the traps and were superior to tight slit entrances, which only permitted ingress of a smaller number because the netting material entangled with the spines of the crabs and

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Preface

ix

many gave up after several attempts. Traps fitted with open entrances also tended to catch fewer non-target animals and permitted the escape of animals, which resulted in them being more environmentally friendly by reducing the non-target catch and the negative impact that lost gear causes on the aquatic resources by ghost fishing. Chapter 3 - New technologies in ocean mapping have allowed for improved classification of bottom substrate and three-dimensional views of the ocean floor. The Department of Fisheries and Oceans Canada (DFO) has been opportunistically collecting three-dimensional bottom classification data on research surveys along the Newfoundland and Labrador (NL) continental shelf for 17 years, with the Grand Bank off Newfoundland’s southeast coast presently most comprehensively mapped. The Grand Bank is comprised of diverse habitats, including a cold thermal regime across the shallow northern portion which is dominated by hard bottom substrates, and warmer regimes on the southern portion and deeper slope edges which are characterized by a variety of bottom substrate types. Several species of crabs inhabit the Grand Bank ecosystem, ranging from large, commercially important and extensively studied species such as the Snow Crab (Chionoecetes opilio), to small species such as Hermit Crabs (Pagurus spp.) for which little is known. In this chapter, the authors utilize data from spring and fall multi-species trawl surveys routinely conducted across the Grand Bank from 1995-2010 to investigate the distribution and habitat preferences of all crab species inhabiting the region. The authors examine the distribution of each species in relation to bathymetry and thermal regime, and for the first time incorporate bottom classification information to examine the habitat preferences of each species in a near-virtual fashion. Chapter 4 - In this charpter, Eriocheir sinensis was studied on the characteristic of the eyestalk and spermatozoa. 5 types of the neuroendocrine cells in eyestalks of the crab were distinguished by optical microscope. They distributed on the medulla interns and medulla treminalia of the optic ganglia. In the sinus gland (SG), 5 types of neurosecretory terminals were identified via transmission electron microscope. By reverse-phase high-performance liquid chromatography (RP-HPLC), GIH were obtained. Measured by MOLDI-TOFMS after further purification, its molecular weight is 6.8 ku. After immune localization of GIH in crab’s optic ganglia, we found GIH always located in type 1 and type 4 cells of optic ganglia. 12 different kinds of sperm membrane proteins from the mature spermatozoa of E. sinensis were analyzed by SDSPAGE. Their molecular weights are between 21.6 ku and 75.5 ku, which indicate the sperm membrane proteins of E. sinensis are a set of proteins with

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low molecular weights. Gomori reaction and electron microscopy were used for localization of acid phosphatase during spermiogenesis in E. sinernsis. The results showed that: Acid phosphatase was synthesized in the endoplasmic reticulum in the early spermatids. The acid phosphatase was found gradually in nucleus, the membrane of acrosomal vesicle, the cytoplasmic region and the acrosomal tubule. And then the reaction product particles became thicker during the spermiogenesis. In the mature spermatozoa, acid phosphatase was localized in the percutor organ slightly, but it was massive and compact in the acrosomal tubule. With E. sinensis as the experimental material, this chapter is about extraction and antisera preparation of the compositions of spermic membrane proteins before acrosome reaction (SBAs) and spermic membrane proteins during third phase of acrosome reaction (SDAs) and PRAs, and those compositions are compared and analysed by sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE) to conjecture their effects on acrosome reaction of spermatozoa, as well as the effects of hydrophilic swelling, spermic density in buffer, trypsin, Ca2+, temperature, time of cryopreservation, compositions of cryopreservation buffers and three kinds of antisera mentioned above on acrosome reaction by the means of statistcs and microscope. The authors then built up three kinds of novel and simple methods inducing spermatozoa acrosome reaction (freezing method, trypsin-Ca2+ method and antisera method). Chapter 5 - Studies on a variety of organisms have shown reduced activity levels and reduced prey capture or feeding in polluted environments compared to animals from cleaner sites. Laboratory and field studies were performed on fiddler crabs (Uca pugnax) from a polluted vs. reference environment in New Jersey. Based on prior studies, the authors hypothesized that crabs from the contaminated site would eat less and would be less active than those from the reference site, and that this would have deleterious effects. Overall, the crabs from the contaminated site, Piles Creek (PC), tended to spend more time inactive on the surface or in their burrows compared with crabs from Tuckerton (TK), the reference site. TK crabs generally spent more time active and feeding. While reduced feeding suggests that growth might be reduced in the PC crabs, a previous study found that they tend to be larger, not smaller at PC, but have lower density. Differences in levels of available nutrients may play a role in behavioral differences. Also, spending more time inactive in their burrows would reduce energy expenditures and could also make them less likely to be captured by a predator. In an experiment in which crabs from both populations were exposed to a blue crab (Callinectes sapidus) predator, PC crabs were less likely to be captured, which may be related to their greater

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Preface

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tendency to stay in burrows. Thus, despite having reduced activity levels and reduced feeding, crabs at PC did not appear to suffer adverse ecological consequences. Chapter 6 - Ucides cordatus is a mangrove crab, and has a very important role in human food consumption. Mangrove areas can be contaminated with heavy metals, like cadmium (Cd), through waste and disposal of batteries from industries. This metal reaches the animal through its gills, when is dissolved in the water, or through its hepatopancreas, from consumption of contaminated food. Because this metal does not have any physiological role for the animal, small concentrations can be extremely toxic. It is not known how cadmium enters the cells, but, because it is a divalent metal, it could enter cells together with calcium, using its plasma membrane channels to penetrate the cells. Therefore, the objective of the work was to characterize the kinetics of Cd transport. For this, the gill cells were separated by enzymatic dissociation, and the hepatopancreatic cells were dissociated by magnetic stirring, then, the cells were separated by sucrose gradient, and labeled with Fluo 3 AM. After that, the kinetics of Cd transport was characterized in the spectrofluorimeter, with addition of successive CdSO4 concentrations (0.5, 1.0 and 1.5 µM), respectively. Results showed a sigmoidal curve for Cd transport, suggesting that others ions, like calcium, for example, can participate in the transport of Cd. Chapter 7 - While crabs occur in perhaps most salt-marshes and mangroves worldwide, they are rarely considered in studies dealing with tidal fluxes of plant detritus from these coastal wetlands to adjacent waters. However, crabs can affect the production, availability and tidal transport of plant detritus in a variety of ways. This includes controls via both assimilatory-dissimilatory mechanisms (e.g., herbivory, detritivory, seed and propagule consumption) and non assimilatory, non dissimilatory environmenttal modification (i.e., physical ecosystem engineering; e.g., sediment oxygenation via burrows, detritus excavation and burial, detritus trapping into burrows). Given the high densities and activity rates shown by many crab species, their effects on the export of plant detritus are expected to be important relative to overall marsh production. Therefore, the predictive capacity of models dealing with detritus export by salt marshes and mangroves is likely to be enhanced by considering crab influences.

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In: Crabs: Anatomy, Habitat, Editors: K. Saruwatari, M. Nishimura

ISBN: 978-1-61942-225-4 © 2012 Nova Science Publishers, Inc.

Chapter 1

DIFFERENT SPECIES OF CRABS AND VIRAL SUSCEPTIBILITY Naraporn Somboonna

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Department of Microbiology, Faculty of Science, Chulalongkorn University, Bangkok, Thailand

ABSTRACT The chapter is divided into five main parts. The first part is an introduction to the general knowledge on species of crabs and the major viral diseases of aquatic species, including white spot disease, yellow head disease and Taura syndrome. The second part covered the white spot disease and its associated morbidity and mortality in different mud crab species, including Scylla serrata, Scylla paramamosain, Scylla olivacea and Scylla tranquebarica. Natural and experimental infection routes were also compared, and experimental infection route by intramuscular injection was found to be the most effective for introducing the white spot syndrome virus infection. Under experimental conditions, different doses and single- versus multiple- injection methods were considered. Together, the crabs were susceptible to the white spot disease in species-, dose- and history-dependent manners. Yet, more researches are needed, as many researches with no specified dose information might render the interpretation inaccurate. The infected crabs, either symptomatic or asymptomatic, were capable of disease transmission, representing the carriers or reservoir hosts of the disease. Another part of the chapter described the variations in research approaches among laboratories that

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2

Naraporn Somboonna might affect the diverse research results. The fourth part indicated possible threats by the asymptomatic and symptomatic crabs to other species and the ecosystem. Prior to the conclusion of the chapter, the fifth part illustrated advantages of better understanding of the susceptibility of each crab species to the viral infection. The knowledge benefits not only scientists but also farmers, marketing and governmental management.

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1. INTRODUCTION Annually, the European Union or EU imports several megatons of crabs from several production regions, particularly Asian countries. The quantity of imported live and frozen crustaceans had increased 45% since 1999 [Stentiford et al. 2009]. Although most viral diseases of aquatic species were reported to cause no clinical symptoms in humans to date, it is vital for the EU to examine all the imported crabs for the major viral diseases such as white spot disease and yellow head disease. Especially, if the crabs were imported alive, the crabs may be used as broodstock in crab acquaculture or be accidentally released to the nature, allowing the transmission of the disease and the possibility of the disease outbreak. Infected crabs, with or without clinical disease, could serve as the carriers of the pathogenic viruses, and transmit the viruses to other susceptible hosts [Rajendran et al. 1999, Stentiford et al. 2009]. Susceptible species are defined by an ability of a species to be infected and carry the disease-causing agent, despite showing no clinical symptoms [Stentiford et al. 2009]. Hence, crabs are generally accepted as susceptible to many viral diseases, although they are relatively disease-resistant because they could be infected and transmit the pathogenic viruses to the others. In 2008, the European law, EC Council Directive 2006/88/EC, declared three crustacean diseases to be aware of, which were white spot disease or WSD caused by white spot syndrome virus (WSSV), yellow head disease or YHD caused by yellow head virus (YHV), and Taura syndrome or TS caused by Taura syndrome virus (TSV) [Stentiford et al. 2009]. This book chapter thereby discussed the similarity and dissimilarity among various crab species, particularly mud crabs owing to the greater number of researches available, to WSSV infection. The chapter covered the different methods of viral challenge, as well as the different infectious dose amounts. Nevertheless, as the researches on this field remain restricted, the chapter included discussions on any discrepancies on research approaches, such as species of crabs, doses of infection, methods of infections and days of

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Different Species of Crabs and Viral Susceptibility

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observation, and described the possible effects of these differences on the research results. While over 4,500 species of crabs have been identified, mud crabs of the genus Scylla are most economically important in commercial fisheries and aquaculture markets [Rajendran et al. 1999, Stentiford et al. 2009]. Ecologically, mud crabs are the main species of the marine food webs, serving both as consumers of aquatic animals and plants, and as preys to many birds, fish and mammals. Mud crabs exhibit a relatively high resistance to many viral disease developments, so they are not recognized by the farmers and thereby often represented asymptomatic carriers or reservoir hosts to the other species and the ecosystem. The infecting viruses inside asymptomatic or symptomatic crabs, alive or moribund crabs, usually remain infectious to the others [Kanchanaphun et al. 1998, Supamattaya et al. 1998, Rajendran et al. 1999, Somboonna et al. 2010]. S. serrata is generally the most distributed mud crab species. The species was found abundant in the Pacific and Indian oceans [Fushimi and Watanabe 1999, Keenan 1999, Imai et al. 2004, Webley and Connolly 2007, Somboonna et al. 2010, Liu et al. 2011]. S. serrata is often found in Australia (Gulf of Carpentaria, Moreton Bay and Northern Territory), east African coast (South Africa, Mauritius and Yemen) and north Asia (Taiwan, Japan and Philippines), and is less often found in Thailand, Malaysia and Vietnam. S. serrata is commercially important because of its huge size and fast growth rate [Fortes 1999]. In China, S. serrata is the main cultured marine crab species. China produces about 108,500 tons per year, accounting for 88% of total cultured crabs in the world crab market [Liu et al. 2011]. The morphology of S. serrata comprises a characteristic mottled green to dark brown carapace color, except around the lines on the gastric, anterolateral teeth and branchial regions. The four frontal lobe teeth are bluntly pointed, and equally spaced from one another. The frontal lobe teeth are also of roughly equal size and prominence. Nine spines on the antero-lateral carapace are sharp and of equal size, except the last pair that has the smallest size [Fushimi and Watanabe 1999]. Carpus and propodus have obvious pairs of large spines. The polygonal pattern is present in all appendages of chelipeds and legs [Türkay and Sakai 1995, Davie 1998, Keenan 1999]. S. paramamosain is another species of significance in local and international markets. S. paramamosain is regarded as a variant of S. serrata due to their related sequence similarity [Imai et al. 2004]. The species is often found in Vietnam, Hong Kong, Indonesia and Philippine [Keenan 1999, Christensen 2004].

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S. paramamosain is distinguished by its greyish green carapace color [Sugama and Hutapea 1999]. The frontal lobe teeth are moderately highpointed and triangular with straight margins and angular interspaces. Spines are large and obvious in the propodus, and are reduced and not obvious in the carpus. Chelipeds and legs show a weak or absent polygonal pattern [Davie 1999, Keenan 1999]. S. olivacea is widely distributed in Southeast Asia. The species is generally recognized as the most abundant and commercially important for most of Thailand's fishery regions [Moser et al. 2005]. S. olivacea is also prevailing in Indonesia, Singapore, Taiwan and Vietnam [Cholik and Hanafi 1991, Keenan 1999]. S. olivacea has a characteristic purple-brown carapace color [Fortes 1999]. Other distinct morphological features include low and rounded frontal lobe teeth with shallow interspaces. Antero-lateral teeth are broad and are outer convex. Spines are reduced in size in the propodus, and are almost absent in the carpus. Polygonal patterning in chelipeds, legs, and abdomen are absent [Davie 1999, Keenan 1999]. Scylla tranquebarica is less widespread than S. serrata, S. paramamosain and S. olivacea. S. tranquebarica is found to be more common in Philippine crab markets [Keenan 1999, Fortes 1999]. Similar to S. paramamosain, S. tranquebarica has a grayish-green color and a broad antero-lateral carapace. The frontal lobe teeth are moderately high and blunted with rounded interspaces. The lateral spines are sharp. Pairs of large spines are obvious on the carpus and propodus. Polygonal patterning is weak on chelipeds and the first two pairs of legs, but is strong for the last two pairs of walking legs [Davie 1999, Fushimi and Watanabe 1999, Keenan 1999].

2. THREE MAJOR VIRAL DISEASES OF CRUSTACEANS 2.1. White Spot Disease The white spot disease (WSD) was first discovered in China and Taipei in 1992. WSD spread throughout Asia and became pandemic globally in 1999 [Flegel 1997, Wang et al. 2000, Stentiford et al. 2009]. Currently, WSD accounts for the most threatening infectious agent for global shrimp farming. The disease has caused a massive shrimp mortality yearly, and has a cumulative loss of exceeding 10 billion US dollars since 1993 [Stentiford et al.

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Different Species of Crabs and Viral Susceptibility

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2009]. The frequency of WSD is high in tropical regions and has peaks from June to early July and from late September to early November [Hossain et al. 2001, Stentiford et al. 2009, Liu et al. 2011]. WSD is caused by WSSV. The disease and the virus are named following the clinical sign of white spots in the exoskeletons of the hosts with the disease. White spots represent the accumulated calcium on the inner surface of the cuticle. Other symptoms include weariness, reduced food uptake and loose cuticle [Flegel 1997, Wang et al. 1999, Escobedo-Bonilla et al. 2008]. WSSV is a double-strand DNA virus in the genus Whispovirus, family Nimaviridae. WSSV is rod-shaped of approximately 70-167  210-380 nm in size, and has a tail-like appendage at one end. Ultrastructural studies of the infected cells revealed the viruses residing in inclusions in the nuclei of target organs and tissues. WSD generally results in 100% mortality in shrimps [Mayo 2002, Escobedo-Bonilla et al. 2008, Stentiford et al. 2009]. For crabs, crayfish and lobsters, the percent morbidity and mortality varied depending on the host species and the specific strains of the WSSV [Escobedo-Bonilla et al. 2008, Chen et al. 2000, Sahul-Hameed et al. 2000, Hossain et al. 2001, Rodríguez et al. 2003, Yoganandhan et al. 2003, Marks et al. 2004]. WSD can be transmitted horizontally and vertically. The horizontal transmission of WSSV is often by consumption of infected tissues and by water-borne routes. The vertical transmission was demonstrated by eggassociated mechanism [Lo et al. 1997, Rajendran et al. 1999, Stentiford et al. 2009]. The transmission can occur among healthy, dead and moribund aquatic species, all of which can serve as carriers, reservoirs or amplifiers of WSSV [Lo et al. 1997, Lo and Kou 1998]. Recently, a total of 98 host species were reported susceptible to WSSV infection, and the Directive 2006/88/EC by the European Council listed all decapods, which comprised of over 20,000 species, as susceptible to WSSV [Stentiford et al. 2009]. The reason was because the scientific data suggested the very broad host range for the WSSV than YHV and TSV. Many marine and freshwater decapods were successfully infected by WSSV, naturally and artificially, and the infected species were able to transmit the diseases. Nevertheless, since not every crustacean species has been tested for the WSSV susceptibility, the Directive 2006/88/EC statement might be overestimated [Escobedo-Bonilla et al. 2008, Stentiford et al. 2009]. Consequently, this book chapter aims to review degrees of WSSV susceptibility to infection and to disease development among mud crab species.

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2.1.1. WSD in Scylla Species 2.1.1.1. WSD in Scylla serrata During 2006-2008, to determine the prevalence of WSSV in nature, Liu et al. [2011] collected 313 morbid mud crabs with signs of weakness and lethargy from Zhejiang Province of China. The prevalence of WSSV among the diseased mud crabs was detected by polymerase chain reaction (PCR) using specific WSSV primers, and was found to be relatively low in 2006 (14.63%) and high in 2007 (41.52%) and 2008 (31.68%). The mean prevalence of WSSV in morbid mud crabs in this region is thereby approximately 34.82% (109 of 313 crabs). This finding supported the susceptibility of S. serrata to infection and its threats as WSSV carriers. Under experimental conditions, most S. serrata being injected intramuscularly with a dose of WSSV that was lethal for shrimps, or orally fed with WSD tissues, showed no clinical symptoms and no histopathology [Kanchanaphum et al. 1998, Rajendran et al. 1999, Flegel 2007]. Rajendran et al. [1999] also replicated natural infection routes by one-day oral feeding and seven-day oral feeding, and compared with experimental infection route by intramuscular injection, using 10 S. serrata per group. The results indicated that the infection by injection was more effective than daily oral feeding for seven days and for one day, respectively. Injection and seven-day oral feeding caused 1% of S. serrata to die, whereas single-day oral feeding caused no mortality in 3 days. At 30 days, accumulated total of 30%, 20% and 10% of S. serrata died following WSSV injection, seven-day oral feeding, and one-day oral feeding, in orderly [Rajecdran et al. 1999]. No white spots were observed on the carapace but histopathological and bioassay analyses of the gills and stomach tissues of the infected crabs were positive. The gills and stomach tissues of the infected S. serrata contained infectious particles, because shrimps that were fed with these tissues exhibited clinical symptoms and were dead within 2-3 days [Rajendran et al. 1999]. Hence, the data also supported the infection ability of WSSV to S. serrata, albeit asymptomatic infection, and the ability of the crabs as the carriers or the reservoirs for WSSV transmission. Unfortunately, no WSSV doses that were inoculated for each tested group were specified [Rajendran et al. 1999], complicating comparative data analyses among various publications. Within the same S. serrata species, Liu et al. [2011] found morbidity and mortality by WSSV injection to be dose-dependent. The percentages of morbidity and mortality were correlated with the challenge doses. At low doses of 3.1103 and 3.1104 WSSV copies/g, only 33.3% (6 of 18) and

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44.4% (8 of 18) of the crabs died by 6 days post-injection. The percent cumulative mortalities of the two groups at day 10 were 38.9% (7 of 18) and 66.7% (12 of 18), suggesting the lethal dose 50 to be around these inoculation concentrations. At high doses of 3.11055 and 3.1106 WSSV copies/g, every crab (100%) died by 6 days. In summary, the lethal dose 50, LD50, in S. serrata was calculated to be 7.34103 copies per gram of crab weight. Histopathological analyses confirmed the morbidity and mortality of the diseased crabs due to WSSV, and the diseased crabs showed WSSV mainly in gills, subcuticular epithelia, heart, intestine and stomach [Liu et al. 2011].

2.1.1.2. WSD in Scylla paramamosain No WSSV susceptibility test by natural infection routes has been done in S. paramamosain. For experimental challenge, multiple but single dose injections had been tested. Figure I shows the mortality of individual S. paramamosain after multiple dose challenges and days by Somboonna et al [2010]. At day 0, nine S. paramamosain were each initially injected intramuscularly with 1104 WSSV copies/g of crab. 22.22% died within 10 days, while 77.78% of the crabs survived for 14 days. Comparing to the single WSSV challenge reported by Liu et al. [2011], S. paramamosain were found to be relatively more resistant to mortality by WSSV than S. serrata. Then, increasing doses of 1105, 5105, 1106 and ending with 5106 WSSV copies/g at day 56 were injected on each crab in the tested group every 14 days. The crabs in the control group were challenged by injection of sterile saline buffer using the same injection manners and equal injection volume as the tested crabs. The crabs were observed for 50 days following the final challenge dose, leading to a total of 106 days for the entire experiment. Of 7 S. paramamosain left after the initial challenge, no additional mortality (22.22% cumulative mortality) was found for 14 days following the 1105 copies/g challenge. At 5105 WSSV copies/g, 3 crabs died, accounting for the cumulative mortality of 55.56%, within 12 days. The calculated LD50 was thereby 3.89105 copies/g for S. paramamosain that had a history of low WSSV dose injection. Interestingly, no additional mortality was found for 14 days after the fourth challenge of 1106 WSSV copies/g on day 42. At the highest dose of 5106 WSSV copies/g, all remaining crabs survived for 17 days.

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Figure I. Survival of S. paramamosain in days after multiple WSSV challenges. The numbers at the top represent the copy numbers of the WSSV injected at the corresponding days. Individual S. paramamosain is named by initials Sp, followed by random numbers. The figure was taken with permission from Somboonna et al. [2010].

Two crabs died on day 17, accounting for 77.78% (7 of 9) cumulative mortality. On the other hand, the rests of S. paramamosain (22.22%) survived at 5106 WSSV copies/g dose, and were active through the end of the experiment on day 106. Comparing between 66.7% cumulative mortality in S. serrata at 3.1104 WSSV copies/g [Liu et al. 2011] and 22.22% cumulative mortality in S. paramamosain at the initial challenge at 1104 WSSV copies/g, the data highlighted the greater resistance to WSSV in S. paramamosain. In addition, the data by S. serrata and S. paramamosain following 3.1105 and above WSSV copies/g doses [Liu et al. 2011] showing the lower percent cumulative mortality and the higher LD50 in S. paramamosain, highlighted perhaps an advantage of pre-exposure to low doses of WSSV. The calculated mean time to death for those S. paramamosain that died was 37.0  27.5 days. The Kaplan-Meier survival probability was 0.44 for 63 days and 0.22 for 70 and 106 days following the initial challenge [Somboonna et al. 2010]. All S. paramamosain that died with doses of 5105 copies/g or more showed positive histopathology for WSSV lesions and severe WSSV infection. Detection and quantification of WSSV in hemocytes were measured using commercial

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IQ2000™ WSSV Detection and Prevention System (Farming IntelliGene Technology Corporation, Taipei, Taiwan) and the real-time PCR using established primers [Somboonna et al. 2010]. Consequently, the susceptibility to WSD in S. paramamosain seemed to be dose- and history-dependent. As displayed in Figure I, the crabs that were pre-exposed to low doses of WSSV appeared to have more chance of survival at the high doses of WSSV. In nature, the multiple-dose challenge might resemble oral feeding and bathing of non-lethal doses of WSSV. Indeed, penaeid shrimps being injected with hemolymph containing WSSV and immune contents from the survived WSSV-infected crabs showed partial WSD protection compared with hemolymph from the mock-infected crabs of the same species [Somboonna et al., data unpublished]. Yet, although invertebrates like crabs should contain no acquired immunity, the multiple-dose challenge results highlighted the ability of the crabs to somewhat obtain a long-term or memorized immunity based on the prior WSSV exposure to combat the WSSV infection at the latter time.

2.1.1.3. WSD in Scylla olivacea Following the experimental WSSV challenge by a single injection method, the data for S. serrata by Liu et al. [2011] indicated a slightly less degree of disease tolerance than S. olivacea [Somboonna et al. 2010]. A dose of 1105 WSSV copies/g caused 44% mortality in S. olivacea in 7 days. At the higher dose of 1106 WSSV copies/g, S. olivacea exhibited the cumulative percent mortality at 3, 4, 5 and 7 days to be 46%, 77%, 92% and 100%, respectively. None of the mock-injected crabs, representing controls of the experiment, died [Somboonna et al. 2010]. For the multiple-dose challenge using intramuscular injection methods (Figure II), Somboonna et al. [2010] began day 0 with 1104 WSSV copies/g of crab, followed every 14 days by increasing doses of 1105, 5105, 1106 and ending with 5106 WSSV copies/g at day 56. The crabs were observed for 50 days after the final challenge, leading to a total of 106 days for the entire challenge experiment. Of the 11 S. olivacea in the tested group, no mortality was found at 14 days after the initial challenge of 1104 WSSV copies/g. At 1105 WSSV copies/g, 18.18% (2 of 11) cumulative mortality was found on day 14 post injection. At 5105 WSSV copies/g, 1 crab died on day 3, and no

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more crab died, resulting in the accumulated percent mortality of 27.27 (3 of 11 crabs) for 14 days post-infection.

Figure II. Survival of S. olivacea in days after multiple WSSV challenges. The numbers at the top represent the copy numbers of the WSSV injected at the corresponding days. Individual S. olivacea is named by initials Sp, followed by random numbers. The figure was taken with permission from Somboonna et al. [2010].

At 1106 WSSV copies/g, no mortality was found throughout 14 days of the observation period. Finally, at the highest dose of 5106 WSSV copies/g, 36.36% (4 of 11), 90.91% (10 of 11) and 100% (11 of 11) accumulated mortality was found by days 7, 14 and 17 post-infection, respectively. The LD50 of S. olivacea following the multiple-dose challenge was thereby 5106 WSSV copies/g, even greater than those of S. serrata and S. paramamosain. The calculated mean time to death of S. olivacea was 55.9  20.6 days, which was not statistically different from the mean time to death of S. paramamosain (p = 0.11). The Kaplan-Meier survival probability was 0.63 for 63 days and 0 for 70 days [Somboonna et al. 2010]. Unlike the data of S. paramamosain, the data in Figure II might be classified into two main groups: one group that died after the low dose of 1105 copies/g, and the other group that died after the highest dose of 5106 copies/g.

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These resulted in the higher LD50, and yet no survival at the highest dose. Except the first two crabs that died at days 21 (7 days after 1105 WSSV copies/g), all WSSV-infected crabs showed severe WSSV infection using the commercial kit and the real-time PCR. The mean was 6.5108 WSSV copies per 100 ng of total DNA, and 100 ng of DNA was about 0.15 mg of a fresh muscle tissue. Thus, the mean of WSSV was 43.33 ng DNA per gram of crab tissue. Comparing between single-dose and multiple-dose challenges, more number of crabs survived at the high-dose challenge when they were preexposed to the low-dose WSSV challenge. This supported the benefit of lowdose challenges. In nature, the low-dose challenge could resemble oral feeding or bathing though WSSV-contaminated water or feeds. Together, the susceptibility to WSD in S. olivacea seemed to be relatively lower than S. serrata and S. paramamosain. Similar to S. paramamosain, the WSD susceptibility was found to be dose- and history-dependent. S. olivacea that were pre-exposed to low-dose WSSV had the greater survival rate that those that were not.

2.1.2. WSD in the Other Crab Species In parallel with the comparative studies of WSD sensitivity between natural infection routes by single and seven-day oral feeding, and experimental infection route by intramuscular injection in S. serrata, Rajendran et al. [1999] also performed identical experiments on the mud crabs S. tranquebarica and the 2 other crabs in the genera Metapograpsus species and Sesarma species. The results also indicated the degrees of WSD susceptibility to be speciesdependent, because different crab species exhibit various resistances to WSD and mortality rates. Similar to that observed in S. serrata, the infection by intramuscular injection method was more effective than the daily oral feeding for seven days and for one day, respectively [Rajendran et al. 1999]. WSSV injection and seven-day oral feeding caused 20% and 10% cumulative mortality in S. tranquebarica in 30 days, respectively. Comparing to the data of S. serrata, the mortality rate was found to be slightly lower in S. tranquebarica. On the other hand, only single oral feeding was capable of causing 100% mortality in Metapograpsus sp. and Sesarma sp. within 30 days. All the tested crabs were positive for histopathology and bioassay analyses, and the gills and stomach tissues of the infected crabs were infective [Rajendran et al. 1999].

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2.2. Yellow Head Disease The yellow head disease (YHD) was first reported as baculovirus-like in black tiger shrimps Penaeus monodon in Thailand in 1990 [Boonyaratpalin et al. 1993, Chantanachookin et al. 1993]. Baculoviruses were DNA viruses and should reside in the nuclei of the host cells. However, studies by Lu et al. [1994] and Wongteerasupaya et al. [1995a, 1995b] showed that YHV inhabited the cytoplasm of the infected cells, revealing the virus instead as an RNA virus. The disease was later spread throughout Asia. During 1995, outbreaks of YHD were documented in Australia and Thailand [Stentiford et al. 2009]. YHD is caused by YHV. The disease and the virus are named following the clinical sign of yellow discoloration or bleached appearance on the dorsal cephalothorax of the diseased shrimps [Boonyaratpalin et al. 1993, Chantanachookin et al. 1993]. YHV is a positive-sense ssRNA in the genus Okavirus, family Roniviridae [Cowley and Walker 2002, Mayo 2002, Jitrapakdee et al. 2003]. YHV has a rod shape with envelope of about 40  170 nm in size. YHV is viable in seawater for up to 72 hours, and could be inactivated by heating at 60C for 15 minutes, 30 parts per million (ppm) of chlorine or calcium hypochlorite, and 250 ppm of iodine compound for 30 minutes [Flegel 1997]. Sequencing of the open reading frame (ORF) genes ORF1a and ORF1b allowed classification of YHV with six genotypic variants to date [Cowley et al. 2000; Walker et al. 2001, Sittidilokratna et al. 2002, Soowannayan et al. 2003, Wijegoonawardane et al. 2004]. The original genotypic variant was from Thailand, and differed from that from Australia by about 15% of the nucleic acid sequences. The third variant was collected from Thailand and Vietnam, and differed from the first two variants. The horizontal transmission of YHV by consumption of infected tissues and infected extracts, co-habitation with infected crustaceans, and by other water-borne routes was reported [Flegel 1997, Stentiford et al. 2009]. The overall prevalence of YHV in wild and cultured, healthy shrimps was high (50-100%), and genotypes were found varied by location. The high prevalence inferred the ease in YHV transmission and epidemics [Stentiford et al. 2009]. In addition, Wijegoonawardane and colleges [2004] demonstrated the evidence of genetic recombination among YHV genotypes. Presently, unlike WSSV, the Directive 2006/88/EC does not list every crustacean species as susceptible to the YHV infection. The species that were listed as susceptible to YHV were: Gulf brown shrimp Penaeus aztecus, Gulf pink shrimp Penaeus duorarum, Kuruma prawn Penaeus japonicus, black

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tiger shrimp P. monodon, Gulf white shrimp Penaeus setiferus, Pacific blue shrimp Penaeus stylirostris and Pacific white shrimp P. vannamei [Stentiford et al. 2009].

2.2.1. YHD in Scylla Species 2.2.1.1. YHD in Scylla Serrata Although mud crabs were not listed as being susceptible to YHV infection by the Directive 2006/88/EC, studies by Longyant et al. [2006] discovered mud crabs to be susceptible to the YHV infection and YHD development. S. serrata being experimentally injected with YHV showed 71.43% cumulative mortality in 3 days post-injection, and 85.71% cumulative mortality at 6 days post-injection [Longyant et al. 2006]. This finding inferred the high virulence of YHV in mortality causation. For other mud crab species, no experiments on YHV susceptibility had been reported. In fact, there had been no report on YHV susceptibility tests on any other crab species as well.

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2.3. Taura Syndrome The Taura syndrome (TS) was first discovered in ill and moribund white shrimps Penaeus vannamei that inhabited Taura River in Ecuador in 1992. The disease and its cause, TSV, were named following the discovery place [Stentiford et al. 2009]. The disease was initially found in the Americas, and was introduced to Asian countries through import of infected shrimps and shrimp products from Central and South America [Tu et al. 1999, Nielson et al. 2005]. TSV is a small, non-enveloped, positive-sense ssRNA virus in the family Dicistroiridae. TSV has icosahedral shape with average diameter size of 32 nm [Fauquet et al. 2005]. Capsid is constituted of three major (55, 44 and 24 kiloDaltons) and one minor (58 kiloDaltons) polypeptide proteins. Strain variation sometimes affects accurate diagnosis. The reason was because genetic variation of virion protein 1 (VP1) and other viral coat proteins affect viral reactivity to monoclonal antibody. Presently, more than three TSV variants, such as the American group, the South-East Asian group and the Belize group, have been identified. Moreover, each group could be further subdivided into more than one type based on host tissue tropism and virulence [Poulos et al. 1999, Chang et al. 2004, Nielsen et al. 2005, Tang and Lightner 2005, Stentiford et al. 2009]. The disease could be categorized into two

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phases: acute and chronic phases [Lightner 1996, Hasson et al. 1999]. The acute phase is represented by an expansion of red-colored lesions, soft shell and empty gut, with the cumulative mortality of up to 80-95% in penaeid shrimps. The chronic phase represents the recovery or survival phase of the diseased animals that sometimes exhibit several color lesions albeit the animal health returned to normal. These animals carried active TSV and could transmit TSV [Stentiford et al. 2009]. TSV is relatively resistant in seawater, so the horizontal transmission of TSV through water routes had been documented [White et al. 2002]. Aquatic insects and sea birds could serve as mechanical vectors for horizontal TSV transmission. The vertical transmission was also suspected, because TS was often diagnosed among nursery phase shrimps at 40 days of age [Stentiford et al. 2009]. Currently, only shrimps P. setiferus, P. stylirostris and P. vannamei and not crabs were listed in the Directive 2006/88/EC as susceptible to TSV. Recent data suggested many other shrimp species as susceptible to TSV, for instances, P. duorarum, P. chinensis, P. aztecus and Metapenaeus ensis [Stentiford et al. 2009].

3. VARIATIONS AMONG RESEARCH PROTOCOLS Researches by different laboratories were sometimes conducted differently. Review on researches on the morbidity and mortality of crabs to various viral pathogens pointed out many inconsistencies among the research protocols and techniques. Examples of variations included methods of crab species identification, genders and ages of specimens, inoculation amount per crab, methods of inoculation, types of samples used for virus quantification (i.e. hemocytes vs. tissues of specific organs), and methods of virus quantification. The consistency and accuracy in speciation of Scylla is very vital. The standard method for species identification of the mud crabs remained varied among laboratories, and different methods could affect the species identification of Scylla [Imai et al. 2004]. For instance, the species classification based on external morphology and gametogenesis was sometimes inconsistent, because external morphology and gametogenesis could fluctuate according to surrounding conditions [Overton et al. 1997; Gopurenko and Hughes 2002]. Scientists attempted to categorize Scylla species using randomly amplified polymorphic DNA (RAPD) and allozyme

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electrophoresis [Keenan et al. 1998; Klinbunga et al. 2000]. The prior technique required multiple RAPD markers and could not distinguish between S. olivacea and S. paramamosain, the two main Scylla spp. in many regions. The latter technique had problems with different results despite the same gel buffer system [Imai et al. 2004]. Recently, Imai et al. [2004] developed a more reliable method to identify S. olivacea, S. paramamosain, S. serrata and S. tranquebarica, using PCR targeting the mitochondrial 16S ribosomal RNA gene together with restriction fragment length polymorphism (RFLP). Nonetheless, the patterns of electrophoretic PCR and restriction fragments were ambiguous for S. serrata and S. paramamosain, a variant of S. serrata. Hence, Somboonna et al [2010] performed sequencing of the amplified mitochondrial 16S rDNA PCR, and identified species of Scylla by sequence alignment and BLASTN (http://www.ncbi.nlm.nih.gov/blast/ Blast.cgi?PAGE =Nucleotides). Gender and age of the crabs are another factor. Typically, male adult crabs are used for the experiments because of no fluctuation in hormone pattern [Ye et al. 2009]. Conversely, females have ovary-producing periods. In mud crabs, folliclestimulating hormone (FSH)-like and luteinizing hormone (LH)-like proteins were detected and functioned to stimulate gametogenesis. For instance, FSHlike protein is low during early developmental stage, and is highest during maturation stage to accelerate ovarian development and yolk accumulation. The instability of the hormones throughout different developmental life stages of the mud crabs could affect the health status and susceptibility of the crabs to the infection and disease development [Ye et al. 2006]. Inoculation amount and method of inoculation are factors directly associated with the results. As the weight of each crab varied, the bigger-size crab must be inoculated with more copy number of viruses to reach the same final concentration of viral copy number per gram of weight. Hence, many researches weighed each individual crab and calculated inoculation amount per gram of crab weight [Liu et al. 2011, Longyant et al. 2006, Somboonna et al. 2010]. Experimental infection by intramuscular injection was more effective than natural infection by oral feeding and bathing. Seven-day oral feeding is still less effective than one time injection [Supamattaya et al. 1998, Rajendran et al. 1999, Hameed et al. 2003]. The virus inoculation by injection method was generally considered the most effective route [Supamattaya et al. 1998, Rajendran et al. 1999, Hameed et al. 2003].

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Types of samples, such as hemocytes and tissues of specific organs, might also have an effect on the quantity of the detecting viruses. Some viruses may have different tissue tropisms, and thus may not be detected abundantly in certain organs, while the others are. Choices of virus detection and quantification methods are another factor to be considered. Generally, in-house PCR along with semi-quantitation using agarose gel electrophoresis may be less reliable than commercial, semiquantitative PCR and real-time PCR. Examples of commercial WSSV and YHV detection and quantification kits are IQ2000™ WSSV Detection and Prevention System and IQ2000™ YHV Detection and Prevention System by Farming IntelliGene Technology Corporation (Taipei, Taiwan). Both kits provide controls and standards for quantification of the copy number of viruses. In addition, confirmation of the DNA or RNA results via histology, immunofluorescence and electron microscopy techniques are important to validate the actual presence of the viruses [Poulos et al. 1999, Chang et al. 2004, Nielsen et al. 2005, Tang and Lightner 2005, Stentiford et al. 2009]. Furthermore, the appropriate controls of each step of the experiment are imperative. For in vivo test in crabs, the control group comprising of crabs of the same species, weight, gender, and injection practice except with the sterile buffer instead of the virus inoculum should be studied in parallel. For viral detection and quantification, additional controls, such as no template control and virus standard (positive) control, should be included. Further, if histology and immunofluorescence were performed to confirm the presence of the viruses, then additional controls, such as no infected cells and cells infected with different virus types to check for the specificity of the stain, were required [Somboonna et al. 2010].

4. POTENTIAL THREATS TO OTHER ANIMAL SPECIES AND THE ECOSYSTEM Movement and relocation of the symptomatic and asymptomatic crabs also affect the widespread transmission of the disease. Viral-infected crabs, either symptomatic or asymptomatic, and either alive or in frozen products, pose threats to the health of the consumers and other animals whose developmental life cycles have associated networks with them. The association can be direct or indirect. Direct associations are through eating of infected crab

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tissues by other aquatic species, feeding of infected crab tissues and extracts to farming crustaceans, and through cell-free virus suspensions in water, for examples. Eating and feeding of the infected tissues and the infected extracts are common methods of disease transmission in nature and culture environments [Flegel 2006, Flegel 2007, Sarathi et al. 2008, Escobedo-Bonilla et al. 2008, Stentiford et al. 2009, Liu et al. 2011]. Trading of crustaceans infected with WSSV, YHV and TSV had been documented in Asian, US and European markets. Indirect associations are often through asymptomatic carriers, such as sea birds and insects [Escobedo-Bonilla et al. 2008, Stentiford et al. 2009]. Additionally, virus contamination on fertilized eggs through contaminated water was reported [Stentiford et al. 2009]. Mud crabs are considered a dangerous threat for aquatic disease transmission, because they have a relatively high resistance to many viral diseases compared with other crab types. Yet, the pathogens like WSSV and YHV could still infect and use the mud crabs as carriers, reservoirs or amplifiers. As the mud crabs may appear healthy, the infecting and replicating viruses were not noticed by the farmers and the import-export screening unless being examined by nucleic acid, protein or serological detection methods [Kanchanaphun et al. 1998, Supamattaya et al. 1998, Rajendran et al. 1999, Somboonna et al. 2010]. Besides, mud crabs represent one main element of the aquatic ecosystems. Crabs are omnivores, and have interactions with many species. Moreover, studies have demonstrated the more signified threat when the viruses could establish new infection and replicative niche [Stentiford et al. 2009]. The new hosts may allow the viruses to come up with a new virulence mechanism that is novel and more effective. Because crustaceans likely have no immune responses against the newly adapted viruses, outbreaks can likely occur. At present, neither therapeutic products nor preventative strategies is yet available to effectively control the WSSV, YHV and TSV infections [Escobedo-Bonilla et al. 2008]. This emphasizes the importance of WSD, YHD and TS awareness and prompt management. Viruses pose potential threats to diverse crustaceans, with or without disease, nature or cultivated environments, as well as the ecosystem. Trading of diseased crustaceans costs no or substantially reduces financial value and credit [Stentiford et al. 2009].

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5. ADVANTAGES OF BETTER UNDERSTANDING OF THE WSD SUBSCEPTIBILITY AMONG CRAB SPECIES Understanding the degree of susceptibility of each mud crab species to WSD helps aquaculture improvement, and planning for inspection guidelines and risk management for local and international trading of live and frozen crab meats and meat extracts. The species of crabs with the greater susceptibility level to the disease development should be inspected with advanced care. Meanwhile, the asymptomatic species should also be examined [Somboonna et al. 2010]. As co-cultivation between mud crabs and penaeid shrimps are common, the knowledge on disease susceptibility and disease transmission from healthily-appeared crabs helps the culture plan management. Another benefit of the knowledge is a general guideline for the crab farmers and crab industries on a better choice of crab species for cultivation. For examples, cultivation of S. olivacea might be better than S. paramamosain and S. serrata, in orderly [Rajendran et al. 1999, Somboonna et al. 2010, Liu et al. 2011]. As WSD in Scylla was found to be species-, dose- and historydependent, cultivation of the greater disease-resistant species of mud crabs may likely result in less cultivation loss due to disease outbreak. Following literature review, S. olivacea is more resistant to the WSD than S. paramamosain, and S. paramamosain is more resistant to the WSD than S. serrata [Kanchanaphum et al. 1998, Supamattaya et al. 1998, Rajendran et al. 1999, Somboonna et al. 2010, Liu et al. 2011]. In addition, pre-challenging with low dose viruses seemed to boost the crab immunity against the viruses. Somboonna et al. [2009] compared the effects of single-injection and serialdose injection, and found that pre-challenging of S. paramamosain and S. olivacea with low viral doses prior to the high dose challenge resulted in the fewer number of moribund crabs than the one-time challenge at the high dose. This finding was consistent with the field reports that more number of aquatic survivals were found after an outbreak in the regions where outbreaks of the same viral types used to be found [Flegel 2007].

CONCLUSION Different species of mud crabs have different tolerances to morbidity and mortality caused by the viruses in a dose- and history-dependent manner. For WSSV, S. olivacea is more disease-resistant than S. paramamosain and S.

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serrata, respectively. Following experimental data and epidemiology analyses, the immunity of the crabs was heightened by pre-exposure to low-dose WSSV challenges, either by experimental or natural routes [Flegel 2007, Somboonna et al. 2010]. Moreover, as asymptomatic mud crabs showed the ability of disease transmission, trading of animals that exhibit no visual sign of disease for diet, broodstock enhancement and others might still require random inspections. All forementioned activities could potentially allow exposure of the contaminated viruses to the community and the ecosystem [Supamattaya et al. 1998 Flegel 2006, Kanchanaphum et al. 1998,].

ACKNOWLEDGMENTS

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The author thanked Mr. Kanapat Benjawongsathien and Assistant Professor Dr. Doonyapong Wongsawaeng for assistance in the chapter preparation. This chapter was supported in part by Ratchadaphiseksomphot Endowment Fund, Chulalongkorn University, for new faculty members (to N. Somboonna).

REFERENCES Boonyaratpalin, S; Supamataya, K; Kasornchandra, J; Direkbusarakorn, S; Ekpanithanpon, U; Chantanachookin, C. Non-occluded baculo-like virus the causative agent of yellow-head disease in the black tiger shrimp Penaeus monodon. Fish Pathol., 1993; 28:103-9. Chang, YS; Peng, SE; Yu, HT; Liu, FL; Wang, CH; Lo, CF; Kou, GH. Genetic and phenotypic variations of isolates of shrimp Taura syndrome virus found in Penaeus monodon and Metapenaeus ensis in Taiwan. J. Gen. Virol., 2004; 85:2963-8. Chantanachookin, C; Boonyaratpalin, S; Kasornchandra, J; Direkbusarakorn, S; Aekpanithanpong, U; Sypamattaya, K; Sriuraitana, S; Flegel, TW. Histology and ultrastructure reveal a new granulosis-like virus in Penaeus monodon affected by yellow-head disease. Dis. Aquat. Organ., 1993; 17:145-57. Chen, LL; Lo, CF; Chiu, YL; Chang, CF; Kou, GH. Natural and experimental infection of white spot syndrome virus (WSSV) in benthic larvae of mud crab Scylla serrata. Dis. Aquat. Organ., 2000; 40:157-61.

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Cholik, F; Hanafi, A. 1991. A. review of the status of mud crab (Scylla sp.) fishery culture in Indonesia. In: Angell, C.A. (ed.), Report of the Seminar on the Mud Crab Culture and Trade, held at Surat Thani, Thailand, November 5–8, 1991. Bay of Bengal Program, BOBP/ REP/51, Madras, India. Christensen, SM; Macintosh, DJ; Phuong, NT. Pond production of the mud crabs Scylla paramamosain (Estampador) and S. olivacea (Herbst) in the Mekong Delta, Vietnam, using two different supplementary diets. Aquaculture Res., 2004; 35:1013-24. Cowley, JA; Dimmock, CM; Spann, KM; Walker, PJ. Gill-associated virus of Penaeus monodon prawns: an invertebrate virus with ORF1a and ORF1b genes related to arteri- and coronaviruses. J. Gen. Virol., 2000; 81:147384. Cowley, JA; Walker, PJ. The complete genome sequence of gill associated virus of Penaeus monodon prawns indicates a gene organization unique among nidoviruses. Arch. Virol., 2002; 147:1977-87. Davie, PJF. 1998. Wild guide to Moreton Bay. Wildlife and habitats of a beautiful Australian coast — Noosa to the Tweed. Brisbane, Queensland Museum. pp 408. scobedo-Bonilla, CM; Alday-Sanz, V; Wille, M; Sorgeloos, P; Pensaert, MB; Nauwynck, HJ. A review on the morphology, molecular characterization, morphogenesis and pathogenesis of white spot syndrome virus. J. Fish. Dis., 2008; 31:1-18. Fauquet, CM; Mayo, MA; Maniloff, J; Desselberger, U; Ball, LA. 2005. Virus taxonomy: classification and nomenclature of viruses. Eighth Report of the International Committee on Taxonomy of Viruses. Elsevier, Academic Press, pp. 1-1259. Flegel, TW. Special topic review: major viral diseases of the black tiger prawn (Penaeus monodon) in Thailand. World J. Microb. Biol., 1997; 13:433-42. Flegel, TW. Detection of major penaeid shrimp viruses in Asia, a historical perspective with emphasis on Thailand. Aquaculture, 2006; 258:1-33. Flegel, TW. Update on viral accommodation, a model for host-viral interaction in shrimp and other arthropods. Dev .Comp. Immunol., 2007; 31:217-31. Fortes, RD. Mud crab research and development in the Philippines: an overview. ACIAR Tech. Rep., 1999; 78:27-32. Fushimi, H; Watanabe, S. Problems in species identification of the mud crab genus Scylla (Brachyura: Portunidae). UJNR Tech. Rep., 1999; 28:9-14. Gopurenko, D; Hughes, JM. Regional patterns of genetic structure among Australian populations of the mud crab Scylla serrata (Crustacea:

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Decapoda): evidence from mitochondrial DNA. Mar. Freshw. Res., 2002; 53:849-857. Hasson, KW; Lightner, DV; Mohney, LL; Redman, RM; Poulos, BT; White, BM. Taura syndrome virus (TSV) lesion development and the disease cycle in the Pacific white shrimp Penaeus vannamei. Dis. Aquat. Organ., 1999; 36:81-93. Hossain, S; Chakraborty, A; Joseph, B; Otta, SK; Karunasagar, I; Karunasagar, I. Detection of new hosts for white spot syndrome virus of shrimp using nested polymerase chain reaction. Aquaculture, 2001; 198:111. Imai, H; Cheng, J-H; Hamasaki, K; Numachi, K-I. Identification of four mud crab species (genus Scylla) using ITS-1 and 16S rDNA markers. Aquat. Living Resour, 2004; 17:31-4. Jitrapakdee, S; Unajak, S; Sittidilokratna, N; Hodgson, RAJ; Cowley, JA; Walker, PJ; Panyim, S; Boonsaeng, V. Identification and analysis of gp116 and gp64 structural glycoproteins of yellow head nidovirus of Penaeus monodon shrimp. J. Gen. Virol., 2003; 84:863-73. Kanchanaphum, P; Wongteerasupaya, C; Sitidilokratana, N; Boonsaeng, V; Panyim, S; Tassanakajon, A; Withyachumnarnkul, B; Flegel, TW. Experimental transmission of white spot syndrome virus (WSSV) from crabs to shrimp Penaeus monodon. Dis. Aquat. Organ., 1998; 34:1-7. Keenan, CP; Davie, PJF; Mann, DL. A revision of the genus Scylla De Haan, 1883 (Crustacea: Decapoda: Brachyura: Portunidae). Raffles Bull. Zool., 1998; 46:217-45. Keenan, CP. The fourth species of Scylla. ACIAR Tech Rep 1999; 78: 48-58. Sugama, K; Hutapea, JH. Genetic characterization in the mud crab Scylla (Brachyura: Portunidae). ACIAR Tech. Rep., 1999; 78:43-7. Klinbunga, S; Boonyapakdee, A; Pratoomchat, B. Genetic diversity and species-diagnostic markers of mud crabs (Genus Scylla) in Eastern Thailand determined by RAPD analysis. Mar. Biotechnol., 2000; 2:180187. Lightner, DV (Ed.). 1996. A handbook of shrimp pathology and diagnostic procedures for diseases of cultured penaeid shrimp. World Aquaculture Society, Baton Rouge, Louisiana, USA. pp. 1-304. Liu W; Qian D; Yan XJ. Studies on pathogenicity and prevalence of white spot syndrome virus in mud crab, Scylla serrata (Forskal), in Zhejiang Province, China. J. Fish. Dis., 2011; 34:131-8. Lo, CF; Ho, CH; Chen, CH; Liu, KF; Chiu, YL; Yeh, PY; Peng, SE; Hsu, HC; Liu, HC; Chang, CF; Su, MS; Wang, CH; Kou, GH. Detection and tissue

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tropism of white spot syndrome reproductive organs. Dis. Aquat. Organ., 1997; 30:53-72. Lo, CF; Kou, GH. Virus-associated white spot syndrome of shrimp in Taiwan: a review. Fish, Longyant, S; Sithigorngul, P; Chaivisuthangkura, P; Rukpratanporn, S; Sithigorngul, W; Menasveta, P. Differences in susceptibility of palaemonid shrimp species to yellow head virus (YHV) infection. Dis. Aquat. Organan., 2005; 64:5-12. Lu, Y; Tapay, LM; Brock, JA; Loh, PC. Infection of the yellow head baculolike virus (YBV) in two species of penaeid shrimp Penaeus stylirostris (Stimpson) and Penaeus vannamei (Boone). J. Fish. Dis., 1994; 17:64956. Marks, H; Goldbach, RW; Vlak, JM; van Hulten, MCW. Genetic variation among isolates of white spot syndrome virus. Arch. Virol., 2004; 149:67397. Mayo MA. Virus taxonomy – Houston 2002. Arch. Virol., 2002; 147:1071-6. Moser, S; Macintosh, D; Laoprasert, S; Tongdee, N. Population ecology of the mud crab Scylla olivacea: a study in the Ranong mangrove ecosystem, Thailand, with emphasis on juvenile recruitment and mortality. Fishery Res., 2005; 71:27-41. Nielsen, L; Sang-Oum, W; Cheevadhanarak, S; Flegel, TW. Taura syndrome virus (TSV) in Thailand and its relationship to TSV in China and the Americas. Dis. Aquat. Organ., 2005; 63:101-6. Overton, JL; Macintosh, DJ; Thorpe, RS. Multivariate analysis of the mud crab Scylla serrata (Brachyura: Portunidae) from four locations in Southeast Asia. Mar. Biol., 1997; 128:55-62. Poulos, BT; Kibler, R; Bradley-Dunlop, D; Mohney, LL; Lightner, DV. Production and use of antibodies for the detection of the Taura syndrome virus in penaeid shrimp. Dis. Aquat. Organ., 1999; 37:99-106. Rajendran, KV; Vijayan, KK; Santiago, TC; Krol RM. Experimental host range and histopathology of white spot syndrome virus (WSSV) infection in shrimp, prawns, crabs and lobsters from India. J. Fish. Dis., 1999; 22:183-91. Rodríguez, J; Bayot, B; Amino, Y; Panchana, F; De Blas, I; Alday, V; Calderon, J. White spot syndrome virus infection in cultured Penaeus monodon (Boone) in Ecuador with emphasis on histopathology and ultrastructure. J. Fish Dis., 2003; 26:439-50. Sahul-Hameed, AS; Charles, MX; Anilkumar, M. Tolerance of Macrobrachium rosenbergii to white spot syndrome virus. Aquaculture, 2000; 183:207-13.

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Sarathi, M; Basha, AN; Ravi, M; Venkatesan, C; Kumar, BS; Hameed, ASS. Clearance of white spot syndrome virus (WSSV) and immunological changes in experimentally WSSV-injected Macrobrachium rosenbergii. Fish and Shellfish Immunol., 2008; 25:222-30. Sittidilokratna, N; Hodgson, RAJ; Cowley, JA; Jitrapakdee, S; Boonsaeng, V; Panyim, S; Walker, PJ. Complete ORF1b-gene sequence indicates yellow head virus is an invertebrate nidovirus. Dis. Aquat. Organ., 2002; 50:8793. Somboonna, N; Mangkalanan, S; Udompetcharaporn, A; Krittanai, C; Sritunyalucksana, K; Flegel, TW. Mud crab susceptibility to disease from white spot syndrome virus is species-dependent. BMC Res Notes 2010; 3:315 (http://www.biomedcentral.com/1756-0500/3/315). Soowannayan, C; Flegel, TW; Sithigorngul, P; Slater, J; Hyatt, A; Cramerri, S; Wise, T; Crane, MSJ; Cowley, JA; McCulloch, RJ; Walker, PJ. Detection and differentiation of yellow head complex viruses using monoclonal antibodies. Dis. Aquat. Organ., 2003; 57:193-200. Stentiford, GD; Bonami, J-R; Alday-Sanz, V. A critical review of susceptibility of crustaceans to Taura syndrome, Yellowhead disease and White Spot Disease and implications of inclusion of these diseases in European legislation. Aquaculture, 2009; 291:1-17. Supamattaya, K; Hoffmann, RW; Boonyaratpalin, S; Kanchanaphun, P. Experimental transmission of white spot syndrome virus (WSSV) from black tiger shrimp Penaeus monodon to the sand crab Portunus pelagicus, mud crab Scylla serrata and krill Acetes sp. Dis. Aquat. Organ., 1998; 32:79-85. Tang, KFJ; Lightner, DV. Phylogenetic analysis of Taura syndrome virus isolates collected between 1993 and 2004 and virulence comparison between two isolates representing different genetic variants. Virus. Res., 2005; 112:69-76. Tu, C; Huang, HT; Chuang, SH; Hsu, JP; Kuo, ST; Li, NJ; Hus, TL; Li, MC; Lin, SY. Taura syndrome in Pacific white shrimp Penaeus vannamei cultured in Taiwan. Dis. Aquat. Organ., 1999; 38:159-61. Turkay, M; Sakai, K. Decapod crustaceans from a volcanic hot spring in the Marianas. Senckenbergiana Maritime, 1995; 26: 25-35. Walker, PJ; Cowley, JA; Spann, KM; Hodgson, RAJ; Hall, MR; Withyachumnarnkul, B. 2001. Yellow head com plex viruses: transmission cycles and topographical distribution in the Asia-Pacific Region. In Browdy, CL and Jory, DE (Eds.), The New Wave, Proceeding

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of the Special Session on Sustainable Shrimp Culture, Aquaculture 2001. The World Aquaculture Society, Baton Rouge, LA, USA, pp. 292-302. Wang, YG; Hassan, MD; Shariff, M; Zamri, SM; Chen, X. Histopathology and cytopathology of white spot syndrome virus (WSSV) in cultured Penaeus monodon from peninsular Malaysia with emphasis on pathogenesis and the mechanism of white spot formation. Dis. Aquat. Organ., 1999; 39:1-11. Wang, Q; Poulos, BT; Lightner, DV. Protein analysis of geographic isolates of shrimp white spot syndrome virus. Arch. Virol., 2000; 145:263-74. Webley, JAC; Connolly, RM. Vertical movement of mud crab megalopae (Scylla serrata) in response to light: doing it differently down under. J. Exp. Mar. Biol. and Ecol., 2007; 341:196-203. White, BL; Schofield, PJ; Poulos, BT; Lightner, DV. A laboratory challenge method for estimating Taura syndrome virus resistance in selected lines of Pacific white shrimp Penaeus vannamei. J. World Aquac. Soc., 2002; 33:341-8. Wijegoonawardane, P; Cowley, JA; Kiatpathomchai, W; Meilsen, L; Walker, PJ. 2004. Phylogenetic analysis and evidence of genetic recombination among six genotypes of yellow head complex viruses from Penaeus monodon. Book of Abstracts. 7th Asian Fisheries Forum, Penang, Malaysia, 2004, pp. 1-210. Wongteerasupaya, C; Sriurairatana, S; Vickers, JE; Akrajamorn, A; Boonsaeng, V; Panyim, S; Tassanakajon, A; Withyachumnarnkul, B; Flegel, TW. Yellow-head virus of Penaeus monodon is an RNA virus. Dis. Aquat. Organ., 1995a; 22:45-50. Wongteerasupaya, C; Vickers, JE; Sriurairatana, S; Nash, GL; Akarajamorn, A; Boonsaeng, V; Panyim, S; Tassanakajon, A; Withyachumnarnkul, B; Flegel, TW. A non-occluded, systemic baculovirus that occurs in cells of ectodermal and mesodermal origin and causes high mortality in the black tiger prawn Penaeus monodon. Dis. Aquat. Organ., 1995b; 21:69-77. Ye, HH; Huang, HY; Li, SJ; Wang, GZ. Immuno-recognition of FSH and LH in the cerebral ganglia of the mud crab, Scylla paramamosain. Progress in Nat. Sci., 2006; 16:768-70 (in Chinese). Ye, HH; Huang, HY; Wang, GZ; Li, SJ. Occurrence of gonadotropins like substance in the thoracic ganglia mass of the mud crab, Scylla paramamosain (Crustacea: Decapoda: Brachyura). Acta Oceanologica Sinica, 2009; 28:76-80.

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Yoganandhan, K; Thirupathi, S; Hameed, AS. Biochemical, physiological and hematological changes in white spot syndrome virus-infected shrimp, Penaeus indicus. Aquaculture, 2003; 221:1-11.

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Copyright © 2012. Nova Science Publishers, Incorporated. All rights reserved. Crabs: Anatomy, Habitat and Ecological Significance : Anatomy, Habitat and Ecological Significance, Nova Science

In: Crabs: Anatomy, Habitat, Editors: K. Saruwatari, M. Nishimura

ISBN: 978-1-61942-225-4 © 2012 Nova Science Publishers, Inc.

Chapter 2

DEVELOPMENT OF TRAPPING GEAR AND METHODS FOR SWIMMING CRABS Miguel Vazquez Archdale*

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Field of Fisheries Engineering, Faculty of Fisheries, Kagoshima University, Kagoshima City, Japan

ABSTRACT When looking at the capture process of traps targeting aquatic organisms, there are factors which fishers can control and others which they cannot. Examples of those beyond their control are the physical parameters of the fishing ground, such as depth, water temperature or type of substrate; and the physiological condition of the target organism, such as hunger state or molting stage. Factors that can be controlled include the attractiveness of the bait used and the design of the fishing gear employed. Through history, traps have proven to be an effective tool for harvesting crustaceans. They are small, simple, cheap and can be carried in large numbers stacked onboard small boats. Traps are qualified as passive fishing gear because they are dropped on the seafloor and left unattended for hours or days. The target organisms are commonly lured towards them using bait, and it is the attractiveness of this bait that is most important and will determine the quantity and quality of the catch. Improving the luring methods and the attractiveness of bait for crabs will *

E-mail: [email protected]

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Miguel Vazquez Archdale be discussed, beginning with the determination of the most attractive substances contained in them, which consist mostly of amino acids and sugars. Based on these findings, a novel fishing method that employs a bait combination of fish and sugarcane will be introduced, which has resulted in a great increase in the crab catch. Following bait, second in importance is the design of the fishing gear. After the target animal has been lured towards and is in contact with a trap, the design and the type of entrance will determine the number of crabs that will enter and, consequently, the success of the fishing operation. In order to find the reasons why some trap designs and entrance types are more efficient at catching crabs rather than others it is insufficient to compare the catches of different gear designs during fishing trials. It is essential to make observations on the behavior of crabs around the traps, and this can be accomplished by placing both baited traps and crabs on the seafloor or inside large tanks, and recording their interactions by video. Improvements on trap design can be made after observing how crabs behave after they reach the trap and by determining the difficulties they encounter finding the entrances. Observations on crab behavior around different trap designs showed that they search larger areas around traps with oval bases than those with rectangular ones, and this gives them more access to the trap entrances. Open funnel entrances allowed entry of most crabs contacting the traps and were superior to tight slit entrances, which only permitted ingress of a smaller number because the netting material entangled with the spines of the crabs and many gave up after several attempts. Traps fitted with open entrances also tended to catch fewer non-target animals and permitted the escape of animals, which resulted in them being more environmentally friendly by reducing the non-target catch and the negative impact that lost gear causes on the aquatic resources by ghost fishing.

INTRODUCTION Crustacean trap fisheries are some of the worlds most valuable, and swimming crabs are an important fisheries resource that supports a very profitable fishery in many parts of the world. According to the FAO (2004) the annual catch of crabs in 2002 was more than one million metric tons, of which more than 370,000 were swimming crabs Portunus spp. Japan imports about 50 thousand tons of fresh crabs and the same amount of frozen ones, which amount to a value of almost $1 million. Among the many crab species present in Japanese waters, only a few are of commercially important value, and swimming crabs represent the largest commercial fisheries (Takeda 1983)

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Development of Trapping Gear and Methods for Swimming Crabs

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supporting a 6-8 billion yen per year industry with catches ranging from 4.15.6 thousand metric tons (Morioka et al. 1988). Out of all swimming crabs, the Japanese coastal waters support commercial fisheries for only several species. One of them is the blue swimming crab Portunus pelagicus, which is distributed throughout the Pacific and Indian Oceans, and extends all the way to the Mediterranean Sea through the Suez Canal (Takeda 1983, Williams 1982). It inhabits intertidal areas like sand flats, river mouths and mangrove swamps and is seldom found in offshore waters (Stephenson and Campell 1959). This crab is fished throughout the year, particularly during summer and fall, and is caught with haul nets, gill nets and crab traps (Takeda 1983, Thomson 1951); it reaches a high price in the market (1,100 - 2,000 yen/kg) and is highly appreciated for its taste. Another is the shore swimming crab Charybdis japonica, which inhabits the muddy, sandy and stony shores of Japan, from the coast of Choshi to Kyushu and Okinawa, extending its range to Korea, China and Taiwan (Sakai 1976). This crab is commonly caught as by-catch in traps that target more profitable species of swimming crab and octopus, and even though it does not support an important fishery it is a popular edible species. It is caught only seasonally and has a small portion of meat that is well known for its good taste (Kono et al. 1999).

Figure 1. Blue swimming crab Portunus pelagicus (left) and shore swimming crab Charybdis japonica (right).

Regarding the methods employed for harvesting swimming crabs, traps are commonly used and have many advantages over other fishing gear. Their main advantages are that the catch is easily removed, not damaged and remains alive until harvest, thus reaching a high market price. Traps also have the advantage that non-target sizes, sexes or species generally have high survival rates when returned to the sea. The number of traps handled by fishers has increased dramatically due to the motorization of the fishing vessel, the introduction of the longline method and the hydraulic trap hauler, all of which allowed for the expansion of the fishing operation (Krouse 1989). This

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required the development of trap designs with higher portability that could be stacked in large numbers on the decks of small fishing boats. The Japanese collapsible trap was made for this purpose; it occupies a minimum space and is easily unfolded just before being tossed into the sea. Collapsible traps are now the standard for harvesting swimming crabs in Japan (Anon. 1986). For this reason the study of the behavior of swimming crabs around collapsible traps is important. Knowing the factors that affect the capture process of a trap relative to its target species can be used to modify, improve and in some cases control gear efficiency and overall catch characteristics (Krouse 1989). In the first section of this chapter I will discuss the importance of the bait used to attract the target organisms towards the trap, and how through behavioral experiments the attractive quality of this bait can be improved to increase catches. Later, I will introduce how I determined the best trap design by carefully observing the interactions of crabs with several baited trap designs.

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REASONS FOR CHOOSING TRAPS AS HARVESTING GEAR Of all the fishing methods fishers employ, traps have a long history of tested effectiveness as harvesting gear for aquatic organisms, and there are extensive examples of commercial fisheries still employing them as their preferred gear. Traps are regularly used to capture crustaceans because they are cheap, small, light and easy to operate. They take up little deck space in the fishing boat, are selective towards the catch, and will maintain a large proportion of the captured organisms alive; therefore, permitting the return of undersized and unwanted species unharmed back into the water. Traps are a passive fishing gear that is left unattended on the seafloor, and crabs have to be lured into them with the aid of bait. This relies on the locomotive power of the target animals, which have to approach the trap by themselves; therefore, this technique requires less energy and fuel than active fishing methods used to catch crustaceans, such as trawling. Furthermore, traps have lower operational costs and can be hauled manually or with smaller line haulers than other fishing gear. The Japanese collapsible crab traps are very effective fishing gear. Collapsible traps occupy less space on deck because they are two-dimensional and can be laid flat until they are assembled, just before being tossed into the sea (Figure 2). For this reason larger numbers can be carried onboard rather than those of conventional rigid trap design.

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Development of Trapping Gear and Methods for Swimming Crabs

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Figure 2. Side views of box trap with slit entrances (top) and dome trap with open funnels (bottom).

Figure 3. Fishing gear components: buoy, anchor line, chain anchor, bottom longline and collapsed traps.

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TRAP OPERATION Traps are usually baited with mackerel or sardine when the fishing boat is in the port just before going out to sea. Fishers rely on bait and the acute chemoreceptive sense of crustaceans to lure them towards the traps. The rigging used during crab fishing usually consists of individual traps fastened to a branch line, which connects them to a bottom longline. Traps are spaced at regular intervals (usually 15 m is the preferred interval for swimming crab traps), to prevent tangling and to eliminate competition between baits. The bottom longline is tied at both extremes to an anchor or weight, and to another line connected to a marker buoy, which serves to locate and haul the traps back onto the boat (Figure 3).

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THE CAPTURE PROCESS The traps used to catch crustaceans are usually set on the sea before sunset and hauled after dawn, so that the time they spend in the fishing ground coincides with the active phase of the target species. Swimming crabs are mostly nocturnal, though they also show short periods of activity during the day, and as a result have to rely mostly on their chemoreceptive sense to find food or prey.

Figure 4. Illustration showing the capture process of a crab approaching a baited trap.

The capture process of an aquatic animal approaching a trap has been summarized as consisting of several behavioral stages (Furevik 1994), which start with distant detection, and continue with approach, contact, near ingress

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behavior, entry, and end with capture and/or escape (Figure 4). The first two, detection and approach are mediated by the chemoreceptive sense of the organism and are influenced by the distribution of the odor emanating from the baited trap as the current carries it downstream.

LURING THE CRAB TO THE TRAP

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Bait Many fishers use fish of no commercial value or “trash fish” as bait, but animal by-products such as viscera, skin or heads, salted or dried fish, smoked cormorant, frogs, chicken offal and many other things can be used as well. Commercial trap fishers usually prefer to use frozen fish bait, like mackerel or sardine, because from past experience they know that to have a good catch they need high quality bait. Some studies have examined the active ingredients found in bait that are responsible for the attraction that induces animals to move into the trap. Swimming crabs are scavengers that rely heavily on their chemoreceptive sense for locating their food. Their nose-equivalent is a small appendage resembling an antenna called the “antennule”, and the two they possess are located just between their eyes. Their entire body surface is also lined with chemical and mechanical receptors, so that walking legs, mouthparts and claws act as sensors that help them locate and handle their prey. Water-soluble compounds from damaged tissues, excretions and decaying organisms act as strong stimuli and affect crab feeding behavior, and this explains why fishers employ bait to attract crabs into traps. Research conducted to identify individual attracting substances found in decapod crustacean food and prey has been carried out in the past, mostly by bioassay and electrophysiological experiments. Isolating stimulating compounds from natural prey organisms and testing them with live decapods, or appendage preparations where the receptors are still viable, have elucidated that substances of low molecular weight, such as amino acids, saccharides (sugars), nucleotides and ammonium compounds, are mostly responsible for the food searching responses elicited by the bait (Ache 1982, Carr 1988). Other findings have documented that different species of decapods respond to different mixtures of these compounds, and that the effect of mixing individual substances is synergistic. By studying the behavior of swimming crabs placed in aquaria after adding a known volume of fish extract to the seawater in which they are held,

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a characteristic food searching sequence can be observed. Swimming crabs kept in aquaria tend to remain burrowed in the sand substrate until stimulated by some of the soluble substances emanating from a food item. Once exposed to fish extract they increased the rate of antennule flicking (equivalent to sniffing through our nose), moved their mouthparts, and crawled searching for food around the aquarium while prodding its sandy bottom with legs and claws trying to find the food item. Once this behavioral sequence is observed, identifying stimulating substances can be easily accomplished by adding individual chemicals diluted in seawater at increasing concentrations with a dropper and observing which of them elicit the crabs to rise out of the sand and search for food (Figure 5 bottom right). Following this method, individual stimulating substances can be determined, together with their sensitivity thresholds.

Figure 5. Tank set-up for chemostimulation experiments (left), P. pelagicus buried in the sand (left and top right) and searching for food (bottom right).

Bioassay experiments using the blue swimming crab P. pelagicus have shown that the most stimulatory amino acids were alanine, arginine, betaine, glycine and serine within the 2 x 10-7 - 2 x 10-4 mol/l range; while the saccharides galactose and glucose were more stimulant than these amino acids at the same concentrations (Archdale and Nakamura, 1992, Table 1). These levels are only slightly above the low ambient amino acid levels found in seawater, which are in the range of 10-8 mol/l (Carr 1988), and they confirm

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that crabs can detect minor changes in the chemical composition of the water surrounding them. These same amino acids have been identified by chemical analysis in the prey organisms of swimming crabs, which consist mainly of other crustaceans, mollusks and polychaete worms. Saccharides are present in both the blood of fish and hemolymph of crustaceans. Though similar responses showing the dual importance of sugars in crab chemoreception have been observed in the porcelain, ghost and fiddler crabs, possible applications of using sweet bait were not investigated until 1995 (Kawamura et al. 1995), when sugarcane was tried as an alternative bait for crab traps during fishing trials.

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Table 1. Cumulative food searching responses of P. pelagicus to increasing concentrations of various solutions of individual amino acids and saccharides

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Sugarcane and Fish Bait Combinations

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After determining which substances are responsible for the stimulating nature of bait, the possibility of making it more attractive should be considered. In the previous section, sugars where found to be highly attracting to swimming crabs. Sugarcane is a cheap and readily available agricultural crop, which can be easily grown in tropical climates. The possibility of using short sections of split sugarcane as alternative bait for crab traps was tested during fishing trials in Kagoshima, southern Japan (Kawamura et al. 1995). The baiting treatments applied to the traps were sugarcane, fish bait and a combination of the two (Figure 6 top). The catches of the blue swimming crab P. pelagicus were almost doubled and those of the shore swimming crab C. japonica more than tripled in traps baited with the fish-sugarcane combination, while sugarcane alone was not very effective (Table 2). The increase in attractiveness of the bait combination was probably due to a synergistic effect resulting from the mixture of attractive sugars and amino acids present in both fish and sugarcane. Further trials carried out in Panay Island, the Philippines, using the same treatments for trap bait also confirmed the effectiveness of the bait combination, which caught 48% more crabs than those baited with fish alone (Figure 6 bottom) (Anraku et al. 2001).

Figure 6. Baiting treatments: sugarcane, fish and combination (top 3) and fishing operation using bamboo basket traps in Panay Island, the Philippines (bottom). Crabs: Anatomy, Habitat and Ecological Significance : Anatomy, Habitat and Ecological Significance, Nova Science

Development of Trapping Gear and Methods for Swimming Crabs

37

During the study in the Philippines, sugarcane baited traps still caught onethird the number of crabs caught by fish baited traps (Table 2), which is efficient enough to justify its application, as reported by some of the fishers that follow this practice locally. Sweet substances can enhance the effectiveness of ordinary fish baits for traps targeting swimming crabs, and might be used in a purer form to enrich existing fish bait and boost effectiveness. The next section will examine the possibility of enriching current fish bait with sugar. Table 2. Crab catches obtained using sugarcane, fish and their combination as bait

Target species Blue swimming crab Shore swimming crab Swimming crabs Copyright © 2012. Nova Science Publishers, Incorporated. All rights reserved.

a

Bait treatments Sugarcane Fish Combination 3

44

71

2

11

36

9

27

40

Fishing ground Kagoshima, Japana Nagashima, Japana Panay, Philippinesb

Kawamura et al. 1995; b Anraku et al. 2001

Fish Mince in Teabag Bait Enriching the bait with attractants, in the same way aquaculture feeds are supplemented with vitamins and minerals, has become a new possibility. Teabags have been used to bind fish processed into mince and may be used as a cheaper alternative to conventional fish bait (Vazquez Archdale et al. 2008). The fish can be minced using a meat chopper and packed into large teabags and used as alternative bait. Traps baited with fish mince teabags caught approximately as many crabs as those using the same amount of ordinary unprocessed fish (Table 3). The commercial crab species captured were the blue swimming crab P. pelagicus and shore swimming crab C. japonica, while the four-lobed swimming crab Thalamita sima and red swimming crab Thalamita prymna are not commonly exploited. The remains of the fish bait found in the traps indicated that crabs prefer to consume the viscera of the fish employed; therefore, the possibility of making cheaper bait using only fish byproducts, such as head, internal organs, skin and bones, should be tested in the

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Miguel Vazquez Archdale

future. This would save a considerable amount of edible fish that can be destined for human food or animal feed.

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Table 3. Number of trapped organisms according to bait type (100 traps/treatment) Catch organisms Crab catch Four-lobed swimming crab Red swimming crab Shore swimming crab Blue swimming crab Total crab catch

Fish 721 34 28 67 850

Baiting treatment Mince in teabag No bait 601 40 41 26 2 66 734 42

Others

74

144

68

This novel binding method was also used to investigate whether adding sugar to the fish mince would increase crab catches. The results showed no significant differences to using conventional fish bait in traps for P. pelagicus (Table 4); but C. japonica and other swimming crab species disliked the sweet mince and were caught at half the rates of fish baited traps, which means that the taste preference varies depending on the crab species, and indicates that more selective crab baits may be designed in the future. Table 4. Number of trapped organisms according to bait type (100 traps/treatment) Catch organisms Crab catch Four-lobed swimming crab Red swimming crab Shore swimming crab Blue swimming crab Total crab catch

Fish 513 28 70 76 687

Baiting treatment Sugar/mince in teabag 450 15 34 81 580

Others

44

175

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No bait 47 1 3 51 60

Development of Trapping Gear and Methods for Swimming Crabs

39

TRAP DESIGN AND CRAB BEHAVIOR After talking about the detection and approach stages of the capture process in trap fisheries we will proceed to examine what happens to a crab after it contacts the trap. Several studies have documented how trap design affects capture efficiency. Crabs normally crawl along the sea bottom until they encounter an odor trail emanating from a baited trap. After sensing the bait, they will follow the trail upstream searching for the source. By zigzagging across this trail and sampling the odor concentrations of the substances in the water, crabs can easily locate and guide their way to the trap. After contacting the trap, this zigzag crawling will turn into short excursions to the right and left along the perimeter of the trap, and these will progress until the crab encounters an entrance that gives it access to the bait. It has also been observed that if they cannot find an entrance they will easily give up after a few attempts and look for food somewhere else.

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Exploration around Trap By conducting observations through an underwater video camera and recording crab behavior around collapsible traps of different shapes, it was found that the area a crab explores around the perimeter of a trap varies depending on the shape of the base (Vazquez Archdale et al. 2003).

Figure 7. Average searched angles around dome trap (left) and box trap (right) as seen from above. Crabs: Anatomy, Habitat and Ecological Significance : Anatomy, Habitat and Ecological Significance, Nova Science

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Miguel Vazquez Archdale

A trap with an oval base (Figure 7) made crabs search wider average angles (mean =173°) than a rectangular one (mean =108°), and this increased their probability of finding one of the entrances. Traps targeting swimming crabs normally have two entrances located opposite to each other; therefore, search angles approaching 180° will almost guarantee that a crab finds one of the entrances. Similar results have been observed in Korea with C. japonica, where circular traps caught more crabs on average than rectangular ones (Kim and Ko 1987).

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Behavior at Entrances In many cases the target organism can be selected by the position and design of the trap’s entrance. Collapsible traps usually have open funnel or narrow slit entrances, and these characteristics greatly affect entry rates. Underwater observations of crab behavior in different trap entrances confirmed that only 31% of the crabs contacting the slits could enter a box trap (Vazquez Archdale et al. 2003). The main reason for the low entry rate was that the spines in the crabs carapace and claws entangled with the netting material, and as a consequence they could not enter the trap nor reach the bait; many gave up and left the trap after a few unsuccessful attempts. On the other hand, 100% of the crabs that reached the open funnel entrances of the dome trap could enter by crawling sideways through the entrances, without encountering any obstruction.

Figure 8. Types and number of entries observed for crabs in box trap (left) and dome trap (right) as seen from above.

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Development of Trapping Gear and Methods for Swimming Crabs

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Complementary observations were carried out in a large indoor tank by exposing the same 30 individual crabs to both box and dome trap designs, in order to quantify their responses and entry successes (Figure 8). When placed in the tank only 63% of the crabs could enter the box trap in 1.5 hours, while 100% of the crabs entered the dome trap within the same time. Average times to entry after the crabs reached the entrance were 12.3 minutes for the box trap but only 2 minutes for the dome trap (Table 5). The average number of attempts were 13 in the box trap and only 1.3 in the dome trap, which demonstrates that crabs usually go into the latter design in only one try (Vazquez Archdale et al. 2006a).

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Table 5. Entry of Charybdis japonica into box and dome traps in tank experiment

Entrance type

Box trap (slit)

Dome trap (open)

No. of crabs at entrance

30

30

No. of crabs entering

19

30

No. of attempts (avg. and range)

13 (2-45)

1.3 (1-4)

Time to entry (avg. and range)

12.3 (0.31-54.90)

2.0 (0.05-28.05)

From the behavior observations it was found that the shape of the trap and design of the entrances greatly affect the ingress rates of the target crabs. Open funnel entrances fitted in dome traps were more easily encountered because the crabs searched larger areas around the perimeter of the trap. Once at the entrance, all the crabs could ingress the trap by naturally crawling sideways in the direction of the bait. Conversely, the search areas around the box traps were smaller, and in several cases the crabs could not locate an entrance during their excursions; in addition, after reaching the entrance, the netting material and narrow slits hindered their ingress efforts and resulted in many crabs giving up. After completing the observations on crab behavior around traps of different designs and elucidating some of the factors influencing their capture process, comparative fishing trials were required to test catching performance and to determine which trap design was best for capturing swimming crabs.

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Fishing Trials To test the previous behavioral results, preliminary fishing trials were conducted in a large pond using box and dome traps (Vazquez Archdale and Kuwahara 2005). Unexpectedly, the catch of the box traps was more numerous than that of the dome traps, and this was attributed to differences in mesh size, entrance type and possibly the escape rates of the captured organisms from both trap designs. After conducting additional trials it was found that though the box traps caught many more crabs, most of them consisted of the small four-lobed swimming crab T. sima, which is of no commercial value, and many non-target organisms (Vazquez Archdale et al. 2006b) (Table 6). On the other hand, the dome trap captured exclusively commercial sized swimming crabs of carapace widths (CW) larger than 8 cm and hardly anything else. This demonstrates the superiority of the dome trap design for commercial harvesting of swimming crabs.

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Table 6. Catches of crabs and non-target organisms according to trap type

Catch Four-lobed swimming crab Shore swimming crab Blue swimming crab Total swimming crab Other crustaceans Moray eel Rockfish Catfish Goby Damselfish Snail Octopus Others Non-target organisms No. of traps Non-target organisms/trap

Box trap 344 33 13 390 (0.72) 7 3 5 61 11 1 51 5 6 150 (0.28) 100 1.5

No. of organisms (proportion) Mean Mean CW cm Dome trap CW cm 5.5 8.7 12.6

5 14 57 76 (0.95) 2

2 4 (0.05) 100 0.04

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6.7 8.6 12.4

Development of Trapping Gear and Methods for Swimming Crabs

43

The entrances fitted in the box traps close after an animal pushes through the tight slit acting as a one-way valve, making it impossible for any organism to escape from inside. The catch from dome traps was almost exclusively composed of large commercial swimming crabs, with hardly any non-target organisms. This contrasts with the results obtained with the box traps, which caught many undersized crabs and non-target species. This finding confirms the great selectivity of the dome design for harvesting commercial sized swimming crabs. After conducting the fishing trials with the different trap designs and determining their entry rates, a main cause for concern was the possible negative effect that lost traps might cause in the fishing ground. Lost traps continue to fish unattended for many years, which is called “ghost fishing”, and this results in considerable damage to existing fisheries resources. For this reason it was considered necessary to evaluate the escape rates from the traps employed and estimate their possible negative effects.

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Escape from Traps Box and dome trap designs containing crabs were set in a pond and their escape rates were ascertained during a 7-day period (Vazquez Archdale et al. 2007). Individual swimming crabs were marked and placed inside the different traps and escape rates were observed while diving. In several cases octopuses were found to be interfering with some of the traps, as confirmed by their presence together with the crab remains. For this reason complementary observations were conducted in a large tank by placing crabs inside traps, and subjecting them to a 7-day observation period. Escape results showed similar trends in both the pond and tank; crabs could not escape from box traps, as a consequence of their inability to separate the netting panels forming the slit entrance to exit the trap. On the other hand, the open funnel entrances of the dome trap permitted escape easily, and this was more pronounced in the pond than in the tank, where crab recluses were subjected to more outside stimuli. Average residence times for the 7-day observation period were 6.33 days for the blue swimming crab P. pelagicus and 6.83 for the shore swimming crab C. japonica inside the box trap, but only 0.30 days and 2.61 days in the dome trap, respectively (Table 7). Results obtained during the tank experiment using C. japonica were similar, with full 7-day residence in the box trap, but only averaging 4.8 days in the dome trap.

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From these findings it was concluded that a box trap lost at sea would continue to fish for up to 10 years, which is the average lifetime of a trap according to fishers, while the animals caught inside become bait and attract new ones into the trap. On the other hand, the dome design has open funnel entrances, and will allow crabs and other organisms to escape through them after the original bait is consumed. Consequently, the dome trap proves to be the best design; it catches the most swimming crabs and, if lost at sea, it will not kill so many organisms by ghost fishing and will conserve the existing fisheries resources.

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Table 7. Escape rates for swimming crabs according to trap type during 7 days

Organism Blue swimming crab Initial no. of crabs in traps No. of crabs remaining after 7 days No. of crabs disappearing Average days in trap Escape rate (%) Shore swimming crab Initial no. of crabs in traps No. of crabs remaining after 7 days No. of crabs disappearing Average days in trap Escape rate (%)

Box trap (slit entrances)

Dome trap (open funnels)

9 8 0 (1*) 6.33 0 (0%)

10 0 10 0.3 1 (100%)

23 22 0 (1*) 6.83 0 (0%)

23 5 18 2.61 0.78 (78%)

*indicates that the crab loss was due to octopus predation

CONCLUSION There are still considerable possibilities for improving current crab fishing practices. By applying the findings of chemoreception research, the effectiveness of conventional fish baits could be almost doubled with the simple addition of small sections of sugarcane. The selectivity potential of the bait was also demonstrated by adding sugar to the fish mince teabags, which maintained the catches of blue swimming crabs P. pelagicus but reduced those of other crab species. In the future, determining the taste preferences of the target organisms could help design species-specific bait. This new “designer”

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Development of Trapping Gear and Methods for Swimming Crabs

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bait would considerably reduce the number of non-target organisms in the catch, and the handling damage and stress they are subjected to while they are in the traps. Trap design profoundly affected the number of crabs found in the catch. Round or oval based traps enhanced crab exploration around their perimeter, and consequently increased the probability of crabs encountering an entrance that would lead them to the bait found inside. Entrance design was crucial as well; tight slit entrances prevented escape but at the same time hindered entry into the traps. The netting material forming the slits tangled with the spines on the carapace and appendages of the crabs, and restricted their forward movement into the traps. Open funnel entrances were much better because they did not obstruct crab passage and facilitated access towards the bait. This entrance type allowed for easy entry but also permitted escape. Escape has been blamed for decreasing a trap’s performance, but recently, as the negative consequences of lost traps by ghost fishing have been documented, the need for escape mechanisms has been recognized. Traps containing sufficient bait quantity will keep the crabs caught inside satisfied until they are hauled, and escape will not be a problem until a considerable time has passed. The dome trap with open funnel entrances proved to be the best design for commercial exploitation. In the future, other ways to improve its design might be to increase the number of entrances to facilitate entry. In extreme cases, fitting the entrances with escape preventing devices could be applied to improve crab retention; soft-eyed entrances or triggers might be installed. During fishing operations the loss of some trapping gear is inevitable, for this reason fitting all traps with ghost fishing prevention biodegradable panels that disintegrate with time, or installing time releases that open some part to make the trap non-operational should be mandatory.

ACKNOWLEDGMENTS The author is grateful to Mrs. Rebecca Finnis and Mrs. Hazel Archdale for their valuable time and great improvements on the original manuscript, and Dr. Gunzo Kawamura, from the Borneo Marine Research Institute, Universiti Malaysia Sabah, for his constant support.

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REFERENCES Ache, B.W. Chemoreception and thermoreception. In: Atwood, H.L. & Sandeman, D.C. The biology of crustacea (vol 3). New York: Academic Press; 1982; 369-398. Anonymous (1986). Simpler and more effective modernized methods: Pot fishing. Yamaha Fisheries Journal 27,1-8. Archdale, M.V. & Nakamura, K. (1992). Responses of the swimming crab Portunus pelagicus to amino acids and mono- disaccharides. Nippon Suisan Gakkaishi, 58, 165. Anraku, K., Vazquez Archdale, M., Mendez Cortes, B. & Espinosa R.A. (2001). Crab trap fisheries: capture process and an attempt on bait improvement. University of the Philippines in the Visayas Journal of Natural Sciences, 6, 121-129. Carr, W.S.E. The molecular nature of chemical stimuli in the aquatic environment. In: Atema, J., Fray, R.R., Popper, A.N. & Travolga, W.N. Sensory biology of aquatic animals. New York: Sprinter-Verlag Inc.; 1988, 3-27. FAO (2004). Yearbook - Fisheries statistics. Capture production. Vol 94/1. Rome. 642pp. Furevik, D.M. Behavior of fish in relation to pots. In: Ferno, A. & Olsen, S. Marine fish behavior in Capture and abundance estimation. London: Fishing News Books; 1994; 28-44. Kawamura, G., Matsuoka, T., Tajiri, T., Nishida, M. & Hayashi, M. (1995). Effectiveness of sugarcane-fish combination as bait in trapping swimming crabs. Fisheries Research, 22, 155-160. Kim, D. & Ko, K. (1987). Fishing mechanisms of pots and their modification. 2. Behavior of crab Charybdis japonica, to net pots. Bulletin of the Korean Society of Fisheries Technology, 20, 348-354. Kono, H., Shibukawa, K., Taki, Y., Takeda, M., Doi, A. & Moeki, M. (1999). Encyclopedia of Fish and Seafood, Vol. 1: Shrimps, Crabs and Fish. Heibonsha Co., Tokyo. (In Japanese) Krouse, J.S. (1989). Performance and selectivity of trap fisheries for crustaceans. In: Caddy, J.F. (Ed), Marine invertebrate fisheries: their assessment and management. John Wiley and Sons, New York, N.Y., pp. 307-325. Morioka, Y. Kitajima, C. & Hayashida, G. (1988). Oxygen consumption, growth and calculated food requirement of the swimming crab Portunus

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trituberculatus in its early developmental stage. Nippon Suisan Gakkaishi, 54(7), 1137-1141. Sakai, T. (1976). Crabs of Japan and the Adjacent Seas. Kodansaha Ltd.,Tokyo. Stephenson, W. & Campell, B. (1959). The Australian portunids (Crustacea: Portunidae) III. The genus Portunus. Aust .J. Mar. Freshwater Res., 10, 84-124. Takeda M. (1983). Systematics, Ecology and Development of Crabs. In: Sakai, T., Tomiyama, T., Hibiya, T., Takeda, M. (Eds.), Fisheries in Japan: Crab. Japan Marine Products Photo Materials Association, Tokyo. Thomson, J.M. (1951). Catch composition of the sand crab fishery in Moreton Bay. Aust. J. Mar. Freshwater Res., 2, 237-244. Vazquez Archdale, M., Anraku, K., Yamamoto, T. & Higashitani, N. (2003). Behavior of the Japanese rock crab “Ishigani” Charybdis japonica towards two collapsible baited pots: Evaluation of capture effectiveness. Fisheries Science, 69, 785-791. Vazquez Archdale, M.F. & Kuwahara, O. (2005). Comparative fishing trials for Charybdis japonica (A. Milne Edwards) using collapsible box-shaped and dome-shaped pots. Fisheries Science, 71, 1229-1235. Vazquez Archdale, M, Kariyazono, L. & Añasco, C.P. (2006a). The effect of two pot types on entrance rate and entrance behavior of the invasive Japanese swimming crab Charybdis japonica. Fisheries Research, 77, 271-274. Vazquez Archdale, M., Añasco, C.P. & Hiromori, S. (2006b). Comparative fishing trials for invasive swimming crabs Charybdis japonica and Portunus pelagicus using collapsible pots. Fisheries Research, 82, 50-55. Vazquez Archdale, M., Añasco, C.P., Kawamura, Y. & Tomiki, S. (2007). Effect of two collapsible pot designs on escape rate and behavior of the invasive swimming crabs Charybdis japonica and Portunus pelagicus. Fisheries Research, 85, 202-209. Vazquez Archdale, M., Añasco, C.P. & Tahara, Y. (2008). Catches of swimming crabs using fish mince in “teabags” compared to conventional fish baits in collapsible pots. Fisheries Research, 91, 291-298. Williams, M.J. (1982). Natural food and feeding in the commercial sand crab Portunus pelagicus Linnaeus, 1766 (Crustacea: Decaposa: Portunidae) in Moreton Bay, Queensland. J. Exp .Mar .Biol. Ecol., 59, 165-176.

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In: Crabs: Anatomy, Habitat, Editors: K. Saruwatari, M. Nishimura

ISBN: 978-1-61942-225-4 © 2012 Nova Science Publishers, Inc.

Chapter 3

DISTRIBUTION AND HABITAT OF COLD WATER CRAB SPECIES ON THE GRAND BANK OF NEWFOUNDLAND Darrell R. J. Mullowney*, Elaine M. Hynick, Earl G. Dawe and William A. Coffey Copyright © 2012. Nova Science Publishers, Incorporated. All rights reserved.

Science Branch, Fisheries and Oceans Canada, Northwest Atlantic Fisheries Centre, St. John’s, NL, A1C 5X1, Canada

ABSTRACT New technologies in ocean mapping have allowed for improved classification of bottom substrate and three-dimensional views of the ocean floor. The Department of Fisheries and Oceans Canada (DFO) has been opportunistically collecting three-dimensional bottom classification data on research surveys along the Newfoundland and Labrador (NL) continental shelf for 17 years, with the Grand Bank off Newfoundland’s southeast coast presently most comprehensively mapped. The Grand Bank is comprised of diverse habitats, including a cold thermal regime across the shallow northern portion which is dominated by hard bottom substrates, and warmer regimes on the southern portion and deeper slope edges which are characterized by a variety of bottom substrate types. Several species of crabs inhabit the Grand Bank ecosystem, ranging from *

Corresponding Author: Darrell Mullowney; phone (709) 772-2521; fax (709) 772-4105; email: [email protected]

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Darrell R. J. Mullowney, Elaine M. Hynick, Earl G. Dawe, et al. large, commercially important and extensively studied species such as the Snow Crab (Chionoecetes opilio), to small species such as Hermit Crabs (Pagurus spp.) for which little is known. In this chapter, we utilize data from spring and fall multi-species trawl surveys routinely conducted across the Grand Bank from 1995-2010 to investigate the distribution and habitat preferences of all crab species inhabiting the region. We examine the distribution of each species in relation to bathymetry and thermal regime, and for the first time incorporate bottom classification information to examine the habitat preferences of each species in a nearvirtual fashion.

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INTRODUCTION With a shallow-water expanse covering more than six degrees of both longitude and latitude, the Grand Bank off Newfoundland’s southeast coast is the largest fishing bank in the northwest Atlantic. Historically, the Grand Bank supported some of the world’s largest groundfish fisheries, but interest in other fisheries grew following the collapse of groundfish stocks in the early 1990s. In the modern context, the Snow Crab (Chionoecetes opilio) fishery is the largest and most valuable fishery on the Grand Bank in terms of socioeconomics. Much of the historical scientific focus on the Grand Bank region has been on finfish species, and with the exception of increased recent interest in Snow Crab and Northern Shrimp (Pandalus borealis), comparatively little research has been conducted on crustaceans. In this chapter, we investigate and document the habitat and distribution of all crab species known to inhabit the Grand Bank ecosystem. We investigate their spatial and thermal habitat characteristics and capitalize on new mapping technologies to examine the distribution of each species by substrate type. This chapter constitutes a significant addition to the currently limited volume of information for most crab species occurring in offshore regions of the Newfoundland Shelf. The species diversity of crabs on the Grand Bank is low. In total, nine species of seven different genera are known to inhabit the Bank. It is possible other species occur in the area, especially with the recent introduction of new species such as the invasive European Green Crab (Carcinus maenas) (Blakeslee et al., 2010) and the Gladiator Box Crab (Acanthocarpus alexandri) (Mullowney et al., 2011a) into adjacent NL waters. The following sections briefly detail pertinent distinguishing and biological characteristics of each crab species known to inhabit the area.

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Hermit Crabs: Hermit crabs are not ‘true’ crabs of the infraorder Brachyura; rather, they belong to the infraorder Anomura, which exhibit a reduced and asymmetrical abdomen veiled under the thorax. The soft and irregularly shaped abdomens of Hermit Crabs are adapted for intrusion into shells. The soft abdomens render Hermit Crabs vulnerable to predation, so they conceal themselves in empty shells or other rigid structures along the seafloor. Two species of Hermit Crabs are known to occur on the Grand Bank; Pagurus pubescens and Pagurus arcuatus (Squires, 1990). However, it is possible that other species such as Pagurus acadianus, which occupy inshore waters of Newfoundland, could be present. Pagurus pubescens are generally reddish in colour with light brownish legs (Figure 1), and may reach a size of 10-14mm along the anterior shield. They are distributed throughout the northwest Atlantic from George’s Basin in the south to Baffin and Hudson Bays in the north (Squires, 1990) in waters ranging from -1.6 to 4.6°C (Williams, 1984). Pagurus arcuatus are pink to dull white in colour (Figure 1), and can reach sizes of 15mm in length along the anterior shield for males and 8mm for females (Squires, 1990). They are distributed from the Virginia Capes in the south to West Greenland in the north (Squires, 1990) in depths ranging from 0 to 270m (Williams, 1974). There are no commercial fisheries for Hermit Crabs along the Grand Bank or any other part of Newfoundland. Hyas Crabs: Hyas Crabs are true Brachyuran crabs of the family Majidae, which are commonly termed ‘Spider Crabs’. The distinguishing features of Hyas Crabs include an elongated triangular to pear-shaped carapace with ‘hooks’ on both sides of the head. Two species of Hyas Crabs are commonly captured on the Grand Bank; Toad Crabs (Hyas araneus) and Arctic Toad Crabs (Hyas coarctatus). Toad Crabs can reach sizes as great as 95mm and 81mm carapace length (CL) for males and females respectively (Williams, 1984). They are normally a dull reddish brown dorsally and pale off-white ventrally (Figure 1; Squires, 1990). The species occurs from the northeastern seaboard of the United States (U.S.) in the south to northern Labrador in the north, inhabiting waters of -1.3 to 6.3°C. They are normally captured in depths ranging from about 35-730m (Squires, 1990). Arctic Toad Crabs appear to be more tolerant of cold water than Toad Crabs. In the northwest Atlantic, Arctic Toad Crabs are distributed from the U.S. Eastern Seaboard in the south to the northern extremes of Hudson Bay in the north and can be captured at depths ranging from 0-550m (Squires, 1990). The species is normally a dull reddish colour dorsally and a light buff to off-white ventrally (Figure 1). Maximum size for Arctic Toad Crabs is smaller than Toad Crabs, with males reaching about 87mm CL and females about 49mm CL (Squires,

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Darrell R. J. Mullowney, Elaine M. Hynick, Earl G. Dawe, et al.

1990). There are small-scale commercial fisheries for ‘Toad’ Crabs in inshore regions of NL which retain both species. However, there is no commercial prosecution for either species on the Grand Bank. Snow Crab: Snow Crab (Chionoecetes opilio) are Brachyuran Crabs of the family Majidae. In the northwest Atlantic, they are found from the Gulf of Maine to West Greenland, with a single genetic stock complex extending throughout the distributional range (Puebla et al., 2008). Snow Crab exhibit strong sexual dimorphism in physical characteristics. In Newfoundland, males may reach 150mm carapace width (CW) while females may reach about 95mm CW. Dorsally, these crabs are generally brownish in colour (Figure 1), but the carapace can contain reddish or greenish tinges. Ventrally, they may be white, yellow or brown depending on time elapsed since last molt. The species is captured over a broad depth spectrum, but most crabs occur at depths ranging from about 70-300m (Elner, 1985). The species is restricted to cold water regions, with temperatures above 7°C representing a threshold whereby the metabolic load exceeds the capacity for caloric intake (Foyle et al., 1989). In some regions, migratory movements appear driven by temperature, with ontogenetic migrations toward deeper, warmer water as crabs age (Orensanz et al., 2004). Only males greater than 95mm CW are targeted by the fishery. With approximately 3,200 licence holders fishing Snow Crab in NL in recent years, and a quota ranging from 46,000 – 62,000t since 1998 (Dawe et al., 2010a), the NL snow crab fishery is the largest in the world (Mullowney et al., 2011b). Furthermore, with annual landings of 22,000-26,000t since 1999, the Grand Bank fishery represents the largest single-source of landings in the region. Table 1. Sample sizes (total catch) for each species group

Group Hermit Hyas Snow Cancer Spiny Brown Spiny Red

number 618 98,038 243,390 136 722 190

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Pagurus pubescens Source: Sciencelibrary.com

Hyas coarctatus Source: Sealifebase.org

Pagurus arcuatus Source: Superstock.com

Hyas araneus

Chionoecetes opilio Source: DFO.ca

Cancer borealis

Figure 1. (Continues)

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Cancer irroratus Source: Superstock.com

Neolithodes grimaldii Source: Dwayne Pittman (DFO)

Lithodes maja

Figure 1. Images of crab species captured on the Grand Bank.

Table 2. Global Index of Collocation for each species group (% horizontal overlap)

Snow Hyas Hermit

Spiny Spiny Spiny Spiny Spiny Cancer Brown - 1 Brown - 2 Brown - 3 Brown - 4 Red - 1

Spiny Red - 2

Spiny Red - 3

Spiny Red - 4

50.1

65.8

42.6

58.4

35.1

27

27.6

36.2

38.1

Hyas

Hermit

96.6

0

38.8

53.5

63.3

35.8

40.6

73

31.2

30.4

35.8

22.5

60.5

15.9

25

36

61.3

13.2

16.8

66.8

43.2

Cancer

3.7

3

7

95

1.8

3.2

61

4.5

Spiny Red - 1

64.2

2.7

0.9

4

Spiny Red - 2

28.2

27.3

3.6

5.2

Spiny Red - 3

8

13.1

45.9

57.2

Spiny Red - 4

5

7.5

8.2

9.6

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Cancer Crabs: Cancer crabs are true Brachyuran crabs of the family Cancridae. Among their distinguishing characteristics are strong, proportionately large claws and broad, oval-shaped carapaces with marginal teeth along the anterior edges. Two species of Cancer Crabs are found on the Grand Bank; Jonah Crabs (Cancer borealis) and Rock Crabs (Cancer irroratus). Jonah Crabs are distributed in the western Atlantic from Florida to the Grand Bank (Squires, 1990), in depths ranging from 0-800m (Williams, 1984). They are generally reddish brown dorsally and pale yellow ventrally (Figure 1), and may reach sizes as large as 180mm CW for males and 152mm CW for females (Elner, 1985). There are small-scale commercial fisheries for Jonah Crab in some areas of Atlantic Canada but no commercial exploitation occurs on the Grand Bank. Rock Crabs are normally similar in colour to Jonah Crabs, but can be cryptic in shallow areas, exhibiting colour variations to blend in with their surroundings (Figure 1; Squires, 1990). They can reach sizes as large as 125mm and 91mm CW for males and females respectively (Elner, 1985). Similar to Jonah Crabs, Rock Crabs are broadly distributed in the western Atlantic, from Florida in the south to southern Labrador in the north (Squires, 1990) and are found at depths ranging from 0-575m (Williams, 1984). Rock Crabs are commercially fished in inshore regions of Newfoundland, but not on the Grand Bank. Spiny Brown Crab: Spiny Brown Crabs (Lithodes maja) are not true Brachyuran Crabs; rather, they are grouped with Hermit Crabs in the infraorder Anomura. In Newfoundland, they are also commonly referred to as “Northern Stone Crab”. Crabs of the genus Lithodes are commonly referred to as “King Crabs”. Female Spiny Brown Crabs exhibit an asymmetrical abdomen, but unlike Hermit Crabs, the abdomens of Lithodes Crabs are generally leather-like or heavily calcified. The entire dorsal surface of the Spiny Brown Crab is covered with short spines, with the longest spines occurring along the carapace edges (Figure 1). The colouration can be highly variable, ranging from red to brownish-purple dorsally, while ventrally they are normally a pale-yellow (Squires, 1990). In many areas of the Grand Bank, there is often a striped appearance in colouration, and different parts of the animal can exhibit different colour patterns. The species occurs in northern latitudes of both the western and eastern Atlantic. In the western Atlantic, the range spans from New Jersey in the south to the lower portions of Baffin Bay in the north (Squires, 1990). They are found at depths ranging between 65790m (Williams, 1984). Males can reach sizes as large as 105mm CL, and females about 80mm CL (Squires, 1990). There have been small-scale

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experimental fisheries for this species in various parts of NL but no targeted exploitation occurs on the Grand Bank. Spiny Red Crab: Spiny Red Crabs (Neolithodes grimaldi) are not true crabs. Like other species of the infraorder Anomura, they exhibit the typical asymmetrically shaped abdomen, especially in females. The distinguishing features of this species are the bright red colouration throughout and the long, sharp dorsal spines (Figure 1). In Newfoundland, they are also referred to as “Porcupine Crab”. Information on this species is lacking, likely because it occurs in depths beyond those commonly fished. It occurs on both sides of the north Atlantic. In the western Atlantic it is distributed from North Carolina in the south to Greenland in the north at depths ranging from 800-2000m (Squires 1990). The species can reach sizes as large as 120-130mm CL (Squires, 1965). There are no commercial fisheries for this species in NL.

METHODS

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Specimen and Temperature Collections Data on the abundance and distribution of each crab species were acquired from multi-species trawl surveys conducted along the Grand Bank each spring and fall from 1995 to 2010, with the exception of spring 1995. The spring surveys generally occurred in May and June while the fall surveys occurred in October and November in most years. The surveys utilized a Campelen 1800 shrimp trawl to sample randomly selected stations across a depth-stratified design (Doubleday, 1981), with the number of sets allocated to each stratum proportional to size. The tows were standardized to 15 minutes duration at a speed of 3.0 knots. The strata in the Northwest Atlantic Fisheries Organization (NAFO) Divisions 3LNO, which encompasses the Grand Bank, extend to 1,463m, but depths exceeding 750m were not surveyed in all years, including most recent years, as these deep strata are normally the first to be omitted if mechanical, logistical, or other issues occur during the survey. The catch from each tow was sorted by species and quantified at sea, with sub-sampling employed in the event of large catches. For important commercial species, such as Snow Crab, further detailed sampling of biological parameters such as size and maturation was conducted. However, as all other crab species did not receive detailed biological sampling, we limited all analyses to numbers per

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tow for each species. Furthermore, there was taxonomic ambiguity in the data with respect to classification of several crab species. To account for this, we grouped several species to the genus level. Specifically, Toad Crabs (Hyas Araneus) and Arctic Toad Crabs (Hyas coarctatus) were grouped as “Hyas” Crabs, Rock Crabs (Cancer irroratus) and Jonah Crabs (Cancer borealis) were grouped as “Cancer” Crabs, and both Pagurus spp. were grouped as “Hermit” Crabs. All other species were analyzed at the species level. The catchability of the survey trawl for most species of crabs is unknown, but assumed to be low. Catchability (q) is an index that ranges from 0 to 1; in this case it represents the proportion of crabs that are successfully captured when ran over with a trawl. Dawe et al. (2002) studied the catchability for Snow Crab, and found it to be much lower than 1 and highly variable depending on crab size and substrate type. Catchability decreased with crab size and was lowest on hard substrates. Bottom temperature data used in this study were collected during the multi-species surveys using a trawl-mounted conductivity temperature and depth (CTD) system.

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Bottom Classification DFO has opportunistically collected three-dimensional bottom classification data from three research vessels conducting surveys (scallop, snow crab, spring & fall multi-species trawl) along the Newfoundland and Labrador continental shelf since 1995. Presently, the Grand Bank in NAFO Divsions 3LNO is most comprehensively mapped because this area is surveyed by the multi-species research surveys in both spring and fall, whereas all other areas receive only a spring or fall survey. During research trips, the SeaScan and RoxAnn bottom discrimination systems run continuously, profiling depth and bottom characteristics using hull mounted acoustic transducers. The nature of the seabed is assessed through the first (E1) and second (E2) echo returns. The E1 measures the signal strength from the oblique back-scatter of the first echo return, giving a roughness parameter, and the E2 measures the second or double reflection from the sea surface, giving a hardness parameter. In combination, these two indices provide an unambiguous signature for most seabed types ranging from mud to bedrock. As the data collection is opportunistic, some areas can be profiled several times while other areas may only be profiled once. Therefore, for areas that were only profiled once, we assumed the nature of the seabed has changed

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Darrell R. J. Mullowney, Elaine M. Hynick, Earl G. Dawe et al.

little over time upon compiling the data into a composite view of the seafloor on the Grand Bank.

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Data Analysis To examine the relationship of bottom temperature with depth along the Grand Bank, we plotted individual observations of temperature and depth from each trawl set. We fit a 50m running average of temperature to the data to discern a clear relationship. To examine the relationship of each species with depth and temperature, we used simple box and whisker plots, examining median depths for each species with the interquartile range (IQR) represented by Q1 and Q3, or the twenty-fifth and seventy-fifth percentiles of the data, and the whiskers extending to minimum and maximum values. The percentages of crabs captured by bottom type were quantified for Snow Crabs, Hyas Crabs, Spiny Brown Crabs, and Cancer Crabs, grouping substrate types simply as ‘hard’ versus ‘soft’. Data were insufficient to quantify the bottom type in areas of capture for the other species. The soft substrate types included mud, sand, and sand/shell, while the hard substrate types represented gravel, rock, and bedrock. To assess the spatial interconnectivity of each species, we plotted the spatial distribution of abundance (catch rates = #/tow) for each species, using expanding symbols to represent increasing catch rates based on 4 grouped catch rates of 0-10, 11-25, 25-100, and >100 crabs per tow. We quantified spatial overlap utilizing a Centre of Gravity (CG) and Global Index of Collocation (GIC) approach (Woillez et al., 2007, 2009). The CG represents the mean location of the population based upon the mean location of an individual crab taken at random in the study area. Inertia describes the dispersion of each species around the CG based upon the mean square distance between an individual crab and the CG. The GIC is an index ranging from 0 to 1 which describes the level of geographic (horizontal) overlap between distinct populations by comparing CGs and the mean distances between individual crabs taken independently at random from a population. A GIC of 0 would constitute no overlap while a GIC of 1 would constitute complete overlap. Upon initial investigation we identified distinct patches of abundance for Spiny Brown and Spiny Red Crabs and found them to bias the CGs and GICs for these species. Accordingly, we treated each aggregation individually in assessing the degree of overlap with other species. We deemed the distribution

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of Hermit Crabs to be homogenous, albeit sparse, and the distributions of Snow, Hyas, and Cancer Crabs to be continuous without discrete breaks, so we treated these populations as a whole in developing the CG and GIC indices. We transformed the GIC to a percentage overlap for tabulation of results.

Figure 2. Bottom substrate profile of the Grand Bank.

RESULTS Shallow areas on the Grand Bank are generally comprised of harder substrates than the slope edges, which tend to be dominated by mud and sand (Figure 2). The substrate composition atop the Bank is patchy in nature, with sand/shell and gravel dominating. Some small patches of rock occur atop the

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Darrell R. J. Mullowney, Elaine M. Hynick, Earl G. Dawe et al.

Bank, such as in the northeastern corner, as well as isolated muddy holes, most common in northern and western areas. The Grand Bank is generally a cold environment (Figure 3). On average, the bottom temperature atop the Bank decreases from about 3.5°C at 30m to about 0°C or slightly colder at 175 to 200m. Temperature increases abruptly at 200m, with temperatures in the 200-225m depth interval averaging about 2°C. From 225-400m, along the shelf break, there is a gradual increase in bottom temperature, up to about 4°C. There is little change at greatest depths, with all depths below 400m averaging 3.5 to 4°C. Although cold water dominates, there are some isolated areas of warm temperature on the Grand Bank, as seen by the scatter of occasional readings of 4 to 9°C in waters as deep as 600m (Figure 3). Snow and Hyas Crabs were the most abundant (Table 1) and widely distributed species on the Bank (Figure 4). The catches of all other species were comparatively low (Table 1). There was a high degree of horizontal overlap in the distributions of Snow and Hyas Crabs (96.6%; Table 2), but a distinct segregation between the areas of highest abundance for these two species (Figure 4), with dense aggregations of Snow Crab more common near the periphery and dense aggregations of Hyas Crabs largely restricted to the central portions of the Bank. The CG was similar for both species groups, located near the centre of the Bank (Figure 5, Table 3). Hermit Crabs were less widely distributed and there were no large catches of this species group. They were most common in southern areas (Figure 4), as indicated by a CG located centrally in the southern half of the Bank (Figure 5, Table 3). Hermit Crab distribution was most greatly horizontally overlapped with Hyas Crabs (Table 2), although there was little association between the distribution of Hermit Crabs and dense aggregations of Hyas Crabs (Figure 5). Spiny Brown and Cancer Crabs were most common along the southwestern slope of the Bank (Figure 4), although Spiny Brown Crabs also occurred in other deep locations, most notable along the southeast slope. Spiny Red Crabs were also captured along the southwest slope, as well as in other deep regions, especially in the northeast corner near the ‘Nose’ of the Bank. There was a very tight horizontal spatial overlap between Cancer and Spiny Brown Crabs along the southwest slope as indicated by near identical CGs (Figure 5, Table 3). Otherwise, the level of overlap among Cancer, Spiny Brown, and Spiny Red Crabs on the slope edges was minimal, with discrete pockets of Spiny Brown and Spiny Red Crabs occurring around the perimeter of the Bank (Figure 5).

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Temperature (°C)

Distribution and Habitat of Cold Water Crab Species ... 10 9 8 7 6 5 4 3 2 1 0 -1 -2 0

200

400

600

800

1000

1200

1400

Depth (m)

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Figure 3. Temperature versus depth on the Grand Bank. Black line indicates the 50m running average temperature.

Figure 4. Distribution of abundance for each species group of crabs. Catch rates (# / tow) scaled as follows: purple dots (1-10), red circles (11-25), light blue circles (26100), dark blue circles (>100).

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Darrell R. J. Mullowney, Elaine M. Hynick, Earl G. Dawe et al. Table 3. Centre of Gravity co-ordinates for each species group (DDMM.M)

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Group Hermit Hyas Snow Cancer Spiny Brown-1 Spiny Brown-2 Spiny Brown-3 Spiny Brown-4 Spiny Red-1 Spiny Red-2 Spiny Red-3 Spiny Red-4

Latitude 4455.2 4613.4 4627.2 4406 4827.1 4555 4322.2 4414.1 4843.9 4705 4328.9 4443.4

Longitude 5120.7 5059.5 5010.3 5249.4 4830.9 4742.8 4921 5308.6 4926.4 4656.8 5125.9 4851.9

Most crabs were captured in shallow water (Figure 6). Hermit Crabs were distributed the shallowest of all species, with an IQR from 64-113m and a median depth of 74m. The majority of Snow and Hyas Crabs were captured in waters ranging from about 75 to 200m depth. The depth distribution of Cancer Crabs exhibited a positive skew, with the median of 234m occurring near Q1, at 197m, and the IQR extending as deep as 413m. Spiny Brown Crabs were relatively evenly distributed from about 230m (Q1) to 495m (Q3), with a centralized median at 340m. Spiny Red Crabs were found much deeper than all other species, captured at a median depth of 1,067m and an IQR spanning from 872-1,229m. Hermit Crabs were most commonly captured in 1 to 4°C waters, with a median at 2.3°C (Figure 7). Hyas and Snow Crabs were distributed in the coldest waters of all species on average, with medians of 0.4 and 0.5°C respectively. Both species had a Q1 of -0.3°C, but the IQR of Snow Crab extended to slightly warmer temperatures, with the Q3 of 2.4°C a full degree warmer than that of Hyas Crabs. Cancer, Spiny Brown, and Spiny Red Crabs were captured in warmer waters. The temperature distribution of Cancer and Spiny Brown Crabs was similar, with medians at 5.4 and 5.2°C respectively.

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Both species showed little tolerance for temperatures below 4°C (Q1), and exhibited upper bounds of 6-7°C at Q3. Spiny Red Crabs showed little variation in temperature distribution as they were captured almost exclusively over a very narrow temperature range of 3.4 - 3.9°C.

Figure 5. Centres of Gravity (CG) for each species group of crabs. Plus signs show CGs for each species/group. Radiant lines show inertia distribution for CGs to capture locations for each species. Note: No inertia lines shown for Snow or Hyas Crabs because of the widespread distributions. Numbers show CGs for discrete populations of Spiny Red and Spiny Brown Crabs.

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Darrell R. J. Mullowney, Elaine M. Hynick, Earl G. Dawe et al.

1500 1350 1200

Depth (m)

1050 900 750 600 450 300 150 0 Hermit

Hyas

Snow

Cancer

Spiny Brown

Spiny Red

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Figure 6. Box and whisker plots of the depth distribution of each species. Medians indicated by stars, boxes are Q1 and Q3, and whiskers extend to minimum and maximum values.

Most Snow and Hyas Crabs were captured on hard bottom, with approximately 70 and 90% of each species occurring on hard substrates respectively (Figure 8). Conversely, most Spiny Brown and Cancer Crabs were captured on soft bottom, with approximately 70% of both species occurring on soft bottom.

DISCUSSION AND CONCLUSIONS Despite a dynamic physical environment, the species diversity of crabs inhabiting the Grand Bank ecosystem is low. This may reflect the persistent cold conditions that occur along most portions of the Bank. The cold conditions are a function of the Cold Intermediate Layer (CIL), a cold water mass present at shallow and intermediate depths in regions of the northwest Atlantic. On the NL shelf, southerly flowing Arctic Water transported by the Labrador Current is advected in shallow regions atop the Grand Bank (Colbourne et al., 2010; Dawe et al., 2010b). The resultant cold water accumulation persists year round between 30-200m depths, as seen from

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Temperature (°C)

temperature collections taken from the spring and fall surveys. As most of the Grand Bank ecosystem is characterized by depths less than 200m, the majority of available habitat is very cold, with warm water habitat largely restricted to the spatially limited deep slope edges. 10 9 8 7 6 5 4 3 2 1 0 -1 -2 Hyas

Snow

Cancer

Spiny Brown

Spiny Red

Figure 7. Box and whisker plots of the temperature distribution of each species. Medians indicated by stars, boxes are Q1 and Q3, and whiskers extend to minimum and maximum values.

100 90 80 70 60 50 40 30 20 10 0

Soft (Mud - Sand/Shell) Hard (Gravel - Bedrock)

Percent (%)

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Hermit

Snow

Hyas

Brown Spiny

Figure 8. Distribution of species groups by substrate type.

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Cancer

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Darrell R. J. Mullowney, Elaine M. Hynick, Earl G. Dawe et al.

This chapter confirmed pre-existing information and led to the generation of new knowledge for most species of crabs examined. For Hermit Crabs, our findings fit well with the existing information on temperature and depth distribution (Squires, 1990), as we found these species inhabiting shallow regions of intermediate temperatures. On the Grand Bank, Hermit Crabs have little horizontal or vertical overlap with densest aggregations of other crab species. Their distribution is centred on the southern portion of the Bank. This is the shallowest portion of the Bank and is dominated by sand/shell and gravel substrates. Inhabiting the shallowest waters may allow Hermit Crabs to avoid the coldest waters of the CIL or minimize competition with other crabs. A preference toward sand/shell and gravel substrates is consistent with the distribution of P. pubescens in the Barents and White Seas (Sokolov, 2006) and other species of Hermit Crabs from other regions (Ayes-Perez and Mantelatto, 2008). This habitat likely best overlaps with that of shell-bearing gastropods, which may consequently allow Hermit Crabs the highest probability of finding suitable shells for protection, and remain conspicuous with their surroundings (Briffa and Twyman, 2011). The distribution of Hermit Crabs most greatly overlapped with Hyas Crabs, but relative to Hermit Crabs, dense aggregations of Hyas Crabs were captured more northerly and slightly deeper on average. The slight depth differential between these two species groups led to a large scale temperature differential, with nearly 2°C difference between the medians and little overlap of IQRs for the two groups. This indicates that Hyas Crabs were more commonly found within the cold waters of the CIL. With the exception of the southwest portion of the Bank, Hyas Crabs were distributed across nearly the entire surface of the Bank. However, there was a definite pattern of concentration at mid latitudes and longitudes, an area dominated by sand/shell and gravel. There is no known published literature specific to Hyas Crab substrate preference, but the description of diet for Hyas araneus in Squires (1990) includes hermit crabs, gastropods, and sea urchins; species which would be expected to be found on these substrates. In general, our results indicate that the habitat of Hyas Crabs is comprised of relatively shallow and very cold areas with sandy to gravel/rocky bottoms. Snow Crab on the Grand Bank occupy a niche comprised of intermediate depths and temperatures and a mixture of substrate types. The horizontal distribution of Snow Crabs was almost fully overlapped with that of Hyas Crabs. However, the densest aggregations of the two species groups were almost wholly segregated from one another. The slightly deeper average distribution of Snow Crab resulted in a warmer average temperature distribu-

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tion than Hyas Crab because more Snow Crab were distributed below 200m, in warmer waters beyond the CIL. Our finding of approximately 70% of Snow Crab being captured on hard bottom is not consistent with the fishing patterns for this species in NL, which targets deep, muddy substrates (Dawe et al., 2010a). The high percentage of crabs captured on hard bottom relates to the distribution of abundant small crabs, which generally occupy shallow, harder regions (Dawe and Colbourne, 2002). We feel that the deeper distribution of the fishery relative to our findings reflects an ontogenetic migration of Snow Crab on the Grand Bank. Similar to the Eastern Bering Sea population (Orensanz et al., 2004), there is evidence to suggest that Grand Bank Snow Crab migrate toward deeper, warmer water as they grow (Dawe and Colbourne, 2002). The horizontal distribution of Cancer and Spiny Brown Crabs overlapped considerably along the southwestern slope of the Bank. However, Spiny Brown Crabs were more widely dispersed, with smaller discrete populations found along other slope edges and a more extensive north-south distribution along the southwest slope. Both species groups occupied a similar temperature range and were primarily captured on soft substrates. However, Spiny Brown Crabs tended to be captured deeper on average, indicating some vertical segregation of the two species groups. The southwest slope of the Grand Bank is a uniquely warm area because of the influence of adjacent warm offshore water masses associated with the Gulf Stream System. ‘Slope Water’ refers to a water mass that occupies the region between the offshore Gulf Stream and the continental shelf (McClellan et al., 1952) that occurs because of the confluence and mixing of the Labrador Current and Gulf Stream in this area (Gatien, 1976). Slope-water is primarily responsible for the uncharacteristiccally high temperature values we observed at some shallow and intermediate depths in our temperature profile. There is little information available on the specific thermal requirements for Cancer or Spiny Brown Crabs, but our results suggest both species groups are largely intolerant of temperatures below 4°C. It appears that Cancer and Spiny Brown Crabs in this area have found a unique niche habitat, predominately occupying a deep, warm, softbottomed habitat along the southwest slope of the Bank. Spiny Red Crabs had very little overlap with any other species. There was strong horizontal overlap with Spiny Brown and Cancer Crabs, but there was complete segregation by depth between these species as Spiny Red Crabs occurred much deeper, at depths of 900-1200m. The temperature at these extreme depths was very stable at 3.5-4°C. There is no literature available on the habitat requirements of Spiny Red Crabs. However, as shallower regions

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of slope edges are comprised of soft bottom likely suitable for habitation, it is reasonable to speculate this species is very temperature sensitive. This is supported by the fact that discrete pockets of this species were distributed in a very small temperature range with little variability. Among the most interesting outcomes of this chapter is how well the basic principles of ecology fit within a large-scale ecosystem such as the Grand Bank. Clearly, with little spatial overlap among most species of crabs, there is a high degree of habitat partitioning and niche selection occurring by crab species inhabiting this highly dynamic ecosystem.

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REFERENCES Ayres-Peres, L. and Mantelatto, F.L., 2008. Patterns of distribution of the Hermit Crab Loxopagurus loxochelis (Moreira, 1901) (Decapoda, Diogenidae) in two coastal areas of southern Brazil. Revista De Biologia Marina Y Oceanografia 43(2): 399-411. Blakeslee, A.M.H., McKenzie, C.H., Darling, J.A., Byers, J.E., Pringle, J.M., and Roman, J., 2010. A hitchhiker’s guide to the Maritimes: anthropogenic transport facilitates long-distance dispersal of an invasive marine crab to Newfoundland. Diversity and Distributions 16(6): 879-891. Briffa, M., and Twyman, C., 2011. Do I stand out or blend in? Conspicuousness awareness and consistent behavioural differences in Hermit Crabs. Biology Letters 7(3): 330-332. Colbourne, E.B, Craig, J., Fitzpatrick, C., Senciall, D., Stead, P., Bailey, W., 2010. An Assessment of the Physical Oceanographic Environment on the Newfoundland and Labrador Shelf in NAFO Subareas 2 and 3 during 2009. Northwest Atlantic Fisheries Organization Scientific Council Res. Doc. 10/16, 24p. Dawe, E., Mullowney, D., Stansbury, D., Hynick, E., Veitch, P., Drew, J., Colbourne, E., O’Keefe, P., Fiander, D., Skanes, K., Stead, R., MaddockParsons, D., Higdon, P., Paddle, T., Noseworthy, B., and Kelland, S., 2010a. An assessment of Newfoundland and Labrador Snow Crab (Chionoecetes opilio) in 2008. DFO Can. Sci. Advis. Sec. Res. Doc. 2010/016, iv + 183 p. Dawe, E.G., Mullowney, D.R., Colbourne, E.B., Han, G., Morado, J.F., and Cawthorn, R., 2010b. Relationship of oceanographic variability with distribution and prevalence of Bitter Crab Syndrome in Snow Crab (Chionoecetes opilio) on the Newfoundland-Labrador Shelf. In: Biology

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and Management of Exploited Crab Populations under Climate Change. Alaska Sea Grant, University of Alaska Fairbanks. doi:10.4027 /bmecpcc.2010.06 Dawe, E.G., McCallum, B.R., Walsh, S.J., Beck, P.C., Drew, H.J., and Seward, E.M., 2002. A study of the catchability of the Snow Crab by the Campelen 1800 survey trawl. DFO Can. Sci. Advis. Sec. Res. Doc. 2002/051, 15p. Dawe, E.G., and Colbourne, E.G., 2002. Distribution and demography of Snow Crab (Chionoecetes opilio) males on the Newfoundland and Labrador Shelf. In: Crabs in Cold Water Regions: Biology, Management, and Economics. Alaska Sea Grant College Program, AK-SG-02-01: 577593. Doubleday, W.G., 1981. Manual on groundfish surveys in the northwest Atlantic. Northwest Atlantic Fisheries Organization Scientific Council Studies: 2, 55p. Elner, R. W., 1985. Crabs of the Atlantic coast of Canada. DFO Underwater World Factsheet. UW/43: 8p. Foyle, T.P., O’Dor, R.K., and Elner, R.W., 1989. Energetically defining the thermal limits of the Snow Crab. J. Exp. Biol. 145: 371-393. Gatien, M.G., 1976. A study of the Slope Water Region south of Halifax. J. Fish. Res. Board Can. 33: 2213-2217. McClellan, H.J., Lauzier, L., and Bailey, W.B., 1952. The slope water off the Scotian Shelf. J. Fish. Res. Board Can. 10(4): 155-176. Mullowney, D.R., Dawe, E.G., Coffey, W.A., and Squires, H.J., 2011a. Northern range extension of the Gladiator Box Crab (Acanthocarpus alexandri) (Stimpson, 1871) (Decapoda: Brachyura: Calappidae) in the northwest Atlantic. J. Crus. Biol. 31(2): 374-376. Mullowney, D.R., Dawe, E.G., Morado, J.F., and Cawthorn, R.J., 2011b. Sources of variability in prevalence and distribution of bitter crab disease in Snow Crab (Chionoecetes opilio) along the northeast coast of Newfoundland. ICES J. Mar. Sci. 68(3): 463-471. Orensanz, J., Ernst, B., Armstrong, D.A., Stabeno, P., and Livingston, P., 2004. Contraction of the geographic range of distribution of Snow Crab (Chionoecetes opilio) in the eastern Bering Sea: An environmental ratchet? California Cooperative Oceanographic Fisheries Investigations Reports 45: 65-79. Puebla, O., Sevigny, J., Sainte-Marie, B., Brêthes, J., Burmeister, A., Dawe, E.G., and Moriyasu, M., 2008. Population genetic structure of the Snow

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Crab (Chionoecetes opilio) at the northwest Atlantic scale. Can. J. Fish. Aq. Sci. 65(3): 425-436. Sokolov, V.I., 2006. Distribution of two Hermit Crabs (Pagurus pubescens) and (P. bernhardus) (Anomura, Paguridae) in the Barents and White Seas. Zoologichesky Zhurnal 85(10): 1176-1186. Squires, H., 1965. Decapod crustaceans of Newfoundland, Labrador and the Canadian eastern Arctic. Fish Res. Board. Can. 21: 461-467. Squires, H., 1990. Decapod crustacea of the Atlantic coast of Canada. Can. Bull. Fish. Aq. Sci. 221, viii+532p. Williams, A.B., 1974. Marine flora and fauna of the northeastern United States Crustacea: Decapoda. NOAA Tech. Rep. NMFS Circ. 389: 50p. Williams, A.B., 1984. Shrimps, lobsters and crabs of the Atlantic coast of the eastern United States, Maine to Florida. Smithsonian Institute Press, Washington, DC. 550p. Woillez, M., Rivoirard, J., and Petitgas, P, 2009. Notes on survey-based spatial indicators for monitoring fish populations. Aq. Living Resources 22(2): 155-164. Woillez, M., Poulard, J., Rivoirard, J., Petitgas, P., and Bez, N., 2007. Indices for capturing spatial patterns and their evolution in time, with application to European Hake (Merluccius merluccius) in the Bay of Biscay. ICES J. Mar. Sci. 64(3): 537-550.

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In: Crabs: Anatomy, Habitat, Editors: K. Saruwatari, M. Nishimura

ISBN: 978-1-61942-225-4 © 2012 Nova Science Publishers, Inc.

Chapter 4

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NEUROSECRETORY STRUCTURE AND GONAD INHIBITING HORMONE IN EYESTALK AND THE PHYSIOLOGY AND BIOCHEMISTRY OF SPERMATOZOA IN ERIOCHEIR SINENSIS Xianjiang Kang, Shumei Mu, Yanqin Li, Lijun Cheng, Kui Ma,Genliang Li, Qi Wang, Guirong Liu and Gang Cao College of Life Sciences, Hebei University, China

ABSTRACT In this chapter, Eriocheir sinensis was studied on the characteristic of the eyestalk and spermatozoa. 5 types of the neuroendocrine cells in eyestalks of the crab were distinguished by optical microscope. They distributed on the medulla interns and medulla treminalia of the optic ganglia. In the sinus gland (SG), 5 types of neurosecretory terminals were identified via transmission electron microscope. By reverse-phase high-performance liquid chromatography (RP-HPLC), GIH were obtained. Measured by MOLDITOF-MS after further purification, its molecular weight is 6.8 ku. After immune localization of GIH in crab’s optic ganglia, we found GIH always located in type 1 and type 4 cells of optic ganglia.

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Xianjiang Kang, Shumei Mu, Yanqin Li, et al. Twelve different kinds of sperm membrane proteins from the mature spermatozoa of E. sinensis were analyzed by SDS-PAGE. Their molecular weights are between 21.6 ku and 75.5 ku, which indicate the sperm membrane proteins of E. sinensis are a set of proteins with low molecular weights. Gomori reaction and electron microscopy were used for localization of acid phosphatase during spermiogenesis in E. sinernsis. The results showed that: Acid phosphatase was synthesized in the endoplasmic reticulum in the early spermatids. The acid phosphatase was found gradually in nucleus, the membrane of acrosomal vesicle, the cytoplasmic region and the acrosomal tubule. And then the reaction product particles became thicker during the spermiogenesis. In the mature spermatozoa, acid phosphatase was localized in the percutor organ slightly, but it was massive and compact in the acrosomal tubule. With E. sinensis as the experimental material, this chapter is about extraction and antisera preparation of the compositions of spermic membrane proteins before acrosome reaction (SBAs) and spermic membrane proteins during third phase of acrosome reaction (SDAs) and PRAs, and those compositions are compared and analysed by sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE) to conjecture their effects on acrosome reaction of spermatozoa, as well as the effects of hydrophilic swelling, spermic density in buffer, trypsin, Ca2+, temperature, time of cryopreservation, compositions of cryopreservation buffers and three kinds of antisera mentioned above on acrosome reaction by the means of statistcs and microscope. We then built up three kinds of novel and simple methods inducing spermatozoa acrosome reaction (freezing method, trypsin-Ca2+ method and antisera method).

Keywords: Eriochier sinensis, Neuroseretory Structure, Gonad Inhibiting Hormone, Spermatophore, Spermatozoa, Sperm Membrane Proteins.

1. INTRODUCTION Chinese mitten-handed crab, Eriocheir sinensis, which belongs to Crustacea, Decapoda, Grapsidae, Eriocheir, is commonly known as river crab. Areas of origin are waters in temperate and tropical regions between Vladivostock (Russian Far East) and South-China, including Japan. Centre of occurence is the Yellow Sea (temperate regions of North-China). Along with the crab breeding industry flourishing in the coastal areas in China, the researches on its reproduction and development are also more and more

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Neurosecretory Structure and Gonad Inhibiting Hormone in Eyestalk… 73 extensive and in-depth. As we now know, like other crustaceans, all the events about the crab’s reproduction and development are related to the regulation of its neuroendocrine system. X organ-sinus gland system (XO-SG) is an important endocrine organ in the optic ganglia of the crustacean’s eyestalk, which could synthesize and excrete several kinds of neuropeptide, such as Crustacean hyperglycemic hormone (CHH), Molt-inhibiting hormone (MIH), Gonad-inhibiting hormone (GIH) and Mandibular organ-inhibiting hormone (MOIH). These neuropeptides have characteristics and primary structure attributes similar to CHH family all together. GIH is a neuropeptide of thermal stability and acdic isoelectric point, which can inhibit vitellogenesis in female, synthesis of gonad stimulate factor, activity of androgenic gland in male, synthesis of vitellin in hepatopancrea and methyl farnesol in mandibular organ. The neroupeptides’ synthesis and the content of GIH in optic ganglia of crustacean’s eyestalk are very low, so it is very difficult to separate and purify. For male E. sinensis, the detailed studies on the reproductive system (Du et al., 1988a; Wang et al., 2002; Wu et al., 2003), spermatogenesis (Du et al., 1988b; Wang et al., 1998), sperm structure (Du et al., 1987a), acrosome reaction (Du et al., 1987b; Du and Xue, 1987; Kang et al., 2009; Li et al., 2010a, 2010b) and fertilization (Du, 1998a, 1998b) have been reported. On sperm membrane surface, there are a variety of glycoproteins or glycocompounds, which have a close relationship with activities of fertilization, such as sperm-oocyte recognition, conglutination, binding and membrane fusion, so they play important roles in the course of fertilization (Cheng et al., 2003; Han et al., 2003; Ouyang et al., 2003; Sun et al., 2003; Wang et al., 2001; Zhou, 2003). In mammals, the sperm membrane proteins from human being, sheep, cattle, pig, rabbit, dog and mouse, have been focused on (Baker et al., 2002; Han et al., 1999; Liu et al.; Nancy, 2000, 2001; Sabeur et al., 2002; Wang et al., 2003; Wei et al., 1994; Zeng et al., 2000; Zhou et al., 1994,1995). Sperm membrane proteins that have been reported mostly belong to acid glycoprotein with low molecular weight, which is generally below 100ku (Nancy, 2000). Besides these mammals, Echinoidea and Haliotis are widely used as the experimental material now (Liu et al., 2003). However, there are rare researches on crustaceans at this content (Wang et al., 2010). In this chapter, sperm membrane proteins were extracted, divided, identified and studied its biochemical characteristics in E. sinensis. The aim is to help to prove up the mechanism of sperm-egg operation and fertilization, and provide basic information to study fertilization biology about crustacean.

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During the fertilization in most animals, living spermatozoa need to undergo an acrosome reaction. Similar to most crustaceans, the acrosome reaction of spermatozoa in E. sinensis consists of four steps (Du and Xue, 1987; Kang et al., 2009; Li et al., 2010a, 2010b): (a) the initiation of the reaction (the protrusion of the apical cap), (b) the reversion of the acrosomal vesicle, (c) the extension of the acrosomal tubule, and (d) shrinking and disappearance of the acrosomal vesicle and diminishing of nucleus. Because the acrosome reaction is a prerequisite for fertilization, it is often used to evaluate the spermatozoa motility in animals. The factors that influence the acrosome reaction also directly work on the process of the fertilization or in vitro spermatozoa storage (Du and Xue, 1987; Kang et al., 2009; Li et al., 2010a, 2010b; Lindsay and Clark, 1992; Wang, 1995; Bart et al., 2006; Magda et al., 2004; Nimrat et al., 2006; Thomas et al., 1988; Vuthiphandchai et al., 2007).

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2. NEUROENDOCRINE STRUCTURE OF EYESTALK AND GONAD INHIBITING HORMONE IN E. SINENSIS Eyestalks of the crab were found to have the same structures as that described by previous researchers. The optic ganglia in eyestalks, which are located under the ommateum is composed of three sections, medulla externa (ME), medulla interna (MI), and medulla terminalia (MT). The sinus gland (SG) is elliptical vesicle in shape, shown to be composed of axon terminals of the neuroendocrine cells and located at the side of MI and MT (Figure 1). According to cell form, size, neuclear diameter, cytoplasm and neuclear character in the optic ganglia of eyestlks in E. sinensis, five types of the neuroendocrine cells were found, and they all distributed on, MI and MT (Figure 2). The SG is composed primarily of axon terminals of the neurosecretory cells; it is elliptical vesicle in shape (Figure 1). The wall of the SG is composed of connective tissue and glial cells. The axon terminals are packed with numerous dense granules. Depending upon the size, morphology and electron density of granules, five types of axon terminals were identified (Table 1, Figure 3). In order to purify GIH from E. sinensis, crude hormone extracts of the optic ganglia was isolated by reverse-phase high-performance liquid

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Neurosecretory Structure and Gonad Inhibiting Hormone in Eyestalk… 75 chromatography (RP-HPLC) (Ma et al., 2007). Several single fractions whose elution peak came out in the range of the CHH family were obtained.

1. dissection diagram, bar= 0.5 mm; 2. microstructure diagram (longitudinal section), bar=100μm ME: medulla externa; MI: medulla interna; MT: medulla terminilia; 1 sinus gland. SG:

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Figure 1. Diagram of the optic ganglia of eyestalks in E. sinensis.

1 left surface; 2 right surface. ME: medulla externa, MI: medulla interna, MT: medulla terminalia, SG:sinus gland; E1: bottom of MT; E2: dorsal middle part of MT; E3: lateral of SG in MI; E4: fassa part of MT; ☆:cell type I; ▽:cell type II; □: cell type 3; ■:cell type 4;○:cell type 5. Figure 2. Diagrammatic sketch of the neuroendocrine cells distribution in the optic ganglia of eyestalk in E. sinensis.

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Xianjiang Kang, Shumei Mu, Yanqin Li, et al. Table 1. The types of axon terminals and the character of granules

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terminal types Ⅰ Ⅱ Ⅲ Ⅳ Ⅴ

granules size (nm) 170 (100-230) 157 (100-210) 115 (70-140) 90 (50-110) 64 (40-73)

granules electron density higher high higher higher low

granules shape cycloidal cycloidal cycloidal or elliptical cycloidal or elliptical cycloidal, elliptical or short virgulate

Figure 3. Neurosecretory granules types, bar=1 μm.

Through in vivo injection of the crabs, thebiological activity of each fraction was assayed; we found that fraction which was eluted in 38-40 mL had the greatest biological activity to inhibit the development of crabs’ oocytes. Measured by MOLDI-TOF-MS after further purification, its molecular weight was 6.8 ku. This protein whose elution peak came out in the range of the CHH family by RP-HPLC has similar properties as other Crustaceans’, such as small molecular weight, thermal stability and high biological activity of gonad inhibiting. So we consider that this protein is the GIH of E. sinensis. After immune localization of GIH in carbs’ optic ganglia, we found that GIH located always in type 1 and type 4 cells of optic ganglia. In the process of crabs breeding, many cultured larvae are precocious in scores. It will bring about smaller body and higher death rate, which constrict development of the breeding and bring numerous losses for production. The secretion unbalance and metabolism disorder of GIH is closely related to sex premature. GIH existed in both normal crabs and sex premature crabs, but the

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Neurosecretory Structure and Gonad Inhibiting Hormone in Eyestalk… 77 level of amount or the secretory of GIH in normal crabs was larger than sex premature crabs.

3. THE PHYSIOLOGICAL AND BIOCHEMICAL CHARACTERISTICS OF SPERMATOZOA AN E. SINENSIS

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3.1. Fractionation of Spermatophore Fractions and the Proteins Analysis in E. Sinensis The male reproductive system of E. sinensis was mainly composed of spermary, vas deferens, seminal vesicle and ejaculatory duct. The vas deferens could secrete seminal fluid; the seminal vesicle was the main storage for spermatophore as well as seminal fluid (Wang et al., 2000). Therefore, the seminal vesicle was used as the source of experiment materials in the experiment. In order to obtain free spermatozoa of E. sinensis, spermatophores stored in the seminal vesicle from mature male crab should be broken and centrifuged. The by-products harvested in this process, such as spermatophore matrix and seminal plasma, were also analyzed with SDS-polyacrylamide gel electrophoresis (SDS-PAGE) for the purpose of providing information to illuminate the mechanism of the sperm development and maturation and also to study the sperm-egg cooperation in crustacean. Mature male crabs (body weight 80-100 g) were dissected, the seminal vesicle could be got and cut into pieces and then put into the centrifuge at 10 000 g for 10 min. The supernatant was seminal fluid. Drawn the scattered spermatophores, rinsed them with the precooling buffer to obtain the pruified spermatophores, and broken the spermatophores to let the spermatozoa out. The supernatant was centrifuged at 10 g for spermatozoa and the spermatophore matrix. All samples were analyzed on SDS-PAGE (7.5% gel), and stained by Coomassie brilliant blue R-250 and periodic acid-Schiff's reagent for glycoprotein staining (Cheng et al., 2005). The spermatophore includes spermatophore matrix, seminal plasma and the whole sperm, had different characteristic bands in SDS-PAGE maps (Figure 4). The SDS-PAGE map of E. sinensis whole sperm implied many sorts of protein inside. Of these bands, about 16 bands could be identified; others were difficult to be distinguished due to relatively low protein content. The 16 bands could be divided into three areas Ⅰ, Ⅱ, Ⅲ from top to bottom

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(Figure 4: 2, 3): 7 bands with molecular weight above 97.4ku in areaⅠ; 3 bands with molecular weight between 66.2ku and 97.4ku in area II; 6 bands with molecular weight below 43 ku in area Ⅲ. Of 3 deeply stained bands in area III, the first was especially widely and deeply stained due to the largest protein contents while the proteins in area I, II had low contents. In SDS-PAGE map, spermatophore matrix had 3 main bands (Figure 4: 4, 5), 1 band with molecular weight above 97.4ku, and the other 2 about 43 ku. The two 43 ku proteins showed positively in glycoprotein staining. The 2 bands were easy to be viewed as one band due to their similarity in protein content and migration distance. It indicated that the major component of the spermatophore matrix was glycoprotein. So it could be deduced that the spermatophore wall may be nutritional to the sperm. The experiment results showed that the spermatophore matrix was mainly composed of glycoprotein, but the functions of these proteins remain to be further studied.

1. Marker; 2.3. Sperm (devided into three areasⅠ,Ⅱ, Ⅲ); 4.5. Spermatophore matrix; 6.7. Seminal plasma. Figure 4. SDS-PAGE maps of proteins from various parts of the spermatophore (7.5 %).

From the SDS-PAGE map of seminal plasma (Figure 4: 6, 7), it could be seen that there were 4 deeply stained bands. Among which, molecular of 2 bands was above 97.4 ku and that of 2 bands was about 31 ku. There were some lightly stained bands in the middle of the lane. By comparison with the SDS-PAGE map of seminal plasma with that of whole sperm, they had consistency in some bands. For example, the migration distances of the 2 bands about 31 ku were similar although the contents of them were different. During the sperm tours in the vas deferens, some proteins in seminal plasma

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Neurosecretory Structure and Gonad Inhibiting Hormone in Eyestalk… 79 may adhere to its surface, and then became the components of the sperm. The glycoprotein staining revealed the presence of three kinds of glycoprotein in seminal plasma. As the physiological environment for spermatophores and the scattered sperms, seminal fluid possibly had a certain nutrition function, but many proteins inside it, known as the glycoprotein, might be related to this function.

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3.2. Biochemical Characteristic of Sperm Membrane Proteins in E. Sinensis Improved Lowry method with TritonX-100, content of extracted sperm membrane proteins were determined (Zhang et al., 1999). Analysis of the sperm membrane proteins using 12% SDS-PAGE together with standard molecular weight protein marker, by origin protract standard curve of molecular weight, and calculate molecular weight of the sperm membrane proteins. The results showed it was also a set of acid glycoproteins with low molecular weight whose range is between 21.6-75.5 ku (Wang et al., 2010). The finding is fully closed to mammalians’ result above. Sperm membrane proteins in Decapoda are presumed that they may possess conservatism in composition of amino acids sequence as in mammalians, although both inevitably diversify in types and structure. Theoretically, sperm membrane protein should be a kind of protein with more conservative composition. In some way, the sperm membrane proteins act as important factors that participate in affecting the sperm and egg mutually have been understood. But fertilization molecular mechanism as well as each kind of membrane proteins in fertilization process function still remains the further research and exploration. Moreover, as for as the main research object – mammal is considered at present, although the structure and function of the heterogeneous’ sperm membrane protein has remarkable conservatism in the same category, during species in different category, molecular structure and function of the membrane proteins have large differences. Therefore, the differences about different inter-species membrane proteins still need for further studies.

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3.3. The Localization of Acid Phosphatase during Spermiogenesis in E. Sinensis Acid phosphatase (ACPase (EC.3.1.3.2)) is one of the most imporment enzymes, which catalyze hydrolyzing of phosphate mono-ester and producing phosphoric acid. Acid phosphatase has a close relation with phosphorus metabolism and substance metabolism. It is also a marker enzyme of lysosome in cell. During spermiogenesis, some important events occur, such as the change of organelles, the modifing and degradation of biomacromolecule. Acid phosphatase plays an important role in these events. So, the localization of acid phosphatase during spermiogenesis in E. sinernsis was investigated in this chapter. Gomori reaction and electron microscopy were used for localization of acid phosphatase during spermiogenesis in E. sinernsis. The samples (spermary, vas deferens and seminal visicle) were divided into two groups, experimental group and control group, respectively. In the experimental group, the samples were incubated in the incubation buffer containing R-Sodium Glycerophosphate served as substrate. On the contrary, the incubation buffer in the control group had no subtrate (Liu et al., 2006). During spermiogenesis, the spermatid underwent a series of changes until maturing. In the mature sperm, there was little cytoplasm in it. Organelles have also degenerated, and even disappeared. Only a thin cytoplasmic region was left between the nucleus and acrosome. The main part of mature sperm of E. sinensis was occupied by the nucleus and acrosome. The shape of nucleus was unique and named nuclear cup, located in the behind part of sperm. Acrosomal vesicle was situated in the nuclear cup. It consisted of apical cap, acrosomal tubules and acrosomal vesicle. Apical cap is the head part with high election density. Acrosomal tubule was formed by the prolongation of the invaginated retral membrane of the acrosomal vesicle. It was filled with thread-like material. The percutor organ is in the middle part of the acrosomal tubule, formed by high election density canaliculus. From inside to outside, the matter circling acrosomal tubules in the acrosomal vesicle was divided into three parts: fibrous layer, middle layer and lamellar structure (Figure 5). In the early stage of spermatid of E. sinensis, acid phosphatase was distributed on the membrane of irregular endoplasmic reticulum vesicle. Gomori reaction was negative in nucleus, indicating there was no acid phosphatase. Gomori reaction was negative in the control group. In the late stage of the spermatid, there was acid phosphatase in the nucleus, acrosomal tubules, the membrane of acrosomal vesicle and the cytoplasmic region. There

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were uniform and compact metal granules distributing in acrosomal tubules, membrane of acrosomal vesicle and cytoplasmic region, but there were less in the percutor organ of acrosomal tubules. There was no acid phosphase in the fibrous layer, middle layer, and lamellar structure of the acrosomal vesicles (Figure 6). There was no metal granule in the control group of different samples either.

AC. apical cap; AT. acrosomal tubules; FL. Fibrous layer; LS. lamellar structure; ML. middle layer; N. nucleus; NM. nuclear membrane; PM. plasma membrane; PO. percutor organ; RA. radial arm; bar=0.5 μm. Figure 5. The spermatozoa ultrastructure of E. sinensis.

AT. acrosomal tubules; CYR. cytoplasmic region; FL. Fibrous layer; N. nucleus, bar=0.5 μm. Figure 6. The location of acid phophatase of late spermatid during spermiogenesis of E. sinensis.

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CYR. cytoplasmic region; FL. Fibrous layer; LS. lamellar structure; N. nucleus; PO. percutor organ; bar=0.5μm.

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Figure 7. The location of acid phophatase of mature sperm in E. sinensis.

In the mature sperm, acid phosphatase was not observed in the nucleus and three parts of acrosomal vesicle, fibrous layer, middle layer and lamellar structure. The experiment result indicated that there were sporadic and thin metal granules in the percutor organ. In the acrosomal tubule, there were many large and dense metal granules. That is to say, there was acid phosphatase in the another part of acrosoml tubule (Figure 7). From the changes of acid phosphatase localization in spermatid, we thought that the acid phosphase proenzyme was synthesized in endoplasmic reticulum in the early spermatid stage, and transported from the cytoplasm to the nucleus, and then acid phosphase zymogens were actived by a specific signal. The regulating function of enzyme to gene is usually completed by phosphorylation and dephosphorylation. Acid phosphase in nucleus could regulate gene expression through activating or inhibiting some key enzyme, which related with gene expression.

3.4. Inducing Factors on Acrosome Reaction of Spermatozoa in E. Sinensis Acrosome reaction is an important process in fertilization. The factors that influence acrosome reaction also directly work on the prosess that

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Neurosecretory Structure and Gonad Inhibiting Hormone in Eyestalk… 83 spermatozoa and ovum complete fertilization successfully. Those spermic membrane proteins (SMPs) before and during acrosome reaction and the proteins released during acrosome reaction (PRAs) (including proteolysins) play important roles in the maintenance of spermic shape and structure, the metabolism of spermatozoa and the reproduction, especially in the fertilization such as recognization, combination and inosculation between spermatozoa and ovum. The spermatozoa of E. sinensis were extracted from spermatophere through the method of fractionation. And then the effects of hydrophilic swelling, spermic density in buffers, trypsin, Ca2+, temperature, time of cryopreservation, compositions of cryopreservation buffers were investigated on acrosome reaction of spermatozoa in E. sinensis. The results showed that spermatozoa demanded to experience process of hydrophilic swelling before acrosome reaction and hydrophilic swelling was possibly essential to acrosome reaction; high spermic density could evidently induce spermatozoa acrosome reaction to phase second, nevertheless low density of spermatozoa could not in Ca2+-FASW and to a certain extent could in ASW; trypsin cooperated with Ca2+, low temperature (-20 ℃, -80 ℃ and liquid nitrogen) and cryopreservation influenced acrosome reaction of spermatozoa so markedly that spermatozoa almost assumed acrosome reaction; Furthermore, low temperature and cryopreservation inducing acrosome reaction didn’t demand Ca2+; time of beginning and most acrosome reaction rate was incorrelate to temperatures and buffers but time of cryopreservation (Li et al., 2009). Acrosome reaction of spermatozoa was induced by freezing and compositions of PRAs and SMPs were isolated with centrifugal protein extraction after exposing to refreezing-thawing. Both proteolysins inside and outside of spermatozoa before and during the third phase of acrosome reaction. The results showed that there were 12 kinds of active proteolysins inside and outside of spermatozoa before and during acrosome reaction. And then maps of SDS-PAGE and native polyacrylamide gel electrophoresis (Native-PAGE) of various spermic proteins samples were compared and analysed. The results showed that there were changes of SMPs before and during acrosome reaction and some SMPs were released during phase third of acrosome reaction. Utilizing SBAs, SBAs and PRAs extracted, male mice were immunized to produce three kinds of antisera. We also detected male tissue specificity of SMPs and PRAs, which results indicated that three kinds of antisera had obvious immunoprecipitation with crude extracts of testis, vas deferens and seminal vesicle but male serum.

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Furthermore, we coincubated the three kinds of antisera and serum in control group to analyse their effects on acrosome reaction, which results implied that the antisera of SBAs could effectively induce spermatozoa acrosome reaction in sequence to four phases, and profiles of spermatozoa could be clearly observed by the means of microscope. Therefore, the method of antisera inducing acrosome reaction was either novel method of effectively inducing acrosome reaction and available way of observing the shapes of spermatozoa. In conclusion, E. sinensis’ spermatozoa have the process of hydrophilic swelling, and pressing and low temperature (or difference in temperature) are important inducement of acrosome reaction, and Ca2+ has an activation to the trypsin that induces acrosome reaction outside the spermatozoa; spermatozoa obtained by the method of triturating or trypsin-digested under low density (5×106 spermatozoa/mL) in Ca2+-FASW had high quality and acrosome reaction hardly occur, freezing method, trypsin-Ca2+ method and antisera method can induce acrosome reaction efficiently; There are several experiment proofs demonstrated the spermatozoa possess of capacitation.

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CONCLUSION As noted above, 5 types of the neuroendocrine cells in eyestalks of E. sinensis were distinguished; and 5 types of neurosecretory terminals were identified in SG. GIH, which is always located in type 1 and type 4 cells of optic ganglia, were obtained by RP-HPLC; its molecular weight is 6.8 ku. The sperm membrane proteins of E. sinensis are a set of proteins with low molecular weights, from 21.6 ku to 75.5 ku. In the early spermatids, acid phosphatase was synthesized in the endoplasmic reticulum, and located in the nucleus, the membrane of acrosomal vesicle, the cytoplasmic region and the acrosomal tubule. In the mature spermatozoa, acid phosphatase was localized in the percutor organ slightly, but it was massive and compact in the acrosomal tubule. The spermatozoa demanded to experience the process of hydrophilic swelling before acrosome reaction and hydrophilic swelling was possibly essential to acrosome reaction; high spermic density could evidently induce spermatozoa acrosome reaction to phase second, nevertheless low density of spermatozoa could not in Ca2+-FASW and to a certain extent could in ASW; trypsin cooperated with Ca2+, low temperature (-20 ℃, -80 ℃ and liquid nitrogen) and cryopreservation induced acrosome reaction of spermatozoa;

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Neurosecretory Structure and Gonad Inhibiting Hormone in Eyestalk… 85 Furthermore, low temperature and cryopreservation inducing acrosome reaction didn’t demand Ca2+. The antisera of SBAs could effectively induce spermatozoa acrosome reaction in sequence to four phases. Therefore, the method of antisera inducing acrosome reaction was either novel method of effectively inducing acrosome reaction and available way of observing the shapes of spermatozoa. In conclusion, the present study may be beneficial to new understandings of reproductive endocrine controlling, mechanism of acrosome, and provide the foundational material for artificial fertilization and breeding of this crab and other commercial aquatic crustaceans.

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REFERENCES Baker SS, Cardullo RA, Thaler CD. Sonication of Mouse Sperm Membranes Reveals Distinct Protein Domains. Biology of Reproduction., 2002; 66: 57-64. Bart AN, Choosuk S, Thakur DP. Spermatophore cryopreservation and artificial insemination of black tiger shrimp, Penaeus monodon (Fabricius). Aquaculture Research, 2006; 37(8): 523-528. Cheng LJ, Kang XJ, Zhao XY. [The research progress of sperm membrane surface protein.] Chinese Journal of Zoology,2003; 38(6):125-128. Chinese. Cheng LJ, Kang XJ, Mu SM, Guo MS, Zhao XY. [The Fractionation of spermatophore and analysis of proteins in various fractions in Eriocheir sinensis.] Chinese Journal of Zoology, 2005; 40(5): 95-98. Chinese. Du NS. [The fertilization biology of chinese mitten-handed crab, Eriocheir sinensis (Crustacea, Decapoda) (1).] Biology bulletin,1998a; 33(12):5-8. Chinese. Du NS. [The fertilization biology of chinese mitten-handed crab, Eriocheir sinensis (Crustacea, Decapoda) (2).]. Biology bulletin, 1998b; 34(1):1012. Chinese. Du NS, Xue LZ, Lai W. [Histology of the Male Reproductive System in Eriocheir sinensis (Decapoda,Crustacea).]. Aeta Zoologica Sinica, 1988a; 34(4):329-333. Chinese. Du NS, Xue LZ, Lai W. [Studies on the Sperm of Chinese Mitten-handed Crab, Eriocheir sinensis (Crustacea, Decapoda) II. Spermatogenesis.] Oceanologia et Limnologia Sinica,1988b; 19(1):71-75.Chinese.

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Copyright © 2012. Nova Science Publishers, Incorporated. All rights reserved.

86

Xianjiang Kang, Shumei Mu, Yanqin Li, et al.

Du NS, Lai W, Xue LZ. [Studies on the Sperm of Chinese Mitten-handed Crab, Eriocheir sinensis (Crustacea, Decapoda) I. The Morphology and Ultrastructure of Mature Sperm.] Oceanologia et Limnologia Sinica, 1987a; 18(2):119-124.Chinese. Du NS, Lai W, Xue LZ. [Acrosome reaction of the sperm in the Chinese mitten-handed crab, Eriocheir sinensis (Crustacea, Decapoda).] Acta zoological sinica, 1987b; 33(1):8-13. Chinese. Du NS, Xue LZ. Induction of acrosome reaction of spermatozoa in the decapoda Eriocheir sinensis. Chinese Journal of Oceanology Limnology, 1987; 5 (2): 118-123. Han XL, Zheng RL. [The research progress of structure and ligand related to sperm membrane capacitation and acrosome reaction in mammal.] Foreign Medical Sciences (Urinary System), 2003; Suppl 1: 39-41 .Chinese. Han ZM, Zhuang DZ, Gao SR, Song XF, Chen DY. [Glycoprotein changes in mouse sperm plasma membrane during epididymal maturation.] Acta Zoologica Sinica,1999; 45(1):93-98. Chinese. Kang XJ, Li GL, Mu SM, Guo MS, GE SQ. Acrosome reaction of Chinese mitten-handed crab Eriocheir sinensis (Crustacea: Decapoda) spermatozoa: promoted by long-term cryopreservation. Aquaculture, 2009; 295:195-199. Li GL, Kang XJ, Li YQ, Mu SM, Guo MS. Acrosome reaction of spermatozoa in the Chinese mitten crab, Eriocheir sinensis (Decapoda, Grapsidae): induced by anti-spermatozoal membrane proteins antiserum. Crustaceana, 2010a; 83(8): 915-926. Li GL, Kang XJ, Mu SM. Induction of acrosome reaction of spermatozoa in Eriocheir sinensis by low temperature. Cytotechnology, 2010b; 62:101107. Lindsay LL, Clark WH Jr. Preloading of micromolar intracellular Ca2+ during capacitation of Sicyonia ingentis sperm, and the role of the pHi decrease during the acrosome reaction. Journal of Experimental Zoology, 1992; 262(2): 219-229. Liu HH, Li TW, Su XR, Huang B. [The research progress of abalone’s gamete recognition protein.] Chinese Journal of Zoology, 2003; 38(6):104109.Chinese. Liu GR, Kang XJ, Guo MS, Sun WJ, Wang Q. [The study on the localization of acid phosphatase during spermiogenesis in Chinese Mitten-Handed Crab, Eriocheir sinensis.] Journal of Oceanography in Taiwan Strait, 2006; 25(1): 25-29. Chinese.

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Neurosecretory Structure and Gonad Inhibiting Hormone in Eyestalk… 87 Liu JX, Lin AX, Yang Y, Chen YF. [High Expression of rabbit sperm membrane protein rsp10 in Escherichia coli and preparation of its specific antisera.] Chinese Journal of Biotechnology, 2001; 17(3): 314-317. Chinese. Ma K, Kang XJ, Mu SM, Zhang L, Wen XR. [Primary study of GIH isolation in Eriocheir sinensis by RP-HPLP.] Journal of Fishery Sciences of China, 2007; 14(2): 331-335. Chinese. Magda L, Clarissa G, Marcela S. The use of flow cytometry in the evaluation of cell viability of cryopreserved sperm of the marine shrimp (Litopenaeus vannamei). Cryobiology, 2004; 48: 349-356. Nimrat S, Siriboonlamom S, Zhang S, Xu Y, Vuthiphandchai V. Chilled storage of white shrimp (Litopenaeus vannamei) spermatophores. Aquaculture, 2006; 261: 944-951. Nancy P. Systematic Characterization of Sperm-Specific Membrane Proteins in Swine. Biology of reproduction, 2000; 63:1839-1847. Ouyang, XH, Xi GS. [Distribution and changes of agglutinin receptors during animal spermtogensis and maturation.] Journal of Shanxi Normal University (Natural Science Edition), 2003; .31(Suppl 1): 226229.Chinese. Sabeur K, Foristall K, Ball BA. Characterization of PH-20 in canine spermatozoa and testis. Theriogenology,2002; 57(2): 977-987. Sun YH, Diao HL, Zhao CL, Li XY, Wang GL. [On the acrosomal membrance proteins of sperm.] Journal of Binzhou Medical College, 2003; 26(5): 326-328.Chinese. Thomas A, Crowe JH, Griffin FJ, Clark WH Jr. Cryopreservation of sperm from the marine shrimp Sicyonia ingentis. Cryobiology, 1988; 25: 238243. Vuthiphandchai V, Nimrat S, Kotcharat S, Bart AN. Development of a cryopreservation protocol for long-term storage of black tiger shrimp (Penaeus monodon) spermatophores. Theriogenology, 2007; 68: 11921199. Wang YL, Zhang ZP, Li SJ. [The Reviews of Studies on the Spermatology of Crustatea II. Spermatogenesis and the Biochemistry of Sperm.] Chinese Journal of Zoology, 1998; 33(4):52-57.Chinese. Wang GL, Cui CD, Xia ZK, Diao HL, Zhi XL. [The study on purification and characterization of human sperm acrosome membrane protein.] Chinese Journal of Applied Physiology, 2003; 19(4): 376-377.Chinese.

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88

Xianjiang Kang, Shumei Mu, Yanqin Li, et al.

Wang HF, Wang YX. [The research progress of sperm membrane antigen.] Foreign Medical Sciences(Urinary System), 2001; 21(3): 126128.Chinese. Wang Q, Kang XJ, Cheng LJ, Mu SM, Cao G. [Biochemical characteristic of sperm membrane proteins in Eriocheir sinensis.] Journal of Fishery Sciences of China, 2010; 17(1): 156-160. Chinese. Wang Q, Zhao YL, Lai W, Du NS. [Ultrastructural Study on Spermatophore Formation in Eriocheir sinensis H. Milne Edwards.] Journal of East China Normal University, 2000; (3):98-103.Chinese. Wang Q, Zhao YL, Chen LQ. [Biochemical Composition and Sperm Metabolism in the Reproductive System of the Male, Eriocheir sinensis.] Journal of Fisheris of China, 2002; 26(5):411-416. Chinese. Wang QY, Misamore M, Jiang CQ, Browdy CL. Egg water induced reaction and biostain assay of sperm from marine shrimp Penaeus vannamei: dietary effects on sperm quality. Journal of the World Aquaculture Society, 1995; 26(3): 261-271. Wei SG, Wang LF, Miao SY, Shi XQ, Zong SD. [Purification of a human sperm protein(BS-17) related to fertilization.] Chinese Journal of Biochemistry and Molecular Biology,1994; 10(2):236-241. Chinese. Wu P, Lou YD, Qiu GF. [Morphological, Histological and Histochemical Variation of Sexual Gland Development in Eriocheir sinensis.] Journal of Shanghai Fisheries University, 2003;12(2):106-112.Chinese. Zeng SJ, Sang JL, Liang QJ. [The purification and effects on reproduction of bull sperm-surface glycoprotein having affinity for con A.] Journal of Beijing Normal University (Natural Science). 2000; 36(5): 683-687. Chinese. Zhou F. [The research progress of membrane changes in sperm maturation.] Foreign Medical Sciences(Family Planning Fascicle), 2003; 22(3): 171174. Chinese. Zhou ZX, Deng ZP. [Characterization marked by sheep sperm-surface agglutinin.] Chinese Journal of Histochemistry and Cytochemistry, 1994; 3(3): 256-269. Chinese. Zhou ZX, Deng ZP, Sun XH. [Antigenic property and biological role of concanavalin a-binding glycoprotein of sperm plasma membrane.] Acta Anatomica Sinica, 1995; 26(2):170-175.Chinese. Zhang XM, Shi YS. [Protein quantitation of Lowry having TritonX-100.] Journal of First Military Medical University,1999; 19(1): 73.Chinese.

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In: Crabs: Anatomy, Habitat, Editors: K. Saruwatari, M. Nishimura

ISBN: 978-1-61942-225-4 © 2012 Nova Science Publishers, Inc.

Chapter 5

BEHAVIORAL DIFFERENCES IN FIDDLER CRABS, UCA PUGNAX, FROM CONTAMINATED AND REFERENCE ESTUARIES IN NEW JERSEY Lauren L. Bergey,1,2, Terry Glover3 and Judith S. Weis1 1 Copyright © 2012. Nova Science Publishers, Incorporated. All rights reserved.

Rutgers, The State University of New Jersey, Department of Biological Sciences, Newark, NJ, US 2 Centenary College, Department of Mathematics and Natural Science, Hackettstown, NJ, US 3 Bloomfield College, Division of Social and Behavioral Sciences, Bloomfield NJ, US

ABSTRACT Studies on a variety of organisms have shown reduced activity levels and reduced prey capture or feeding in polluted environments compared to animals from cleaner sites. Laboratory and field studies were performed on fiddler crabs (Uca pugnax) from a polluted vs. reference environment in New Jersey. Based on prior studies, we hypothesized that crabs from the contaminated site would eat less and would be less active than those from the reference site, and that this would have deleterious effects. Overall, the crabs from the contaminated site, Piles Creek (PC), 

Corresponding author [email protected]

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Lauren L. Bergey, Terry Glover and Judith S. Weis tended to spend more time inactive on the surface or in their burrows compared with crabs from Tuckerton (TK), the reference site. TK crabs generally spent more time active and feeding. While reduced feeding suggests that growth might be reduced in the PC crabs, a previous study found that they tend to be larger, not smaller at PC, but have lower density. Differences in levels of available nutrients may play a role in behavioral differences. Also, spending more time inactive in their burrows would reduce energy expenditures and could also make them less likely to be captured by a predator. In an experiment in which crabs from both populations were exposed to a blue crab (Callinectes sapidus) predator, PC crabs were less likely to be captured, which may be related to their greater tendency to stay in burrows. Thus, despite having reduced activity levels and reduced feeding, crabs at PC did not appear to suffer adverse ecological consequences.

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INTRODUCTION Many studies have indicated that contaminants can cause behavioral changes in invertebrates (Boyd et al., 2002). Wallace et al. (2000) demonstrated that the grass shrimp, Palaemonetes pugio, had reduced prey capture of its brine shrimp prey, Artemia salina, when it was fed a Cdcontaminated diet. Khoury (1995) found that Uca pugnax from contaminated sites had reduced foraging behavior compared to crabs from a cleaner site. Behavioral impairment in other crab species due to contaminants has been studied (Hui, 2002). However, while many studies have linked individual cellular, physiological, reproductive and behavioral changes to contamination, fewer studies have related behavioral impairments to population and community-level changes (Weis et al., 2001). Smith and Weis (1997) found that killifish (mummichogs) (Fundulus heteroclitus) from Piles Creek (PC), a heavily polluted site, had reduced prey capture of grass shrimp, Palaemontes pugio, compared to same fish species from Tuckerton (TK), a relatively clean site. PC mummichogs made significantly fewer attempts to capture prey. In other experiments, they were found to be more likely to be captured by blue crabs, Callinectes sapidus. Due to the reduced prey capture by the fish, the grass shrimp population at PC is thriving: shrimp are large and are found in high densities (Santiago Bass et al., 2001). Reichmuth et al. (2009) found that adult blue crabs from a contaminated site, the Hackensack Meadowlands of New Jersey, were less effective than conspecifics from TK in capturing active prey including juvenile blue crabs and mummichogs. A shift in predator-prey relationships can cause major changes in the abundance, behavior, habitat

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utilization, distribution, physiology, and morphology of prey and predators (Werner et al., 1983; Posey and Hines, 1991). This might be termed “food web disruption.” Fiddler crabs live in socially complex communities and have a large repertoire of behaviors. They excavate extensive burrows, typically a few inches deep, throughout intertidal mudflats and salt marsh surface (Crane, 1975). They excavate with the minor chela in males and either chela in females; this involves moving sediment, with the chela and walking legs, in well-compacted balls, out and away from the burrow (Crane, 1975). Burrows serve as a refuge from predators, as well as a place to moisten gills during low tide, molt, mate, incubate eggs, and overwinter (Crane, 1975; Powers and Cole, 1976; Ringold, 1979; Christy, 1982). Some toxicants alter burrowing behavior (Weis and Perlmutter, 1987). Fiddler crabs feed on detritus and algae associated with sediment particles, so prey capture ability is not relevant to them. The amount of feeding, however, could be altered by pollutants, as could their activity level. They pick up sediment with their feeding claws, process it with their mouthparts, extract nutrients, and redeposit it as small pellets (Reinsel, 2004). Nutrients are obtained mainly from microscopic algae, bacteria, and protists in the detritus. Fiddlers benefit from organic matter on the sediment surface under enriched conditions (Skov and Hartnoll, 2002). In enriched environments, they may spend less time feeding and more time in other activities (Reinsel 2004). Uca spp. use vision to detect predators (Land and Layne, 1995). Their primary defense is to escape into the closest burrow (Crane, 1975). If they are near the water’s edge and burrows are too far away, they burrow into soft sediment or run into the water until they are fully submerged (Crane, 1975). Walking and running are always done sideways. They can run rapidly for short distances when needed (Crane, 1975), usually when they feel threatened. A running crab can trigger nearby crabs to run to their burrows. They have complicated courtship behavior in which the male waves his enlarged claw to attract females. Males with larger claws are more likely to attract females (Hyatt, 1977). Both the major and minor cheliped are raised simultaneously and moved in a species-specific pattern. Uca pugnax’s pattern is obliquely-out-and-up then in-and-down (Crane, 1975). Some species of fiddler crabs mate on the marsh surface, while others, including U. pugnax, mate in burrows. Display and aggressive behavior involve a male moving its major cheliped out from the body and holding it in front of a potential aggressor as a warning (Wolfrath, 1993). Physical contact in which one crab moves another

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is considered aggression, and usually occurs when a wandering male approaches a burrow that is already inhabited by another male. The inhabitant usually emerges and fights with the intruder (Crane, 1975; Wolfrath, 1993). Fights involve pushing each other back and forth; occasionally the chelipeds will lock and one crab may flip the other one over (Wolfrath, 1993). Females also engage in aggression over burrows and push back and forth until one surrenders the burrow. Behavioral impairment has been seen in other aquatic organisms from polluted sites (Boyd, 2002; Hui, 2002; Smith and Weis, 1997). Behavioral impairments in fiddler crabs due to pollutants have been previously demonstrated: sluggishness and premature egg dropping (Vernberg and Vernberg, 1974), reduced foraging (Khoury, 1995), reduced burrowing (Weis and Perlmutter, 1987), and reduced escape response (Krebs et al. 1974). The following studies were performed to investigate behavior and activity in populations from differentially polluted sites.

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Study Sites Both sites have strong tidal flushing and are dominated by Spartina alterniflora. Fiddler crab burrows are located on the open mud flat and into the Spartina. The two sites differ substantially in contaminant levels.

Piles Creek (PC) Piles Creek (PC) in Linden, New Jersey, is a tributary of the Arthur Kill, a channel separating Staten Island from New Jersey and connecting Newark Bay in the north to Raritan Bay in the south. Industrial sites, a sewage treatment plant, and a major highway surround the site. Oil spills in the Arthur Kill have also been a source of organic contaminants. This site has been the source of ecotoxicological research for over 20 years. Elevated levels of organic contaminants and metals occur in sediments and biota (Weis et al., 2001). For example, metals in µg g-1 average: Hg 6.3, Pb 107, Cd 7.1, Cu 485. Salinity at PC ranges from 9 to 21 with an average of 15 ppt (Santiago, 1997).

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Great Bay-Mullica River Estuary (TK) The Tuckerton (TK) site is part of the Great Bay-Mullica River Estuary and part of the Jacques Cousteau National Estuarine Research Reserve in New Jersey. It is part of 3,500 acres of protected salt marsh. It is not industrialized, much less contaminated, and has also been monitored and used as a reference site during many years of research. Average sediment metals in µg g-1 (Weis et al. 2001) are Hg 0.19, Pb 73.2, Cu 141, and Cd 2.1 (Weis et al., 2001). Salinity at TK ranges from 22 to 29 (Miller et al., 2002).

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Collection and Maintenance Uca pugnax males and sediments were collected from May to September 2002-2006 from both locations during low to mid-tides from the intertidal zones including the marsh surface. Crabs were removed from burrows by placing a trowel into the sediment just below the burrow and lifting upward. This blocked the escape route into the deeper part of the burrow, and the fiddlers would then emerge. Crabs were measured for carapace width and claw size and then, to distinguish between the populations in lab studies, marked with liquid Whiteout®. Holding tanks were set up with native sediments in 75.7 liter aquaria. Half of the aquarium had sediment 15 cm deep and the other half was filled with 18 ppt artificial sea water 10 cm deep. The two portions of the tank were separated by a vertical glass plate as high as the sediment, held in place with small glass jars. The plate allowed the crabs to burrow in the sediment without it collapsing. Water was changed every other day, and sediment was changed weekly. Purina “Fly Chow” and Tetramin® flakes were sprinkled on top of the sediment every other day for food. The light cycle was 12/12 and the ambient room temperature was 23-24 C.

Activity Budgets in the Lab To determine if there were differences in how male fiddlers from two populations spend their time, activity budgets were constructed. Trials were set up in a room without disturbance and videotaped. After pilot studies showed that individual males did not behave the same way as when there was more than one crab, two males from each location were used for each observation, and crabs from one population (alternately PC or TK) were marked. Twenty

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trials were conducted using a total of 40 crabs from each population in a round container (78.7 cm height, 59.7 cm top diameter and a 54.6 cm bottom diameter) with sediments on the bottom. Using five-minute intervals on the video tapes, the percentage of time spent in each of the following eight activities was noted: walking, resting (standing), aggression, displaying, in burrow, emerging from burrow, feeding, and grooming. The total proportion of time spent on each activity was calculated for each group. A one-way ANOVA was performed.

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Activity Budgets in the Field A similar activity budget study was conducted in the field in 2003 and 2005. Observations were made during low tide when the maximum activity levels occur. Observers sat in camping chairs and allowed ten minutes from initial set up before recording behaviors in order to allow crabs to resume normal activity after the initial disturbance. Individual crabs were chosen at random and all their behaviors were recorded and analyzed from videotapes at five-minute intervals. A total of 12 TK and 6 PC crabs were analyzed in 2003 and 20 TK and 12 PC crabs in 2006. One way ANOVAs followed by Tukey all-pairwise comparison tests were performed for each of the behaviors (feeding, display, grooming, time in burrow, emerging from burrow, stationary, aggression, running, walking, and waving) to determine if there were site differences.

Feeding Rate in the Field Feeding rates (number of scoops/30 sec) were measured for 20 crabs from TK and 20 crabs from PC by recording the number of times the feeding claw went from the sediment surface to the mouth. Observations at each site were conducted within one day of each other during warm, sunny days. Data were analyzed with a two sample t-test.

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Surface Activity Twenty-five crabs from each population were placed in holding tanks with native sediments (described previously), TK crabs on TK sediment, PC crabs on PC sediment. The two tanks were side by side in the laboratory with the same light cycle and temperatures, and crabs were released into them at the exact same time. Crabs were left undisturbed for 48 hours to allow time for them to build burrows, then the crabs on the surface of each tank were counted every 30 minutes for a total of 8 hours. A two-sample t-test was performed on these data.

C and N Analysis

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Carbon and nitrogen analysis was performed on three surface sediment samples from PC and TK using the Carlo Erba NA-1500 analyzer that utilizes flash combustion, as per Verardo et al. (1990). A one-way ANOVA was performed on these data.

Predator-prey Experiment To determine if behavior might affect vulnerability to a predator, an experiment was set up in round containers with a height of 43 cm, a bottom diameter of 46.5 cm and a top diameter of 51 cm, containing either TK sediment or PC sediment at a depth of 30 cm. Twenty marked crabs were put into each container, 10 from PC and 10 from TK. After allowing the crabs to burrow for 24 hours, a simulated high tide was created by adding 18 ppt salt water until the water was 10 cm over the top of the sediment. After two hours acclimation, the predator, one blue crab (C. sapidus), which had been unfed for 48 hours, was introduced. Half of the blue crabs were from TK, the others from the Hackensack Meadowlands (another contaminated estuary connected to Newark Bay.) After 24 hours the blue crab was removed, the water drained, and the number of survivors from each population recorded. Six trials were conducted (three on each sediment type). A Chi-square was conducted on these data.

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RESULTS Activity Budget in Lab Crabs spent the most time walking, resting (standing), and in the burrow. Feeding was a relatively small part of the activity budget. PC crabs spent significantly more time displaying than TK crabs (F = 5.62, p = 0.021) (Figure 1). TK crabs spent more time grooming than PC crabs (F = 3.75, p = 0.057) (nearly significant). Although it appears that PC spent more time in burrows and TK spent more time walking, there were no significant differences found in walking (F = 0.75, p = 0.385), time spent in burrows (F = 1.73, p = 0.193), feeding (F = 1.41, p = 0.239), aggression (F = 0.08, p = 0.239), emerging from the burrow (F = 1.87, p = 0.176), or resting (F = 1.53, p = 0.220).

100%

% of Total Time

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90% 80%

Feeding

70%

Grooming

60%

In Burrow Resting

50%

Display

40%

Aggression

30%

Walking

20%

Other Behaviors

10% 0% TK

PC

Figure 1. Activity budgets for TK and PC crabs from laboratory experiments. “Other behaviors” included any behavior that was 2% or less of the total time (emerging from burrow).

Activity Budget in Field While resting (standing) and being in the burrow remained important as in the laboratory crabs, crabs in the field spent much of their time feeding. In

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2003, TK crabs spent more time feeding than PC (almost significant - F = 3.97, p = 0.061). PC crabs spent significantly more time resting (F = 11.9, p = 0.003) and waving (F = 6.53, p = 0.019) than TK crabs (Figure 2). There were no significant differences in aggression (F = 1.18, p = 0.292), emerging from the burrow (F = 0.67, p = 0.425), walking (F = 0.01, p = 0.930), or time spent in the burrow (F = 0.15, p = 0.705). In 2005, TK crabs again spent more time feeding (almost significant, F = 2.99, p = 0.062) while PC crabs again spent more time resting (F = 3.27, p = 0.048). There were no significant differences in aggression (F = 0.27, p = 0.764), time spent in the burrow (F = 0.45, p = 0.640), display (F = 0.69, p = 0.508), emerging from the burrow (F = 0.96, p = 0.392) grooming (F = 1.49, p = 0.238), walking (F = 0.94, p = 0.398), or posing (F = 0.97, p = 0.389) (Figure 3).

Feeding Rate in Field

100% 90%

% of Total Time

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There were no significant differences in feeding rates. PC crabs averaged 22.73 + 0.91 (SE) scoops/ 30 sec. and TK averaged 24.00 + 0.97 scoops/30 sec (t = 0.96, p = 0.340).

80%

Feeding

70%

Emerging

60%

In Burrow Resting

50%

Aggression

40%

Walking

30%

Waving

20%

Other Behaviors

10% 0% TK

PC

Figure 2. Activity budgets for TK and PC crabs from field observations in 2003. “Other behaviors” included any behavior that was 2% or less of the total time (running).

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100% 90% 80% Feeding

70% % of Total Time

Posing 60%

In Burrow

50%

Resting

40%

Walking Waving

30%

Other Behaviors

20% 10% 0% TK

PC

Surface Activity: The average number of TK crabs on the sediment surface in the lab was significantly more than PC (15.00 + 0.44 vs. 12.25 + 0.44) (t = 4.42, p < 0.001).

Carbon and Nitrogen Analysis 4.00 Percent (%)

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Figure 3. Activity budgets for TK and PC crabs from field observations in 2005. “Other behaviors” included any behavior that was 2% or less of the total time (aggression, display, emerging from burrow, and grooming).

*

3.00

Nitrogen

2.00

Carbon

1.00 0.00 Tuckerton

Piles Creek

Figure 4. Carbon and nitrogen analysis from surface sediment samples from TK and PC. Asterisk indicates significant difference. All SE were below 0.1 percent.

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60

Number of Crabs

50 40 Survivors 30

Consumed

20 10 0 TK

PC

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Figure 5. Number of TK and PC survivors and those consumed by the blue crab in the predator-prey experiment. Six trials were completed with ten fiddler crabs from each population.

C and N Analysis: There was no significant difference (F = 4.86, p = 0.092) in the percent N of sediment samples taken from the two locations. However, PC sediments contained significantly higher C (F = 28.4, p = 0.006) than TK sediments (Figure 4). Predator-Prey: Significantly more TK crabs were consumed by the blue 2 crab, Callinectes sapidus (1, N = 60) = 5.55, p = 0.019 (Figure 5).

DISCUSSION Differences in feeding were not seen in the laboratory, but in the field, TK crabs generally spent more time feeding than PC crabs, while PC generally spent more time resting (standing). In 2003, TK crabs spent about twice as much time feeding (59.9% of total time) than PC crabs (29.3% of total time). In 2005 TK crabs again spent more time feeding (63%) compared to PC crabs (36%) (not quite statistically significant to the 0.05 level) and PC crabs spent more time resting (PC 23%; TK (6%). Crabs in the field spent more time feeding than those in the laboratory, probably because lab crabs were provided

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with other food. Reduced activity and feeding by PC crabs supports our hypothesis. There was no difference seen in the lab in burrowing behavior and no statistically significant difference found in time spent in burrows in the field. However, field observations are biased against crabs that are in their burrows at the beginning of the observation period. In the lab experiment, significantly more TK crabs were out on the surface and more PC crabs were in burrows. C and N analysis showed that PC sediments had significantly higher C than TK sediments, but there was no significant difference in the amount of N. It appears that PC sediments are enriched in C, which might allow PC crabs, which spend less time feeding, to obtain enough nutrition. Particle size at PC was smaller (98% particles < 63 µm vs 43% particles < 63 µm at TK) (Taghon and Gruber, personal communication), and smaller particles have smaller interstitial spaces, which causes water to drain more slowly and are likely to retain more nutrients. Reinsel and Rittschof (1995) determined that sediment organic content and water content were the most important factors in determining where Uca pugilator foraged. Weis and Weis (2004) studied different species of Indonesian fiddler crabs and found that those that foraged on the richer food source spent less time feeding; U. vocans, living in sediment with coarse sand particles with low C and N, fed the fastest and spent the most time feeding. Caravello and Cameron (1991) found that the amount of organic material in sediments did not correlate with foraging time in U. panacea and suggested that predation pressure and thermal stress appear to be the strongest factors affecting foraging behaviors. However, personal observations suggest that there are more avian predators at TK than PC, so one would expect TK crabs to spend less time foraging if predation pressure was a factor. It is also important to note that TK has a higher population density than PC (Bergey and Weis, 2008), which could increase competition for food, and which may require TK crabs to feed more. That study found that PC crabs were, in general, larger than TK crabs, implying that reduced feeding is not impairing their growth. On the other hand, it is possible that the higher C and C:N ratio of PC sediments provides a less nutritious diet. According to principles of ecological stoichiometry, the relatively lower proportion of N indicates a lower nutrient value to detritivores, and the increased C would be in excess and would not be utilized for growth (Anderson et al 2004; Hessen 2004; Frost et al. 2005). A lower C:N ratio (as at TK) implies increased bacterial populations and increased N availability. Increased bacteria would benefit Uca, as this is an important component of their diets (Meziane et al., 2002). Increased N

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availability is also beneficial since detrivores are thought to be N limited. So, even though there is less C at TK, there could be more available N, which would be a better diet since fiddler crabs there are likely N limited. Reduced feeding was seen in mummichogs (Fundulus heteroclitus) from PC (Smith and Weis 1997). Like the crabs, those fish were less active and fed less. The fish, however, had reduced growth and lifespan, and there is no evidence for this in the PC crabs, which are larger than TK crabs (Bergey and Weis 2008). In the predator-prey experiment significantly more (about twice as many) TK crabs were consumed than PC crabs. While it was not possible to videotape this study to see what was actually happening, differences in survival could be related to the tendency of TK crabs to spend more time on the surface feeding and PC to spend more time in burrows. Many studies have demonstrated a relation between increased foraging times and increased predation risk (Milinski and Heller, 1978; Dill, 1987; Sih, 1994; Lima, 1998). Whether the TK crabs went up to the surface during the “high tide” is unknown. There do not appear to be any obviously aberrant behaviors in the PC crabs resulting from living in a highly contaminated site. Their reduced activity and decreased foraging may be beneficial to them. Spending more time inactive or in burrows can reduce energy expenditure and allow them to put more energy into growth. Increased time in burrows can also reduce predation by blue crabs and avian predators, both of which cue their attack on movement on the marsh surface (Hugie, 2004). TK crabs, on the other hand, spend more time actively feeding on the marsh surface, which may increase predation risk (Sih, 1980; Lima, 1990). Although there do not appear to be detrimental abnormal behaviors of PC crabs, there could still be effects on biochemistry and physiology; t hese crabs do have considerably greater mortality of early life stages (Bergey and Weis, 2008). However, they have developed tolerance to some contaminants in their environment. Callahan and Weis (1983) exposed U. pugnax from PC and TK to methylmercury during limb regeneration and found that exposed PC crabs regenerated faster than exposed TK crabs, suggesting that they have developed tolerance to this contaminant. Increased tolerance to metals has been seen in other aquatic organisms in metal-polluted areas (Brown, 1978; Bryan and Hummerstone, 1973; Klerks and Bartholomew, 1991; Wallace et al., 1998). PC crabs are also able to shift some toxic metals from their soft tissues into their exoskeleton just prior to ecdysis, as a method of depuration (Bergey and Weis 2007). Their tolerance to contaminants, combined with their ability to

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depurate them, apparently has enabled the PC crabs to adapt to their contaminated marsh ecosystem.

CONCLUSION Fiddler crabs from polluted Piles Creek showed reduced activity and reduced feeding compared with conspecifics from the reference estuary, Tuckerton. However, the altered behaviors did not appear to have adverse ecological consequences. As previously noted, PC crabs are larger, despite eating less. This may be due to enriched food, less competition (lower population density), and/or to reduced energy expenditure by being less active. Their tendency to be inactive and remain in burrows may also protect them from blue crab predators.

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REFERENCES Anderson, T., Elser, J, Hessen, D., 2004. Stoichiometry and population dynamics. Ecol. Lett. 7, 884-900. Bergey, L., Weis, J.S., 2007. Molting as a mechanism of depuration of metals in the fiddler crab, Uca pugnax. Mar. Environ. Res. 64(5), 556-562. Bergey, L., Weis, J.S., 2008. Aspects of population ecology in two populations of fiddler crabs, Uca pugnax. Mar. Biol. 154, 435-442. Boyd, W.A., Brewer, S.K., Williams, P.L., 2002. Altered Behavior of Invertebrates in Polluted Environments. In: Giacomo Dell’Omo (ed.) Behavioral Ecotoxicology, John Wiley & Sons Ltd, West Sussex. Brown, B.E., 1978. Lead detoxification by a copper-tolerant isopod. Nature 276. 388–390. Bryan, G.W., Hummerstone, L.G., 1973a. Adaptation of the polychaete Nereis diversicolor to estuarine sediments containing high concentrations of zinc and cadmium. Journal of the Marine Biological Association of the United Kingdom. 53, 839–848. Bryan, G.W., Hummerstone, L.G., 1973b. Adaptation of the polychaete Nereis diversicolor to manganese in estuarine sediments. J. Mar. Biol. Assoc. UK. 53, 859–864.

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Callahan, P., Weis, J.S., 1983. Methyl mercury effects on regeneration and ecdysis in fiddler crabs (Uca pugilator, U. pugnax) after short-term and chronic pre-exposure. Arch. Environ. Con.Tox. 12, 707–714. Caravello, H.E., Cameron, G.N., 1991. Time activity budgets of the Gulf Coast fiddler crab (Uca panacea). Am. Midl. Nat. 126(2), 403–407. Christy, J.H., 1982. Burrow structure and use in the sand fiddler crab, Uca pugilator (Bosc). Anim. Behav. 30, 687–694. Crane, J. 1975. Fiddler Crabs of the World. Princeton: Princeton University Press. Dill, L. M., 1987. Animal decision making and its ecological consequences: the future of aquatic ecology and behavior. Can. J. Zool. 65, 803–811. Frost, P., Evans-White, M., Finkel, Z., Jesnsen, T., Matzek, V., 2005. Are you what you eat? Physiological constraints on organismal stoichiometry in an elementally unbalanced world. Oikos 109, 29-39. Hessen, D.O., 2004. Too much energy? Ecology 85: 1177-1178. Hugie, D.M., 2004. A waiting game between the black-bellied plover and its fiddler crab prey. Anim. Behav. 67, 823–831. Hui, C. A., 2002. Lead burdens and behavioral impairments of the Lined Shore Crab Pachygrapus crassipes. Ecotoxicology 11, 417–421. Hyatt, G.W., 1977. Field studies of size-dependent changes in waving display and other behavior in the fiddler crab Uca pugilator (Brachyura Ocypodidate). Mar. Behav. Physiol., 4:283–292. Khoury, J.N., 1995. Behavioral and subcellular approach to understanding metal toxicity in the fiddler crabs, Ph.D. Dissertation, Graduate Center of the City University of New York, 1995. Klerks, P.L., Bartholomew, P.R., 1991. Cadmium accumulation and detoxification in a Cd-resistant population of the oligochaete Limnodrilus hoffmeisteri. Aquat. Toxicol. 19, 97–112. Krebs, C.T., Valiela, I., Harvey, G.R., Teal, J.M., 1974. Reduction of field populations of fiddler crabs by uptake of chlorinated hydrocarbons. Mar. Pollut. Bull. 5(9), 140–142. Land, M., Layne, J., 1995. The visual control of behavior in fiddler crabs. II: Tracking control systems in courtship and defence. J. Comp. Physiol. A 177, 91–103. Lima, S.L., 1998. Stress and decision-making under the risk of predation: recent developments from behavioral, reproductive and ecological perspectives. Adv. Stud. Behav. 27,215–290. Lima, S.L., 1990. Behavioral decisions made under the risk of predation: a review and prospectus. Can. J. Zool. 68, 619–640.

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Meziane, T., Sanabe, M.C., Tsuchiya, M., 2002 Role of fiddler crabs of a subtropical intertidal flat on the fate of sedimentary fatty acids. J. Exp. Mar. Biol. Ecol. 270, 191-201. Milinski, M., Heller, R., 1978. Influence of a predator on optimal foraging behavior of sticklebacks (Gasterosteus aculeatus L.). Nature 275, 642– 644. Miller, J.M., Rowe, P.M., Able, K.W., 2002. Occurrence and growth rates of young-of-year Northern Kingfish, Menticirrhus saxatilis, on ocean and estuarine beaches in Southern New Jersey. Copeia 3, 815–823. Posey, M.H., Hines, A.H., 1991. Complex predator-prey interactions within an estuarine benthic community. Ecology 72(6), 2155–2169. Powers, L.W., Cole, J.F., 1976. Temperature variation in fiddler crab microhabitats. J. Exp. Mar. Biol. Ecol. 21, 141–157. Reichmuth, J.M., Roudez, R., Glover T. and Weis J.S. 2009. Differences in prey capture behavior in populations of blue crab (Callinectes sapidus Rathbun) from contaminated and clean estuaries in New Jersey. Estuaries and Coasts 32: 298-308. Reinsel, K.A., 2004. Impact of fiddler crab foraging and tidal inundation on an intertidal sandflat: season-dependent effect in one tidal cycle. J. Exp.Mar. Biol. Ecol. 313, 1–17. Reinsel, K.A., Rittschof, D., 1995. Environmental regulation of foraging in the sand fiddler crab Uca pugilator (Bosc, 1802). J. Exp. Mar. Biol. Ecol. 187, 269–287. Ringold, P., 1979. Burrowing, root mat density, and the distribution of fiddler crabs in the eastern United States. J. Exp. Mar. Biol. Ecol. 36, 11–21. Santiago, C., 1997. Size-frequency distribution of Palaemonetes pugio in two New Jersey estuaries and predator-prey interactions with Fundulus heteroclitus. Department of Chemical Engineering, Chemistry, and Environmental Science. Newark, New Jersey Institute of Technology, 65 p. Santiago Bass, C., Bhan, S., Smith, G.M., Weis, J.S., 2001. Some factors affecting size distribution and density of grass shrimp (Palaemonetes pugio) populations in two New Jersey estuaries. Hydrobiologia 450, 231– 241. Sih, A., 1994. Predation risk and the evolutionary ecology of reproductive behaviors. J. Fish Biol. 45, 111–130. Sih, A., 1980. Optimal behavior: can foragers balance two conflicting demands? Science 210, 1041–1043.

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Skov, M.W., Hartnoll, R.G., 2002. Quantifying the density of mangrove crabs: Ocypodidae and Grapsidae. Mar. Biol. 141, 25–732. Smith, G. M., Weis, J.S., 1997. Predator-prey relationship in mummichogs (Fundulus heteroclitus (L.)): Effects of living in a polluted environment. J. Exp. Mar. Biol. Ecol. 209, 75–87. Wallace, W.G., Brouwer, T.M.H, Brouwer, M., Lopez, G.R., 2000. Alterations in Prey Capture and Induction of Metallothioneins in Grass Shrimp fed Cadmium Contaminated Prey. Environ. Toxicol. Chem. 249, 183–197. Wallace, W.G., Lopez, G.R., Levinton, J.S., 1998. Cadmium resistance in an oligochaete and its effect on cadmium trophic transfer to an omnivorous shrimp. Mar. Ecol. Prog. Ser. 172, 225–237. Weis, J.S., Samson, J., Zhou, T., Skurnick, J., Weis, P., 2001. Prey capture ability of mummichogs (Fundulus heteroclitus) as a behavioral biomarker for contaminants in estuarine systems. Can. J. Fish. Aquat. Sci. 58, 1442– 1452. Weis, J.S., Weis, P., Smith, G., Zhou, T., Santiago-Bass, C., 2001. Effects of Contaminants on Behavior: Biochemical Mechanisms and Ecological Consequences. BioScience 51, 209–217. Weis, J.S., Perlmutter, J., 1987. Effects of Tributyltin on activity and burrowing behavior of the fiddler crab, Uca pugilator. Estuaries 10(4), 342–346. Weis, J.S., Weis, P., 2004. Behavior of four species of fiddler crabs, genus Uca, in southeast Sulawesi, Indonesia. Hydrobiologia 523, 47–58. Werner, E.E., Gilliam, J.F., Hall, D.J., Mittelbach, G.G., 1983. An experimental test of the effects of predation risk on habitat use in Fish. Ecology 64, 1540–1548. Wolfrath, B., 1993. Observations on the behavior of the European fiddler crab Uca tangeri. Mar. Ecol. Prog. Ser. 100, 111–118.

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In: Crabs: Anatomy, Habitat, Editors: K. Saruwatari, M. Nishimura

ISBN: 978-1-61942-225-4 © 2012 Nova Science Publishers, Inc.

Chapter 6

CELLULAR CADMIUM TRANSPORT IN GILLS AND HEPATOPANCREAS OF UCIDES CORDATUS, A MANGROVE CRAB P. Ortega1 and F. P. Zanotto2

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1

Instituto de Biociências, Departamento de Fisiologia Geral, Universidade de São Paulo (USP), Brasil 2 Laboratório de Fisiologia Animal Comparada, Universidade Presbiteriana Mackenzie (UPM), Brasil

ABSTRACT Ucides cordatus is a mangrove crab, and has a very important role in human food consumption. Mangrove areas can be contaminated with heavy metals, like cadmium (Cd), through waste and disposal of batteries from industries. This metal reaches the animal through its gills, when is dissolved in the water, or through its hepatopancreas, from consumption of contaminated food. Because this metal does not have any physiological role for the animal, small concentrations can be extremely toxic. It is not known how cadmium enters the cells, but, because it is a divalent metal, it could enter cells together with calcium, using its plasma membrane channels to penetrate the cells. Therefore, the objective of the work was to characterize the kinetics of Cd transport. For this, the gill cells were separated by enzymatic dissociation, and the hepatopancreatic cells were dissociated by magnetic stirring, then, the cells were separated by sucrose gradient, and labeled with Fluo 3 AM. After that, the kinetics of Cd

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P. Ortega and F. P. Zanotto transport was characterized in the spectrofluorimeter, with addition of successive CdSO4 concentrations (0.5, 1.0 and 1.5 µM), respectively. Results showed a sigmoidal curve for Cd transport, suggesting that others ions, like calcium, for example, can participate in the transport of Cd.

Keywords: Transport, CdSO4, Ucides cordatus, gills, hepatopancreas.

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INTRODUCTION Crustaceans include about 30,000 species described..First, they invaded marine environments, and occupied after that freshwater and terrestrial habitats, which are extremely diverse in terms of osmoregulation (Mulford and Villena, 2000). For this, they have specialized adaptations of the epithelial cells of the gills, integument, hepatopancreas and antennal gland for the regulation and passage of molecules and ions between the haemolymph and external environment (Ahearn et al., 1999; Monteilh-Zoller et al., 1999). Crustaceans have a relative tolerance to salinity changes, especially the species that live in estuaries or tidal areas such as the mangrove crab Ucides cordatus (Rinderhagen et al., 2000). Different organs and mechanisms are involved in this regulation. The main ones are the antennal gland, which performs excretion and osmotic regulation, the epithelium of the hepatopancreas and finally the gills (Rinderhagen et al., 2000). The latter is an important organ for ion exchange with the water, having an epithelium specialized for that function. Ucides cordatus is an euryhaline crustacean. It constructs burrows in the soil surface during low tide to feed, avoiding contact with water (CastilhoWestphal et al., 2008). Its ability to maintain ionoregulatory homeostasis is possible through the osmoregulatory function of the posterior gills (CastilhoWestphal et al., 2008). This mechanism occurs through a Na+/K+-ATPase, responsible for the transepithelial movement of monovalent ions. It is found mainly in posterior gills, since, for its operation, it is necessary a large amount of mitochondria (Castilho-Westphal et al., 2008). In addition, U. cordatus has electrodense granules in hepatopancreas (GED) related to the retention of cations from heavy metals found in the environment (Castilho-Westphal et al., 2008). Thus, the gill region is found in the outer surface of the crustaceans, being the first site for osmotic and ionic regulation between the animal and the environment (Bouaricha et al 1994).

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The gill of crabs contain specialized cells that have been studied in crustaceans, especially crabs, shrimps and lobsters. It is considered that there are four to five different cell types (Lawson et al 1995; Martinez et al., 1999; Freire et al., 2008; Ortega et al., 2011):  



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

Thick cells: involved in the transport of ions, rich in mitochondria, 10 to 20 µm deep. Thin cells: they are small and contain few vacuoles, found in the anterior region of the gill, but contain large surface area, predominantly of respiratory function. Pillars cells: are multinucleated and contains many microtubules. In addition, may act as respiratory sites and ion transport. Microtubules have a supporting role for carrying hemolymph through the gill lamellae. Granular haemocytes and gill podocytes or nefrocytes: the nefrocytes areas are associated with oxygen and can remove particles from metabolic or toxic foreign molecules; the granular haemocytes are involved in coagulation, encapsulation and phagocytosis.

However, the presence of these cells can change depending on the species of crustaceans. In shrimps, lobster and crayfish, for example, there are cells of edge and flange cells. These cells have a thin cuticle that form microvilli and brochures that reduce or disappear with salinity acclimation. They have a respiratory and ion function (Freire et al., 2008). In osmoconformers marine crabs, there are thin cells which functions primarily in respiration, but these cells can act in the excretion of ammonia or ion absorption (Freire et al., 2008). On the other hand, thick or thicker cells, possessing a large number of mitochondria with a membrane sheet form or microvilli, is a typical cell for ion transport in crabs osmoregulators such as Ucides cordatus studied here (Freire et al., 2008). The hepatopancreas consists in a digestive gland, with numerous cells in single layer tubules open into the intestine, surrounded by haemolymph. The hepatopancreas has complex structure with various functions performed by different cell types, including absorptive cells, secretory, storage and undifferentiated cells. These cells are involved in the synthesis and secretion of digestive enzymes, absorption and storage of nutrients, accumulation of calcium and heavy metals and is involved in the process of excretion/detoxification (Mulford and Villena, 2000).

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The hepatopancreas is composed of four cell types: B cells, E cells, R and F cells (Chavez-Crooker et al., 2001). These cells have a major functional diversification and is involved in digestion, absorption, secretion and detoxification. The food passes from the intestine to the digestive tubule lumen of the hepatopnacreas, where the organic and inorganic solutions are carried across the epithelial layer to the haemolymph, being distributed to the rest of the body (Kamude et al., 2002). Detoxification occurs through processes of sequestration and complexation of cationic substances that are subsequently eliminated by the edge of the apical plasma membrane and, lastly, the faeces. Thus, detoxification of heavy metals such as cooper (Cu), occurs when in high concentration to prevent harmful effects to the animal (Ahearn et al., 1999). Cadmium is a transition metal, toxic, found in discarded batteries, with no apparent physiological function. Cd can accumulate in tissues in proportion with the external concentration of the metal, apparently showing no internal regulation in crustaceans (Soegianto et al., 1998). It is not an essential element for metabolic processes, is not regulated by the animal, having a concentration variation in tissues according to its exposure (Turoczy et al., 2001), and even at low concentrations can cause toxicity (Playliste et al., 1993). These metals can substitute for essential metals such as cooper (Cu) and zinc (Zn) in the functioning of enzymes and cofactors, interfering with the role of these other metals. Cadmium induces the production of metallothioneins, proteins that sequester metals, as observed for other essential metals such as Cu (Pedersen et al., 1998; Mouneyrac et al., 2001). Several studies show that high concentrations of cadmium can be lethal to crustaceans, which might cause adverse physiological effects, especially for breathing and osmoregulation (Soegianto et al., 1998). Thus, the gills, as they are crucial for respiration, acid-base balance, osmotic and ionic regulation, when in contact with high concentrations of metal, can undergo morphological damage resulting in respiratory and osmoregulatory failure (Soegianto et al., 1998). Contact with the metal occurs through the diet or through gills exposed to water (Pedersen and Bjerregaard, 1999; Nuñez-Nogueira and Rainbow, 2004). Heavy metals from industries are disposed of in coastal and estuarine areas, such as mangroves, and are subjected to contamination due to mangrove areas link with river systems and their contaminants, also contaminating the animals in those regions, such as Ucides cordatus (Harris and Santos, 2000). Possible sources of contamination are landfill, residential sewage, the disposal of batteries, effluents from smelters and metallurgical industries in the region of Cubatao in the State of Sao Paulo, Brazil (Ramos and Gerard, 2007).

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Most studies have focused on the removal of Cd from the aquatic environment and their accumulation in different animals, but little information exists on its cellular transport. The toxic metals are usually involved in geochemical processes, because competition and complexation of these metals can interfere with their availability in the water, affecting the bioavailability to the animals exposed to them (Matsuo et al., 2005). In crustaceans, the removal of metals appears to occur through the gills, where cadmium could pass through this epithelium by paracellular diffusion or transcellular routes (Pedersen and Bjerregaard, 1999). Additionally, the authors observed that calcium (Ca) competes with Cd and the influence of the latter increases with the removal of Ca from the external environment, thus increasing the toxicity of Cd. The removal of Na, in the other hand, inhibits the entry of Cd in gills of amphipods, as well as in perfused gills of crabs (Silvestre et al., 2004). Several studies also observed the effect of Cd in postmoult animals, apparently related to its interaction with Ca (Delisle and Roberts, 1994; Zanders and Rojas, 1992). The removal of Cd and Ca, and the use of radioisotopes for both ions, showed that Cd is removed from the medium via Ca channels located in apical membrane of the gills of Carcinus, after competition between the two ions (Bondgaard and Bjerregaard, 2005). The influx of Cd also appears to be dependent on salinity. The accumulation and toxic effects of Cd appear to increase in environments with low salinity or low levels of Ca (Zanders and Rojas, 1996). When there is a decrease in salinity, the amount of free Cd in the environment increases, rendering it more toxic because this metal does not complex with chloride ions that are unavailable in low salinity (Wright, 1995; Hall et al., 1995). As Cd competes with Ca, at low concentrations of Ca there is an increase of Cd influx, especially in animals that are in diluted media (Zanders and Rojas, 1996). In addition to these effects, metals in general are strong inhibitors of carbonic anhydrase, an enzyme responsible for gas exchange (Christensen and Tucker, 1976; Skaggs and Henry, 2002). Carbonic anhydrase is an enzyme central to the integrative processes of ion transport and osmoregulation in euryhaline crustaceans, and inhibition of this enzyme could potentially affect the regulation of multiple ions indirectly (Vitale et al., 1999). In summary, the Cd seems to enter crustaceans cells via Ca channels, Na+/K+ ATPase and Ca -ATPase pathways, although no studies have been actually performed at the cellular level using specific inhibitors for each type of transporter. The objective of this study was to demonstrate the kinetics of

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Cd transport through the gill and hepatopancreatic cells of Ucides cordatus using the fluorescent marker Fluo 3 AM.

METHODOLOGY Animals Ucides cordatus (Order: Decapoda, Family: Ucididae) were collected in Itanhaém, São Paulo coast, specifically at Praia dos Pescadores, and brought to the Universidade Presbiteriana Mackenzie (São Paulo campus) where they were acclimated in the vivarium of the University. The crabs were placed in tanks containing sea water, gravel, water filters and bricks to allow access to water or air. The sea water was prepared using the salt “Red Sea Salt” (Red Sea) to a final salinity of 20.

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Salines All values for the haemolymph like saline for U. cordatus are given in mM: 395 NaCl, 10 Kcl, 2.5 NaH2PO4, 2.5 NaHCO3, 3.75 Hepes, 1 Glucose, 0.9 EDTA.

Cell Preparation 8 mL of extraction solution and 200 µL of Trypsin were added to the gills. The gills were involved in the solution and kept on ice for 15 minutes. The gills were then minced with scissors in a extracting solution with 0.05% Trypsin for 15 minutes. They were then taken to the shaker bath at 30° C for 15 minutes at 100 rpm. Soon after, the gills were filtered through fine mesh of 30 µm. The reserved gills were filtered for the second digestion, using processes similar to the first digestion. The cells were centrifuged for 5 minutes, 800 rpm and 5°C. After the first centrifugation, part of the cells that sedimented (pellet), was re-suspended in extracting solution and stored on ice, consisting of just the first digestion. The second digestion was performed in the same previous parameters, using filtered and reserved gills of the first digestion.

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The cells from hepatopancreas were obtained by magnetic stirring of the tissue. It was placed on 15 mL of buffer solution. The hepatopancreas was agitated for 15 minutes.. After this procedure, the hepatopancreas was filtered in fine mesh of 30 µm in a falcon tube of 15 mL and taken to centrifugation for 5 minutes at 800 rpm. After this process, the supernatant was discarded, leaving the pellet that was re-suspended. Different cell types were separated by discontinuous sucrose gradient at concentrations of 10, 20, 30 and 40%.Subsequently, 2 mL of each concentration was placed in falcon tubes of 15 mL, starting with the largest concentrations to the lower concentrations. The cells were taken to centrifugation for 10 minutes at 1000 rpm. The cell layers were removed for the transport experiments.

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Fluorescence Measurements Cellular transport was performed after extraction of cells from the gills. These were marked with 1µL of Fluor 3 AM for 1 hour on shaker at 110 rpm at room temperature. In an ELISA plate it was used a volume of 180 µL of cell solution after being washed with the same saline solution mentioned above but without the presence of EDTA. Known concentrations of cadmium sulphate ( 0.5, 1.0 and 1.5 mM), were added at the cells and the Cd2+ induced changes in fluorescence were measured as an indication of Cd2+ uptake across the cell plasma membrane.

Data Acquisition and Collection In the KC Junior fluorimeter, the emission was 525 nm and excitation 495 nm, and the transport of cadmium was measured every 90 seconds. Curve fitting and the production of the resulting Cd2+ influx kinect constant were performed using SigmaPlot 2001 for Windows. All values reported in this work were obtained from samples of four to 14 different animals.

RESULTS Gill cells showed high viability (92.5 ± 1.7%), and were characterized in different cell types. Anterior gills had a greater amount of thin cells, while the posterior gills had a greater amount of thick and pillar cells.

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In relation to hepatopancreatic cells, they also showed high viability (79.2 ± 0.02%), and were divided according to a sucrose gradient: E cells were present on the of 10% Sucrose gradient, R and F cells on the 20 and 30% Sucrose gradient and B cells were present in the 40% Sucrose gradient. The results obtained showed that there is an influx of cadmium in the anterior and posterior gills. The graph below represents Cd transport in the anterior gill (Figure 1). There was a higher influx of the metal in anterior gill cells compared to posterior gill cells, because there was a greater increase in intracellular cadmium, measured as fluorescence unit, in relation to the concentration of cadmium that the gill cells were exposed (Figure 1).

Figure 1. Concentration of cadmium (µM) according to the change in fluorescence (RFU) in anterior gill cells.

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Figure 2. Concentration of cadmium (µM) according to the variation of fluorescence in posterior gill cells.

Figure 3. Concentration of cadmium (µM) according to the variation of fluorescence in RF1 (20% sucrose gradient) and RF2 (30% sucrose gradient) cells of the hepatopancreas.

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Hereafter, it is represented the transport in posterior gill cells. It was observed that there was also an increase in intracellular cadmium according to the concentration of cadmium (Figure 2). Now, with respect to the cells of hepatopancreas, it was observed that RF1 and RF2 cells (Figure 3) have the greatest variation of fluorescence, indicating that these cells carry the cadmium more efficiently than the other cell types. Table 2. Characteristics of the sigmoidal curve for RF1 cells and hyperbola curve for RF2 cells Cells

Function

Vmax (µM)

Km (mM)

RF1

f= a/(1+exp(-(x-x0)/b))

2645.97

0.15

RF2

f= y0+a/(1+exp(-(x-x0)/b))

2010.70

0.14

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B cells (Figure 4) have a lower cellular transport, since the variation of fluorescence recorded was lower compared with RF1 and RF2 cells. E cells showed a null variation of fluorescence change.

Figure 4. Concentration of cadmium (µM) according to the variation of fluorescence in B cells (40% sucrose gradient) of the hepatopancreas.

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DISCUSSION The anterior gills have a respiratory function. Their constituents’ cells are known as thin cells. These cells have a thin membrane over other cell tpes and have vacuoles, are also smaller compared to other cells and have a small amount of mitochondria and microtubules, and are responsible for gas transport (Freire et al., 2008). The posterior gills, in turn, have an osmoregulatory function, thus having specific cells for this function. The cells present in the posterior gills are pillar and thick cells. These cells have a large amount of mitochondria and microtubules for support. Generally, these cells are larger than the thin cells, and the large amount of mitochondria provide energy for the ion exchange process (Freire et al., 2008). In relation to the hepatopancreas, the cells present are divided into layers according to the density of each cell. E cells, because they are smaller, undifferentiated and present mitosis frequently (Chavez-Crooker et al., 2001), occupy the 10% Sucrose layer. R and F cells have similar densities and their characteristics are not recognized under the optical microscope. Thus, these cells were grouped and designated as RF cells. These cells may occupy the 20% Sucrose layer, called RF1 cells, and the 30% Sucrose layer, called RF2 cells. RF cells have a large amount of organelles, possessing a higher density than the E cells. R cells have the function of absorbing substances, and F cells play a role in secretion of enzymes, participating in the digestion of nutrients (Chavez-Crooker et al., 2001). These cells also have an osmoregulatory function, playing a role such as a detoxification site of ions and metals. B cells show big vacuoles, occupying the 40% Sucrose gradient. This cell have are more dense than the other cell types of the hepatopancreas. The vacuole play a role in storage of substances or detoxification (ChavezCrooker et al., 2001). The capture of ions or metals in these cells are performed by proteins called metalothioneins. These proteins have a sulphide group in its composition and they bind with high affinity the heavy metals, capturing these metals in vacuoles, or carrying them out to the extracellular medium (Ahearn et al., 2004). Little is known about transport of intracellular cadmium in gills cells of crabs or in hepatopancreatic cells, but it is believed that the metal enter the cell through calcium channels, competing with this ion (Silvestre et al., 2004). Cadmium is a non essential metal and toxic to crabs at certain concentrations (Ahearn et al., 2004). It is known that this metal is accumulated in gills and other organs of crabs (Soegianto et al., 1998; Turoczy et al., 2001).

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Thus it is necessary a regulation of the amount of cadmium that enters and is accumulated inside the cells, to avoid damage. It is not known which way this metal enters the cells, and results presented here suggest that a co-transport of cadmium to the interior cell could be happening because of a sigmoidal curve seen here for Cd transport. It is observed that in both posterior and anterior gills, there is an influx of cadmium through a sigmoidal curve. This curve characterizes that the metal, in this case cadmium, enters the cell in cooperation with other ions, maybe calcium or even sodium, through calcium channels or Na+ exchangers. In other words, for the influx of cadmium, it is necessary the influx of other ions so that cadmium can enter gill cells. It is known that cells of the anterior gills do not have a ionic regulation function because they are responsible for breathing (Freire et al., 2008). These gills have specialized epithelia to exchange gases, which are thin, with few mitochondria or organelles (Freire et al., 2008). Through the system of counterflow, the gills, especially the anterior ones, are in constant contact with oxygen in the water, obtaining, through diffusion, high concentrations of oxygen and eliminating carbon dioxide. Unlike anterior gills, posterior gills are responsible for osmoregulation, able to perform ion exchange (Freire et al., 2008). These cells, in contrast, have large amounts of mitochondria, carrying out ionic regulation. So, the change in fluorescence found in the anterior gills was higher in comparison to posterior ones, because cells present in anterior gill, especially thin cells, have a role in cellular respiration, apparently not performing any kind of ion regulation or exchange (Freire et al., 2008). It is possible to suggest that the anterior gills accumulate higher amounts of cadmium, since these cannot be exchanged with other ions present in the external environment, or due to the anterior gills inefficiency in osmoregulation, allowing Cd to enter the cell plasma membrane in large amounts. In contrast, the posterior gill cells have a lower variation of fluorescence than the anterior gills, due to the fact that the posterior gills have mainly thick and pillar cells, responsible for the osmoregulation and ion exchange (Freire et al., 2008). Therefore, when there is an increase of cadmium in the extracellular medium, there is an influx of this metal to the cell and the Fluo 3 AM used here only releases its fluorescence when bound with cadmium. Thus, we can correlate this aspect of the posterior gill with the accumulation of the metal. As there is the constant exchange of cadmium by other ions (calcium or sodium) present in the extracellular medium, the accumulation of this metal in the posterior gills could be kept to a minimum because of its damaging effects to the cells, unlike

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what was seen for anterior gill cells, where regulation of Cd entrance was not as effective. In relation to hepatopancreatic cells, the E cell showed very low transport of cadmium, since this cell type is responsible for the formation of other hepatopancreatic cell types, being in constant process of cell differentiation (Chavez-Crooker et al., 2001). Thus, the ionic regulatory processes do not allow any influx of Cd. Because the cells R and F have a very similar density, they were not identified in the separation performed by different concentrations of sucrose gradient. Thus, these cells were pooled and analyzed as a whole. Thus, RF1 cells (present in the layer of 20% Sucrose) and RF2 (present in the layer of 30% Sucrose) showed a similar transport of cadmium, with high variation in fluorescence. These cells are known for ionic regulation (Chavez-Crooker et al., 2001), with a large amount of organelles and mitochondria, which characterizes cells that have an osmoregulatory function. So, these cells have a high variation of fluorescence suggesting a large influx of Cd. Regarding B cells, they have a lot of vacuoles responsible for storage, digestion and absorption of nutrients. Moreover, these cells act as a detoxifier, and because of that could accumulate metals on the inside and eliminate them with existing lysosomes (Chavez-Crooker et al., 2001). Thus, these cells have a small change in fluorescence, indicating a slow influx of the metal within these cells. When cadmium crosses the cell membrane, it can bind to Fluo 3 AM, emitting fluorescence, or the metal can be captured and complexed by proteins, metallothioneins, for posterior storage of cadmium to vacuoles, which can be eliminated to the extracellular medium or degraded by lysosomal enzymes (Ahearn et al., 2004).

REFERENCES Ahearn, G. A.; Duerr, J. M.;Zhuang, Z.; Brown, R. J.; Aslamkhan, A.; Killebrew, D. A. Ion transport processes of crustacean epithelial cells. Physiol. Biochem. Zool., 72(1):1-18, 1999. Ahearn, G. A.; Mandal, P. K.; Mandal, A. Mechanisms of heavy-metal sequestration and detoxification in crustaceans: a review. J. of Comp. Physiol. B. 174(6): 439-452, 2004. Bondgaard, M. and Bjerregaard, P. Association between cadmium and calcium uptake and distribution during the moult cycle of female shore crabs, Carcinus maenas: an in vivo study. Aquat. Toxicol. 72. 17-28. 2005.

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Bouaricha, N.; Charmantier-Daures, M.; Thuet, P.; Trilles, J. P. and Charmantier G. Ontogeny of osmoregulatory structures in the shrimp Penaeus japonicus (Crustacea, Decapoda). Biol. Bull.186: 29-40. 1994. Castilho-Westphal, G. G.; Ostrensky, A.; Pie, M. R.; Boeger, W. A. The state of the art of the research on the mangrove land crab, Ucides cordatus. Arch. Veter. Science, 13, n. 2: 151-166. 2008. Chavez-Crooker, P.; Garrido, N. and Ahearn, G. A. Cooper transport by lobster hepatopancreatic epithelial cells separated by centrifugal elutriation: measurements with the fluorescent dye Phen Green. J. Exp. Biol. 204. 1433-1444. 2001. Christensen, G. and Tucker, J. Effects of selected water toxicants on in vitro activity of fish carbonic-anhydrase. Chemico-Biological Interact. 13. 181192. 1976. Delisle, P. and Roberts, M. The effect of salinity on cadmium toxicity in the estuarine Mysid mysidopsis - Bahia – roles of osmoegulation and calcium. Mar. Environ. Res. 37. 47-62. 1994. Freire, C. A.; Onken, H. and Mcnamara, J. C. Review. A structure function analysis of ion transport in crustacean gills and excretory organs. Comp. Biochem. Physiol.,A: 151( 3): 272-304, 2008. Hall, L.; Ziegenfuss, M.; Anderson, R. and Lewis, B. The effect of salinity on the acute toxicity of total and free cadmium to a Chesapeake Bay copepod and fish. Mar. Pollut. Bull. 30. 376-384. 1995. Harris, R. R. and Santos. M. C. F. Heavy metal contamination and physiological variability in the Brazilian mangrove crabs Ucides cordatus and Callinects danae (Crustacea: Decapoda). Mar. Biol. 137. 691-703. 2000. Henry, R. P. and Cameron, J. N. The role of carbonic anhydrase in respiration, ion regulation and acid-base balance in the aquatic crab Callinectes sapidus and the terresrial crab Gecarcinus lateralis. J. Exp. Biol. 103: 205-223. 1982. Kamude, C.; Grosell, M.; Higgs, D.; Wood, C.M. Copper metabolism in actively growing rainbow trout (Onorhyncus mykiss): interactions between dietary and waterborne copper uptake. J. Exp. Biol., 205:279-290, 2002. Lawson, S. L.; Jones, M. B. and Moate, R. M. Effect of copper on the ultrastructure of the gill epithelium of Carcinus maenas (Decapoda: Brachyura). Mar. Poll. Bull. 31: 63-72. 1995. Maina, J. N. Locations, ultrastructural morphology, and putative functions of the branchial podocytes of the fresh water crab Potamon niloticus –

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Savigy (Crustacea, Decapoda, Potaminidae). Tissue and Cell. 30: 5 562572, 1998. Martinez, C. B. R., Alvares, E. P., Harris, R. R., Santos, M. C. F. A morphological study on posterior gills of the mangrove crab Ucides cordatus. Tissue and Cell. 31: 3 380-389, 1999. Matsuo, A. Y. O.; Wood, C. M. and Val, A. L. Effects of copper and cadmium on ion transport and gill metal binding in the Amazonian teleost tambaqui (Colossoma macropomum) in extremely soft water. Aquat. Toxicol., 74, 351-364, 2005. Monteilh-Zoller, M.; Zonno, V.V.; Storelli, C.; Ahearn, G. Efefects of zinc on L-[H-3]proline uptake by lobster (Homarus americanus) hepatopancreatic brush-border membrane vesicles. J. Exp. Biol., 202, 3003-3010, 1999. Mouneyrac, C. Amiard-Triquet, C. Amiard, J. and Rainbow, P. Comparison of metallothionein concntrations and tissue distribution of trace metals in crabs (Pachygrapsus marmoratus) from a metal-rich stuary, in and out of the reproductive season. Comp. Biochem. Physiol. C 129, 193-209. 2001. Mulfford, A. L. and Villena, A. J. Cell cultures from crustaceans: Shrimps, crabs and crayfish. In: MOTHERSILL, C. AND AUSTIN, B. Aquatic invertebrate cell culture. Springer Verlag. Berlin. 63-134. 2000. Nuñez-Nogueira, G. and Rainbow, P. S. Cadmium uptake and accumulation by the decapod crustacean Penaeus indicus. Mar. Environ. Resear. 60. 339-354. 2005. Pedersen, S. N.; Pedersen, K. L.; Hojrup, P.; Knudsen, J. and Depledge, M. H. Induction and identification of cadmium-, zinc- and coppermetallothioneins in the shore crab Carcinus maenas (L.). Comp. Biochem. Physiol. C 120, 251-259. 1998. Pedersen, T. V. and Bjerregaard, P. Cadmium influx and efflux across perfused gilss of the shore crab, Cacinus maenas. Aquat. Toxicol., 48, 223231. 1999. Playle, R. Dixon, D. Burnison, K. Copper and cadmium-binding to fish gillsestimates of metal gill stability-constants and modeling of metal accumulation. Canadian Journal Fish Aquatic Sciences, 50, 2678-2687, 1993. Ramos, M. G. M. and Geraldo, L. P. Engenharia Sanitária Ambiental. 12: 4, Rio de Janeiro. 2007. Rinderhagen, M.; Ritterhoff, J. and Zauke, G. P. Crustaceans as bioindicators. Env. Res. Forum. 9: 161-194. 2000.

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Silvestre, F.; Trausch, G.; Pequeux A. and Devos, P. Uptake of cadmium through isolated perfused gills of the Chinese mitten crab, Eriocheir sinensis. Comp. Biochem. Physiol. A 137, 189-196. 2004. Skaggs, H. and Henry, R. Inhibition of carbonic anhydrase in the gills of two euryhaline crabs, Callinects sapidus and Carcinus maenas, by heavy metals. Comp. Biochem. Physiol. C 133, 605-612. 2002. Soegianto, A.; Charmantier-Daures, M.; Trilles, J.-P. and Charmantier, G. Impact of cadmium on the structure of gills and epipodites of the shrimp Penaeus japonicus (Crustacea: Decapoda). Aquat. Living Resour. 12 (1). 57-70. 1998. Tsai, J. R. and Lin, H. C. V-type H+-ATPase and Na+, K+-ATPase in the gills of 13 euryhaline crabs during salinity acclimation. J. Exp. Biol 210: 620627. 2006. Turoczy, N. J.; Mitchell, B. D.; Levings, A. H. and Rajendram, V. S. Cadmium, copper, mercury, and zinc concentrations in tissues of the King Crab (Pseudocarcinus gigas) from southeast Australian waters. Envir. Intern. 27. 327-334. 2001. Vitale, A.; Monserrat, J.; Castilho, P. and Rodriguez, E. Inhibitory effects of cadmium on carbonic anhydrase activity and ionic regulation of the estuarine crab Chasmagnathus granulata (Decapoda: Grapsidae). Comp. Biochem. Physiol. C 122, 121-129. 1999. Wright, D. Trace-metal and major interactions in aquatic animals. Mar. Pollut. Bull. 31, 8-18. 1995. Yang, Z. B., Zhao, Y. L., Li, N. and Yang, J. Effect of waterborne copper on the microstructures of gill and hepatopancreas in Eriocheir sinensis and is induction of metallothionein synthesis. Arch. Environ. Contam. Toxicol. 52: 222-228. 2006. Zanders, I. and Rojas, W. Cadmium accumulation, lc50 and oxygenconsumption in the tropical marine amphipod Elasmopus rapax. Mar Biol. 113, 409-413. 1992. Zanders, I. and Rojas, W. Salinity effects on cadmium accumulation in various tissues of the tropical fiddler crab Uca rapax. Environ. Pollut. 94, 293299. 1996.

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Chapter 7

CRAB INFLUENCES ON THE EXPORT OF PLANT DETRITUS FROM SALT MARSHES AND MANGROVES: A REVIEW Jorge L. Gutiérrez*

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Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Mar del Plata, Argentina Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina Grupo de Investigación y Educación en Temas Ambientales (GrIETA), Mar del Plata, Argentina and Institute of Ecosystem Studies, Millbrook, NY, US

ABSTRACT While crabs occur in perhaps most salt-marshes and mangroves worldwide, they are rarely considered in studies dealing with tidal fluxes of plant detritus from these coastal wetlands to adjacent waters. However, crabs can affect the production, availability and tidal transport of plant detritus in a variety of ways. This includes controls via both assimilatorydissimilatory mechanisms (e.g., herbivory, detritivory, seed and propagule consumption) and non assimilatory, non dissimilatory environmental modification (i.e., physical ecosystem engineering; e.g., *

E-mail address: [email protected].

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Jorge L. Gutiérrez sediment oxygenation via burrows, detritus excavation and burial, detritus trapping into burrows). Given the high densities and activity rates shown by many crab species, their effects on the export of plant detritus are expected to be important relative to overall marsh production. Therefore, the predictive capacity of models dealing with detritus export by salt marshes and mangroves is likely to be enhanced by considering crab influences.

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1. INTRODUCTION Salt marshes and mangroves are highly productive ecosystems that are intimately linked to adjacent estuarine waters by fluxes of particulate and dissolved organic matter (Adam 1990, Mitsch and Gooselink 1993, Lee 1995). A central question regarding the functioning of salt marsh and mangrove ecosystems is whether their primary production contributes to fuel trophic webs in adjacent coastal waters. While there is no single answer (see Nixon 1980, Lee 1995, Childers 2000 for reviews), we can predict that the quantity of detritus exported from these coastal wetlands will be a function of detritus availability, its exposure to vectors capable to transport it, and the presence of structures that sequester detritus on their way out of the system. Dominant vegetation, tidal regime and geomorphology are usually postulated as the most important factors causing variation in the export characteristics of tidal marshes and mangroves because of their obvious major influences on the availability and transportability of detritus (Odum et al. 1979, Nixon 1980, Gallagher et al. 1980, Findlay et al 1990, Dame and Allen 1996, Bouillon et al. 2004). Marsh invertebrates may, however, affect detritus production, its exposure to tides and subsequent transport in many ways with potentially significant consequences for marsh export. Brachyuran crabs are amongst the most conspicuous invertebrate inhabitants of salt marshes and mangroves worldwide, where they often occur at remarkably high densities (Table 1) and/or constitute an important proportion of the invertebrate biomass and secondary production (e.g., Teal 1962, Cammen et al. 1980). Given their high abundance and activity rates, crabs can be major influence on the fate of marsh primary production. Nevertheless, while there is abundant literature illustrating important effects of crabs on biological, physical and biogeochemical variables at salt marshes and mangroves, the implications of such crab activities for material export (and detritus export in particular) were rarely subject of research attention. In this chapter, I illustrate the multiple ways in which crabs can affect the tidal export

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of macrophyte-derived detritus from marshes and mangroves. This includes trophic as well as physical ecosystem engineering (i.e., the physical modification of biotic and abiotic materials by organisms; sensu Jones et al. 1994, 1997, Jones and Gutiérrez 2007) influences of crabs. Trophic influences occur via the consumption of both live and dead plant tissues. Physical ecosystem engineering influences are mediated by burrow excavation – a phenomenon that takes place in many salt marshes and mangroves worldwide (noticeable exceptions are salt marshes at the North Sea and the Pacific coasts of North and South America; Figure 1). Such influences include effects on detritus production, its accumulation as litter at the sediment surface (and thus, its exposure to tides), and its redeposition after entrainment into tidal transport.

Figure 1. Locations of 26 salt marsh studies (empty squares) and 36 mangrove studies (solid circles) documenting the presence of burrowing crabs. Locations plotted are illustrative rather than exhaustive and were obtained from: Apel and Türkay (1999), Ashtone et al. (2003), Bertness (1985), Bezerra and Matthews-Cascon (2007), Bouillon et al. (2004), Breitfuss et al. (2004), Brosseau et al. (2003), Cammen et al. (1980), Cantera et al. (1999), Castellanos and Rozas (2001) Clarke and Kerrigan (2002), Dahdou-Guebas and Koedam (2001), Delgado et al. (2001), Emmerson (2001), Eshky et al. (1995), Ewa-Oboho (1993), Fagonee (2005), Fell et al. (2003), Giani et al. (1996), Gonçalves et al. (2003), Gribsholt et al. (2003), Griffin (1971), Hanson et al. (2002) Krauss and Allen (2003), Lago (1993), Lee (1989), Lim and Heng (2007), Litulo (2004), Lu et al. (2001), McCraith et al. (2003), McGuiness (1997), Mchenga et al. (2007), McKee (1995), Micheli et al. (1991), Minchinton (2001), Minello et al. (1994), Moulton and Felder (1995), Negreiros-Fransozo et al. (2002), Nordhaus et al. (2006), O’Connor and Judge (1999), Omori et al. (1998), Ólafsson et al. (2002), Pennings et al. (1998), Prieto et al. (2004), Rivera-Monroy and Twilley (1996), Robertson (1986), Rodriguez et al. (1997), Schories et al. (2003), Shih (1995), Smith et al. (1989), Snelling (1959), Sousa and Mitchell (1999), Spivak (1997), Takeda and Kurihara (1987), Taylor and Allanson (1993), Thongtham and Kristensen (2003), Twilley et al. (1997), Valiela et al. (1974), Ward and Busch (1976), Warner (1969), Wolfrath (1992), Zimmerman and Felder (1991).

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Table 1. Examples of high crab abundance in salt marshes and mangroves along the five continents Location Salt marshes Cape Cod, MA, USA Chesapeake Bay, VA, USA North Inlet, SC, USA

Crab species

Density

Reference

Uca pugnax Uca minax

42 burrows m-2. Up to 76 burrows m-2. *

Katz (1980) Kerwin (1971)

Uca pugnax

20 to 300 burrows m-2. *

Sapelo Island, GA, USA Joseph’s Harbor, LA, USA Patos Lagoon, Brazil

Uca pugnax

88 burrows m-2

Uca longisignalis and U. spinicarpa Chasmagnathus granulatus

26 to 182 and 29 to 43 burrows m-2, respectively. § 23 burrows m-2.

Mar Chiquita Coastal Lagoon, Argentina Ria Formosa, Portugal

Chasmagnathus granulatus Uca tangeri

70 burrows m-2.

Kariega Estuary, South Africa

Cleistostoma edwarsii and Sesarma catenata Helograpsus haswellianus

386 and 47 ind. m-2, respectively.

McCraith et al. (2003) Montague (1982) Mouton and Felder (1996) Rosa and Bemvenuti (2005) Gutiérrez et al. (2006) Wolfrath (1992) Taylor and Allanson (1993) Breitfuss et al. (2004)

Aratus pisonii and Uca rapax Primarily Sesarma sulcatum

Up to 16 ind. m-2 each. *

Warner (1969)

Up to 85 crab holes m-2. *

Delgado et al. (2001)

Uca rapax

17.75 ind. m-2.

Uca thayeri

8.5 ind. m-2.

Neosarmatium meinerti

3 to 10 ind. m-2. *

Prieto et al. (2004) Bezerra and MatthewsCascon (2007) Ólaffson et al. (2002)

Neosarmatium meinerti Mictyris brevidactilus Uca annulipes

5 to 22 burrows m-2. *

Helice formosensis

26 to 36 holes m-2. *

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Moreton Bay, Australia Mangroves Port Royal, Jamaica Tempisque and Bebedero Rivers, Costa Rica Bocaripo Lagoon, Venezuela Pacoti River, Brazil

Gazi Bay, Kenya; Maruhubi and Chwaka Bays, Tanzania Mgazana, South Africa Tanshui, Taiwan Pulau Hantu, Singapore Manko, Japan

6 to 16 burrows m-2. §

More than 80 burrows m-2.

62 to 226 ind. m-2. § 7.6 to 25.5 ind. m-2. *

Emmerson (2001) Shih (1995) Lim and Heng (2007) Mchenga et al. (2007)

* Range of values indicates spatial variations. § Range of values indicates to temporal variations.

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2. INFLUENCES ON DETRITUS PRODUCTION

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2.1. Herbivory The consumption of live plant tissues by crabs can affect the magnitude of detritus export via effects on detritus production. Removal of plant biomass by herbivores often results in decreased detritus production and litter accumulation (e.g., Bazely and Jefferies 1986; Carson and Root 2000). However, in many circumstances, damage and partial consumption of plant tissues by herbivores induces the abscission and renewal of damaged tissues (e.g., Risley and Crossley 1988, Lee 1991), with a consequent increase in the rates detritus production. A few crab species feed on live tissues of salt marsh plants, including Chasmagnathus granulatus in Argentina, Uruguay and Southern Brazil (Bortolus and Iribarne 1999, Bortolus et al. 2004) and Armases cinereum in the Eastern coast of the United States (Pennings et al. 1998, Buck et al. 2003). In addition, also a small number of crab species feed on live mangrove tissues. They include tree-climbing species such as Aratus pisonii in the Atlantic and Pacific coasts of tropical America (Beever et al. 1979) and Parasesarma leptosoma in the Western Indo-Pacific (Dahdouh-Guebas 1999), which reach the mangrove canopy to feed on fresh leaves; and less arboreal species as Macrophthalmus quadratus in Indonesia, which feeds on the bark of mangrove pneumatophores (Wada and Wowor 1990). The magnitude of crab herbivory effects on detritus availability and subsequent tidal export is likely small. Herbivory is usually a minor pathway in the flow of energy and materials in salt marshes and mangroves (i.e., usually less than 20 % of the net primary production is consumed by herbivores); primarily because of the low palatability and nutritional quality of marsh and mangrove tissues (Cebrian 1999). Nevertheless, Bortolus and Iribarne (1999) observed that inclusion of the grapsid crab, Chasmagnathus granulatus, during one month in a burned marsh area previously uninhabited by crabs led to 71.5 % clipping and 87.5 % decrease in the aboveground biomass of newly-emerged cordgrass shoots. Such heavy C. granulatus grazing on cordgrass during regeneration – which was attribited to the high palatability of newly-emerged shoots – suggest important consequences for detritus production. Therefore, there are particular circumstances (regeneration of plant stands from burning in the above example) when large crab effects on plant detritus production and subsequent export could be expected.

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2.2. Seed and Propagule Consumption Crab feeding on seeds and propagules is common on mangrove forests (though not reported in salt marshes) and can affect detritus production and its availability for tidal export by altering forest regeneration and composition. Either pre- or post-dispersal consumption of mangrove propagules was observed in a variety of crab species (see examples in Table 4), primarily as a supplement of leaf consumption (see Detritus consumption). Pre-dispersal propagule consumption by crabs and insects collectively ranges between 0 and 95 % of propagule stocks in mangrove ecosystems worldwide (Farnsworth and Ellison 1997). In addition, post-dispersal propagule consumption by crabs – which was the focus of most studies to date – can occur at rates as high as 100 % consumption in eight days (Table 2), determining tree recruitment and accounting for the dominance and abundance of particular mangrove species (Smith 1987, McKee 1995, Sousa and Mitchell 1999, Delgado et al. 2001, Clarke and Kerrigan 2002, Bosire et al. 2005). Such crab effects on the abundance and dominance of mangrove species are expected to affect forest productivity and, concomitantly, overall detritus production and export. In the absence of burrows, the fine sediments that characterize salt marshes and mangroves are usually anoxic below the top few millimeters (Aller 1988, Kristensen 1988). However, crab burrows can increase the surface area of marsh and mangrove sediments several times (Table 3). In so doing, they extend the sediment-water (or sediment-air) interface; increasing the overall volume of sediments dominated by oxic conditions, and delivering oxygen to subsurface sediments (Aller 1988, Kristensen 1988). Increased oxygen availability in marsh and mangrove sediments is expected to increase primary production via a variety of pathways that are not mutually exclusive. These include: (1) increased mineral nitrogen due to enhancement of aerobic microbial transformations as mineralization and nitrification (Kristensen 1988), (2) increased nitrogen uptake due to increased root respiration (Morris 1984, Morris and Dacey 1984), (3) increased nutrient uptake due to root association with aerobic mycorrhizal symbionts (Miller and Sharitz 2000), and (4) decreased accumulation of toxic reduced compounds in soils (Koch and Mendelssohn 1989, Bradley and Morris 1990).

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2.3. Sediment Oxygenation via Burrows The construction on burrows by many crab species can affect marsh and mangrove production via the oxygenation of otherwise anaerobic sediments. Table 2. Propagule consumption rates of mangrove crabs Location

Crab species

Everglades National Park, FL, USA

Aratus pisonii and Sesarma curacaoense Goniopsis cruentata and Ucides cordatus Primarily Sesarma sulcatum

Twin Gays, Belize

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Tempisque and Bebedero Rivers, Costa Rica Punta de San Blas, Panama Punta Galeta, Panama

Goniopsis cruentata

Gazi Bay, Kenya

Goniopsis cruentata and Ucides cordatus Sesarmids

Gazi Bay and Mida Creek, Kenya Matang, Malaysia

Neosarmartium meinerti Sesarmids

Missionary Bay and Cape Ferguson, Australia Missionary Bay and Herbert River, Australia Ludmila Creek, Australia

Sesarmids

Sesarmids.

Kosrae, Micronesia

Primarily Neosarmartium meinerti Primarily Sesarma messa, S. smithii and S. fourmanoiri Not reported.

Kosrae, Micronesia

Not reported

Bowling Green Bay, Australia

Propagule consumption* 0 to 8% in 4 days

Reference

18 to 60 % in 9 days 5 to 52 % in 25 days

McKee (1995)

2 to 15 %in 4 days 3 to 43 % in 4 weeks 67 to 100 % in 8 days 100 % after 2 days 6 to 61 % in 4 days 50 to 96 % in 18 days

Smith et al. (1989) Sousa and Mitchell (1999) Bosire et al. (2005) DahdouGuebas (1997) Smith et al. (1989) Smith (1987)

20 to 49 % in 4 days 19 to 100 % in 20-22 days

Smith et al. (1989) McGuiness (1997)

22 to 100 % in 50 days

Clarke and Kerrigan (2002) Krauss and Allen (2003) Allen et al. (2003)

16.7 % in 14 days 22.4 % in 34 days

Smith et al. (1989)

Delgado et al. (2001)

* Within-site variations depend on mangrove species.

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Table 3. Increase in the surface area of salt marsh or mangrove sediments due to the presence of crab burrows Crab species

Burrow density

Increase in surface area(%)

Reference

Uca pugnax

42 burrows m-2

59

Katz (1980)

Uca pugnax

Not reported

22

Mar Chiquita Coastal Lagoon, Argentina Mangroves Bangrong, Thailand

Chasmagna thus granulatus

60-80 burrows m-2

400-600

Teal and Kanwisher (1961) Fanjul et al. (2007)

Neoepisesar ma versicolor

0.2 burrows m-2

33.6

Townsville, Australia

Sesarma messa

1 burrow (9 openings) in 0.64 m-2

593.75

Location

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Salt marshes Cape Cod, MA, USA Sapelo Island, GA, USA

Thongtham and Kristensen (2003) Stieglitz et al. (2000)

Several experimental studies demonstrate positive effects of crab burrows on plant production that can be attributed to any of the above-mentioned aerobic pathways. Montague (1982) observed increased smooth cordgrass, Spartina alterniflora, production and ammonium concentration in sediments after introduction of mud fiddler crabs, Uca pugnax, in a marsh area not inhabited by them. In the same vein, Bertness (1985) observed decreased S. alterniflora production, sediment aeration and oxidation-reduction potential after U. pugnax removal. Smith et al. (1990) found decreased cumulative forest growth (as measured by stipule fall) and increased sulphide concentrations in sediments after experimental reduction of burrowing crab densities. Daleo et al. (2007) demonstrated that 35 % of dense-flowered cordgrass Spartina densiflora growth depends on root colonization by arbuscular mycorrhizal fungi, which takes place only in the presence of crab Chasmagnathus granulatus burrows that oxygenate marsh sediments. In general, the crab burrow environment is characterized by biogeochemical conditions that favor plant growth such as increased oxidation-reduction potentials (Bertness 1985, Fanjul et al. 2007, Mchenga et al. 2007), decreased sulphide concentrations (Smith et al 1991, Nielsen et al. 2003, Thongtham and

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Kristensen 2003, Fanjul et al. 2007), increased organic matter mineralization (Gribsholt et al. 2003, Nielsen et al. 2003, Fanjul et al. 2007), and increased ammonium and nitrate concentrations (Montague 1982, Takeda and Kurihara 1987, Fanjul 2007) relative to surrounding sediments. All these biogeochemical influences of crab burrows on plant growth and production are expected to directly affect detritus production.

3. INFLUENCES ON LITTER ACCUMULATION

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3.1. Detritivory Many crab species in salt marshes and mangroves ate plant detritus. The degree to which crab detritivory affects the accumulation of detritus on the surface of salt marshes (and, thus, its availability for tidal export) is apparently low. In fact, the fraction of the detritus produced in marshes that is not exported is primarily decomposed by bacteria and fungi (Adam 1990). This suggests that detritus availability in salt marshes would be little affected by crab detritivory. In contrast, crab detritivory is clearly a major control on the availability of detritus in the floor of mangrove forests. A variety of mangrove crab species feed on the leaf litter (Linton and Greenaway 2007). These crabs can consume between 30 and 100 % of the total leaf fall in mangrove forests (Table 4). By processing an important proportion of the mangrove leaf production, these crabs enhance nutrient re-mineralization at the forest and help to retain nutrients and energy within the mangrove ecosystem (Werry and Lee 2005, Nordhaus et al. 2006). Leaf consumption by these crabs, thus, have an important role in controlling the export of particulate matter from the forests to other nearshore habitats. The contrasting importance of crab detritivory in salt marshes and mangroves cannot be explained from differences in nutritional value and/or palatability between marsh plant detritus and mangrove leaves. Both marsh plant detritus and mangrove leaves are poor in nitrogen and rich in hardlydigestible structural carbohydrates and tannins (Tenore 1983, Linton and Greenaway 2007). In both cases C-N ratios (> 25) are exceedingly large to meet the crab nutritional demands (Tenore 1983, Linton and Greenaway 2007) and, consequently, crabs usually supplement detritus consumption with foods of higher nitrogen content by means of opportunistic predation, cannibalism,

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scavenging, algae grazing, or seed and propagule consumption (e.g., DahdouGuebas et al. 1999, Buck et al. 2003, Linton and Greenaway 2007).

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Table 4. Consumption of leaf litter by mangrove crabs

Location

Crab species

Caete estuary, Brazil

Ucides cordatus

Litter consumption (% leaf fall) 81.3 §

Bragança, Brazil

Ucides cordatus

83.4 *

Guayas River estuary, Ecuador Gazi Bay, Kenya; Maruhubi and Chwaka Bays, Tanzania Gazi Bay, Kenya

Ucides occidentalis

100 *

Neosarmatium meinerti

100 *

Sesarma guttatum

Mgazana estuary, South Africa Mai Po, Hong Kong Townsville, Australia

Neosarmatium meinerti

40.3 (day) 21.7 (night) * 43.6 *

Ingham, Australia

Missionary Bay, Australia

Chiromantes spp. Primarily Sesarma messa, S. smithii and S. fourmanoiri Primarily Cleistostoma wardi, Sesarma fourmanoiri and S. molluccensis Sesarma messa

57 * 71 to 79 §

Reference Nordhaus et al. (2006) Schories et al. (2003) Twilley et al. (1997) Ólafsson et al. (2002)

Slim et al. (1997) Emmerson and McGwynne (1992) Lee (1989) Robertson and Daniel (1989)

33 §

Robertson and Daniel (1989)

28 §

Robertson (1986)

* Daily leaf fall, § Annual leaf fall.

3.2. Detritus Excavation and Burial By constructing and maintaining burrows, crabs translocate subsuperficial sediments into the marsh surface. They usually do so at very high rates, resulting in significant sediment overturning (Table 5). This has two counteracting influences on the availability of detritus at the marsh surface. Sediment excavation can result in the transport of belowground organic matter

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(e.g. live and dead roots and rhizomes) to the marsh surface (De la Cruz and Hackney 1977).

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Table 5. Sediment excavation/turnover by crabs in salt marshes and mangroves Location

Crab species

Burrow density (burrows m-2)

Sediment excavation/turnover

Reference

Salt marshes Cape Cod, MA, USA

Uca pugnax

42

Katz (1980)

North Inlet, SC, USA

Uca pugnax

40 to 300

18 % of the upper 15 cm of sediment per year 12 to 16 cm3 m-2 d-1

Sapelo Island, GA, USA Mar Chiquita Coastal Lagoon, Argentina Mar Chiquita Coastal Lagoon, Argentina Mangroves Mida Creek, Kenya

Uca pugnax

88

6.07 g m-2 d-1

Chasmagnathus granulatus

40

2.4 kg m-2 d-1

Chasmagnathus granulatus

70

547.08 g m-2 d-1

Gutiérrez et al (2006)

Neosarmatium meinerti and Cardisoma carnifex Neoepisesarma versicolor

~4

80 to 210 cm3 m-2 d-1

Micheli et al. (1991)

0.2

0.3 % of the sediment volume to a depth of 84 cm

Thongtham and Kristensen (2003)

Bangrong, Thailand

McCraith et al. (2003) Montague (1982) Iribarne et al. (1997)

However, the deposition of excavated sediments at the marsh surface can cause the burial of surface detritus (Takeda and Kurihara 1987). Gutiérrez et al. (2006) demonstrated that burrowing by Chasmagnathus granulatus in an Argentinean salt marsh decreases the organic matter content of surface sediments via the excavation of organic-poor subsurface sediments and its deposition as mounds at the marsh surface. Deposition of excavated sediments at the marsh surface by C. granulatus buries plant macrodetritus at rates that approximate those of detritus production at the marsh (i.e. 1 to 9 and 0.5 to 10 g m-2 d-1 respectively), thus leading to very low litter accumulation at the

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marsh surface (Gutiérrez et al. unpublished data). Evidence of similar processes was found in a Japanese salt marsh by Takeda and Kurihara (1987), who observed decreasing litter accumulation and increasing amounts of buried macrodetritus with increasing densities of burrowing crabs Helice tridens. Although little acknowledged, sediment excavation by crabs is likely a widespread control on detritus accumulation in salt marshes as well as in those mangroves where leaf consumption is low (e.g., Florida mangroves; McIvor and Smith 1995).

4. INFLUENCES ON DETRITUS TRANSPORT

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4.1. Detritus Trapping into Burrows Crab burrows can function as traps for particles that are transported by the overlying water (DePatra and Levin 1989, Botto and Iribarne 2000). This is specifically true for crab species that maintain their burrows open during tidal inundation (exceptions are several ocypodid species; e.g., Warren 1990, Litulo 2004). Crab burrow openings can cover an important proportion of the sediment surface and intercept bedload-transported detritus in their pathway to the adjacent coastal waters. Estimates obtained from an Argentinean salt marsh indicate that burrows of Chasmagnathus granulatus collect 4.15 and 0.3 g m-2 d-1 of sedimentary organic matter and macrodetritus (i.e., detrital particles larger than 1 cm length), respectively (Gutiérrez et al. 2006, unpublished data). In addition, organic matter collection into burrows is not restricted to salt marshes themselves but also occurs in the tidal flats that characterize the transition between marshes and the adjacent waters. Since these tidal flats are often extensive (i.e., more than 40 % of the area of the estuary; Iribarne et al. 2005) and show high crab densities (up to 80 burrows m-2) they can intercept an important proportion of marsh detritus in their way to the open estuary (Botto et al. 2006). Estimates conducted by Botto et al. (2006) indicate that these burrowed tidal flats can trap an amount of detritus equivalent to the annual production of an equally sized Spartina marsh in less than 100 days. While this kind of phenomenon was primarily investigated in Argentinean salt marshes, it is likely that any other burrowing crab species that maintain permanently open burrows in marshes, mangroves, or their fringing tidal flats have similar influences on detritus transport.

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5. CONCLUSION Crabs can potentially affect the export of plant detritus from salt marshes by affecting its production, its accumulation as litter (and, thus, its exposure to tidal flushing), or its subsequent tidal transport. Six general mechanisms of crab effect on the production, accumulation and transport of plant detritus were identified in this review, namely, herbivory, detritivory, seed or propagule consumption, sediment oxygenation via burrows, detritus excavation and burial, and detritus trapping into burrows. All these mechanisms are related to functional attributes that are pervasive among marsh and mangrove crabs (e.g., herbivory, detritivory, burrowing). In addition, these mechanisms are not necessarily mutually exclusive and can have synergistic influences on detritus export (e.g., Gutiérrez et al. 2006). While the broad global distribution of crabs in marshes and mangroves suggests that the mechanisms identified here are widespread, there is no quantitative measure of the contribution of these crab-mediated mechanisms to detritus export. This review illustrates that crab influences on detrital-related variables determining detritus export (i.e., production, exposure to tides, transport) can be big. Therefore, considering these crab-mediated mechanisms – together with the known influences of vegetation, geomorphology and tidal dynamics – is likely to enhance our capacity to predict detritus export by salt marshes and mangroves.

ACKNOWLEDGMENTS I thank Pablo Ribeiro for access to literature. This is a contribution to the programs of GrIETA and the Institute of Ecosystem Studies.

REFERENCES Adam, P. (1990) Saltmarsh ecology. Cambridge, UK: Cambridge University Press. Allen, J. A., Krauss, K. W. and Hauff, R. D. (2003) Factors limiting the intertidal distribution of the mangrove species Xylocarpus granatum. Oecologia, 135, 110-121.

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Aller, R. C. (1988) Benthic fauna and biogeochemical processes in marine sediments: The role of burrow structures. In Blackburn, T. H. and Sorensen, J. (Eds.) Nitrogen cycling in coastal marine environments (pp. 301-338). New York, NY: John Wiley and Sons. Apel, M. and Türkay, M. (1999) Taxonomic composition, distribution and zoogeographic relationships of the grapsid and ocypodid crab fauna of intertidal soft bottoms in the Arabian Gulf. Estuarine, Coastal and Shelf Science, 49, 131-142. Ashton, E. C., MacIntosh and D. J., Hogarth, P. J. (2003) A baseline study of the diversity and community ecology of crab and molluscan macrofauna in the Sematan mangrove forest, Sarawak, Malaysia. Journal of Tropical Ecology, 19, 127-142. Bazely, D. R. and Jefferies, R. L. (1986) Changes in the composition and standing crop of salt-marsh communities in response to the removal of a grazer. Journal of Ecology, 74, 93-706. Beever III, J. W., Simberloff, D. and King, L. L. (1979). Herbivory and predation by the mangrove tree crab Aratus pisonii. Oecologia, 43, 317– 328. Bertness, M. D. (1985) Fiddler crab regulation of Spartina alterniflora production on a New England salt marsh. Ecology, 66, 1042-1055. Bezerra, L. E. A. and Matthews-Cascon, H. 2007. Population and reproductive biology of the fiddler crab Uca thayeri Rathbun, 1900 (Crustacea: Ocypodidae) in a tropical mangrove from Northeast Brazil. Acta Oecologica, 31, 251-258. Bortolus, A. and Iribarne, O. O. (1999) Effects of the SW Atlantic burrowing crab Chasmagnathus granulata on a Spartina salt marsh. Marine Ecology Progress Series, 178, 79-88. Bortolus A., Laterra P. and Iribarne O. O. 2004. Crab-mediated phenotypic changes in Spartina densiflora Brong. Estuarine, Coastal and Shelf Science, 59, 97-107. Bosire, J. O., Kairo, J. G., Kazungu, J., Koedam, N., and Dahdouh-Guebas, F. (2005) Predation on propagules regulates regeneration in a high-density reforested mangrove plantation. Marine Ecology Progress Series, 299, 149-155. Botto, F. and Iribarne, O. O. (2000) Contrasting effects of two burrowing crabs (Chasmagnathus granulata and Uca uruguayensis) on sediment composition and transport in estuarine environments. Estuarine, Coastal and Shelf Science, 51, 141-151.

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Copyright © 2012. Nova Science Publishers, Incorporated. All rights reserved.

Crab Influences on the Export of Plant Detritus …

137

Botto, F., Iribarne, O. O., Gutiérrez, J. L., Bava, J., Gagliardini, A. and Valiela, I. (2006) Ecological importance of passive deposition of organic matter into burrows of the SW Atlantic crab Chasmagnathus granulatus. Marine Ecology Progress Series, 312,201-210. Bouillon, S., Moens, T., Overmeer, I., Koedam, N. and Dehairs, F. (2004) Resource utilization patterns of epifauna from mangrove forests with contrasting inputs of local versus imported organic matter. Marine Ecology-Progress Series, 278, 77-88. Bradley, P. M. and Morris, J. T. (1990) Influence of oxygen and sulfide concentration on nitrogen uptake kinetics in Spartina alterniflora. Ecology, 71, 282-287. Breitfuss, M. J., Connolly, R. M. and Dale, P. E. R. (2004) Densities and aperture sizes of burrows constructed by Helograpsus haswellianus (Decapoda: Varunidae) in saltmarshes with and without mosquito-control runnels. Wetlands, 24, 14-22. Brousseau, D. J., Kriksciun, K. and Baglivo, J. A. 2003. Fiddler crab burrow usage by the Asian crab Hemigrapsus sanguineus, in a Long Island Sound salt marsh. Northeastern Naturalist, 10, 415-420. Buck, T. L., Breed, G. A., Pennings, S. C., Chase, M. E., Zimmer, M. and Carefoot, T. H. (2003) Diet choice in an omnivorous salt-marsh crab: Different food types, body size, and habitat complexity. Journal of Experimental Marine Biology and Ecology, 292, 103-116. Cammen, L. M., Seneca, E. D. and Stroud, L. M. (1980) Energy flow through the fiddler crabs Uca pugnax and U. minax and the marsh periwinkle Littorina irrorata in a North Carolina salt marsh. American Midland Naturalist, 103, 238-250. Cantera, K. J. R., Thomassin, B.A. and Arnaud, P.M. (1999) Faunal zonation and assemblages in the Pacific Colombian mangroves. Hydrobiologia, 413, 17-33. Carson, W. P. and Root R. B. (2000) Herbivory and plant species coexistence: Community regulation by an outbreaking phytophagous insect. Ecological Monographs, 70, 73-99. Castellanos, D. L. and Rozas, L. P. (2001) Nekton use of submerged aquatic vegetation, marsh, and shallow unvegetated bottom in the Atchafalaya River Delta, a Louisiana tidal freshwater ecosystem. Estuaries, 24, 184197. Cebrian, J. (1999) Patterns in the fate of production in plant communities. American Naturalist, 154, 449-468.

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Copyright © 2012. Nova Science Publishers, Incorporated. All rights reserved.

138

Jorge L. Gutiérrez

Childers, D. L., Day, J. W. and McKellar, H. N. (2000) Twenty more years of marsh and estuarine flux studies: Revisiting Nixon (1980). In Weinstein, M. P. and Kreeger D. A. (Eds.) Concepts and controversies in tidal marsh ecology (pp. 391-424). Dordretch, The Netherlands: Kluwer Academic Press. Clarke, P. J. and Kerrigan, R. A. (2002) The effects of seed predators on the recruitment of mangroves. Journal of Ecology, 90, 728-736. Dahdouh-Guebas, F., and Koedam N. (2001) Are the northernmost mangroves of West Africa viable? – A case study in Banc d'Arguin National Park, Mauritania. Hydrobiologia, 458, 241-253 Dahdouh-Guebas, F., Giuggioli, M., Oluoch, A., Vannini, M. and Cannicci, S. (1999) Feeding habits of non-ocypodid crabs from two mangrove forests in Kenya. Bulletin of Marine Science, 64, 291–297. Dahdouh-Guebas, F., Verneirt, M., Tack, J. F., and Koedam, N. (1997) Food preferences of Neosarmatium meinerti de Man (Decapoda: Sesarminae) and its possible effect on the regeneration of mangroves. Hydrobiologia, 347, 83-89. Daleo, P., Fanjul, E., Mendez-Casariego, A., Silliman, B. R., Bertness, M. D. and Iribarne, O. O. (2007) Ecosystem engineers activate mycorrhizal mutualism in salt marshes. Ecology Letters, 10, 902-908. Dame, R. F. and Allen, D. M. (1996) Between estuaries and the sea. Journal of Experimental Marine Biology and Ecology, 200, 169-185. De la Cruz. A. A. and Hackney, C. T. (1977) Energy value, elemental composition, and productivity of belowground biomass of a Juncus tidal marsh. Ecology, 58,1165-70. Delgado, P., Hensel, P. F., Jiménez, J. A. and Day, J. W. (2001) The importance of propagule establishment and physical factors in mangrove distributional patterns in a Costa Rican estuary. Aquatic Botany, 71, 157178. DePatra, K. D. and Levin, L. A. (1989) Evidence of the passive deposition of meiofauna into fiddler crab burrows. Journal of Experimental Marine Biology and Ecology, 125, 173-192. Emmerson, W. D. (2001) Aspects of the population dynamics of Neosarmatium meinerti at Mgazana, a warm temperate mangrove swamp in the East Cape, South Africa, investigated using an indirect method. Hydrobiologia, 449, 221-229. Emmerson, W. D. and McGwynne, L. E. (1992) Feeding and assimilation of mangrove leaves by the crab Sesarma meinerti De Man in relation to leaflitter production in Mgazana, a warm temperate Southern African

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Crab Influences on the Export of Plant Detritus …

139

mangrove swamp. Journal of Experimental Marine Biology and Ecology, 157, 41-53. Eshky, A. A., Atkinson, R. J. A. and Taylor, A. C. (1995) Physiological ecology of crabs from Saudi Arabian mangrove. Marine Ecology Progress Series, 126, 83-95. Ewa-Oboho, I. (1993) Substratum preference two estuarine crabs Uca tangeri Eydoux (Ocypodidae) and Ocypode cursor Linne (Ocypodidae) found in a Nigeria mangrove ecosystem. Hydrobiologia, 271, 119–127. Fagoonee, I. (2005) Coastal marine ecosystems of Mauritius. Hydrobiologia, 208, 55-62. Fanjul, M. E, Grela, M. A. and Iribarne, O. O. (2007) Effects of the dominant SW Atlantic intertidal burrowing crab Chasmagnathus granulatus on sediment chemistry and nutrient distribution. Marine Ecology Progress Series, 341, 177–190. Farnsworth, E. J. and Ellison, A. M. (1997) Global patterns of pre-dispersal propagule predation in mangrove forests. Biotropica, 29, 318-330. Fell, P. E., Warren, R. S., Light, J. K., Rawson, R. L. and Fairley, S. M. (2003) Comparison of fish and macroinvertebrate use of Typha angustifolia, Phragmites australis, and treated Phragmites marshes along the lower Connecticut River. Estuaries, 26, 534-551. Findlay, S. E. G., Howe, K. and Austin, H. K. (1990) Comparison of detritus dynamics in two tidal freshwater wetlands. Ecology, 71, 288-295. Gallagher, J. L., Reimold, R. J., Linthurst, R. A. and Pfeiffer, W. J. (1980) Aerial production, mortality, and mineral accumulation: Export dynamics in Spartina alterniflora and Juncus roemerianus stands. Ecology, 61, 303312. Giani, L., Bashan, Y., Holguin, G., and Strangmann, A. (1996) Characteristics and methanogenesis of the Balandra lagoon mangrove soils, Baja California Sur, Mexico. Geoderma, 72, 149-160. Gonçalves F., Ribeiro R., and Soares A.M.V.M. (2003) Comparison between two lunar situations on emission and larval transport of decapod larvae in the Mondego estuary (Portugal). Acta Oecologica, 24, 183-190. Gribsholt, B., Kostka, J. E. and Kristensen, E. (2003) Impact of fiddler crabs and plant roots on sediment biogeochemistry in a Georgia saltmarsh. Marine Ecology Progress Series, 259, 237-251. Griffin, D. (1971) The ecological distribution of grapsid and ocypodid crabs (Crustacea: Brachyura) in Tasmania. Journal of Animal Ecology, 40, 597– 621.

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140

Jorge L. Gutiérrez

Gutiérrez, J. L., Jones, C. G., Groffman, P. M., Findlay, S. E. G., Iribarne, O. O., Ribeiro, P. D. and Bruschetti, C. M. (2006) The contribution of crab burrow excavation to carbon availability in superficial salt-marsh sediments. Ecosystems, 9, 647-658. Hanson, S. R., Osgood, D. T. and Yozzo, D. J. (2002) Nekton use of a Phragmites australis marsh on the Hudson River, New York, USA. Wetlands, 22, 326-337. Iribarne, O. O., Bortolus, A. and Botto, F. (1997) Between-habitat differences in burrow characteristics and trophic modes in the burrowing crab Chasmagnathus granulata. Marine Ecology Progress Series, 155,137145. Iribarne, O. O., Bruschetti, M., Escapa, M., Bava, J., Botto, F., Gutiérrez, J. L., Palomo, G., Delhey, K., Petracci, P. and Gagliardini, A. (2005) Small- and large-scale effect of the SW Atlantic burrowing crab Chasmagnathus granulatus on habitat use by migratory shorebirds. Journal of Experimental Marine Biology and Ecology, 315, 87-101. Jones, C. G., Lawton, J. H. and Shachak, M. (1994) Organisms as ecosystem engineers. Oikos, 69, 373-386. Jones, C. G., Lawton, J. H. and Shachak, M. (1997) Positive and negative effects of organisms as ecosystem engineers. Ecology, 78, 1946-1957. Jones, C. G., and Gutiérrez, J. L. (2007) On the meaning, usage and purpose of the ecosystem engineering concept. In Cuddington, K., Byers, J., Hastings, A., and Lambrinos, J. (Eds.). Ecosystem Engineers: Plants to Protists (pp. 3-24). New York, NY, USA: Academic Press. Katz, L. C. (1980) Effects of burrowing by the fiddler crab Uca pugnax (Smith). Estuarine, Coastal and Marine Science, 11, 233-237. Kerwin, J. A. (1971) Distribution of the fiddler crab (Uca minax) in relation to marsh plants within a Virginia estuary. Chesapeake Science 12, 180-183. Koch M. S. and Mendelssohn, I. A. (1989) Sulphide as a soil phytotoxin: Differential responses in two marsh species. Journal of Ecology, 77, 565578. Krauss, K. W, and Allen, J. A. (2003) Factors influencing the regeneration of the mangrove Bruguiera gymnorrhiza (L.) Lamk. on a tropical Pacific island. Forest Ecology and Management, 176, 49-60. Kristensen, E. (1988) Benthic fauna and biogeochemical processes in marine sediments: Microbial activities and fluxes. In Blackburn, T. H. and Sorensen, J. (Eds.) Nitrogen cycling in coastal marine environments (pp. 275-299). New York, NY: John Wiley and Sons.

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Copyright © 2012. Nova Science Publishers, Incorporated. All rights reserved.

Crab Influences on the Export of Plant Detritus …

141

Lago, R. P. (1993) Tidal exchange of larvae of Sesarma catenata (Decapoda, Brachyura) in the Swartkops estuary, South Africa. South African Journal of Zoology, 28, 182-191. Lee, S. Y. (1989) The importance of Sasarminae crabs Chiromanthes spp. and inundation frequency on mangrove (Kandelia candel (L.) Druce) leaf litter turnover in a Hong Kong tidal shrimp pond. Journal of Experimental Marine Biology and Ecology, 131, 23-43. Lee, S. Y. (1991) Herbivory as an ecological process in a Kandelia candel (Rhizophoraceae) mangal in Hong Kong. Journal of Tropical Ecology, 7, 337-348. Lee, S. Y. (1995) Mangrove outwelling: A review. Hydrobiologia, 295, 203212. Lim, S. S. L. and Heng, M. M. S. (2007) Mangrove micro-habitat influence on bioturbative activities and burrow morphology of the fiddler crab, Uca annulipes (H. Milne Edwards, 1837) (Decapoda, Ocypodidae). Crustaceana, 80, 31-45. Linton, S. M. and Greenaway, P. (2007) A review of feeding and nutrition of herbivorous land crabs: Adaptations to low quality plant diets. Journal of Comparative Physiology B – Biochemical, Systemic and Environmental Physiology, 177, 269-286. Litulo, C. (2004) Fecundity of the pantropical fiddler crab Uca annulipes (H. Milne Edwards, 1837) (Brachyura: Ocypodidae) at Costa do Sol Mangrove, Maputo Bay, Southern Mozambique. Western Indian Ocean Journal of Marine Science, 3, 87–91. Lu, J. J., He, W. S., Zhou, K. J., Tang, Y. W., Ye, S. F. and Sun, P. Y. (2001) Behavior of Zn, Cu, Pb and Cd in biota of Yangtze Estuary. Science in China Series B-Chemistry, 44, 165-172. McCraith, B. J., Gardner, L. R., Wethey, D. S. and Moore, W.S. 2003. The effect of fiddler crab burrowing on sediment mixing and radionuclide profiles along a topographic gradient in a southeastern salt marsh. Journal of Marine Research, 61, 359-390. McGuinness, K. A. (1997) Seed predation in a tropical mangrove forest: A test of the dominance- predation model in Northern Australia. Journal of Tropical Ecology, 13, 293-302. Mchenga, I. S. S., Mfilinge, P. L. and Tsuchiya. M. (2007) Bioturbation activity by the grapsid crab Helice formosensis and its effects on mangrove sedimentary organic matter. Estuarine, Coastal and Shelf Science, 73, 316-324.

Crabs: Anatomy, Habitat and Ecological Significance : Anatomy, Habitat and Ecological Significance, Nova Science

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142

Jorge L. Gutiérrez

McIvor, C. C. and Smith, T. J. (1995) Differences in the crab fauna of mangrove areas at a Southwest Florida and a Northeast Australia location: Implications for leaf litter processing. Estuaries, 18, 591-597. McKee, K. L. (1995) Mangrove species distribution and propagule predation in Belize: An exception to the dominance predation hypothesis. Biotropica, 27, 334-345. Micheli, F., Gherardi, F. and Vannini, M. (1991). Feeding and burrowing ecology of two East African mangrove crabs. Marine Biology, 111, 247254. Miller, S.P. and Sharitz, R.R. (2000) Manipulation of flooding and arbuscular mycorrhizal formation influences growth and nutrition of two semiaquatic species. Functional Ecology, 14, 738–748. Minello, T. J., Zimmerman, R. J. and Medina, R. (1994) The importance of edge for natant macrofauna in a created salt-marsh. Wetlands, 14, 184198. Minchinton, T. E. (2001) Canopy and substratum heterogeneity influence recruitment of the mangrove Avicennia marina. Journal of Ecology, 89, 888-902. Mitsch, W. J. and Gosselink, J. G. (1993) Wetlands. New York, NY: Van Nostrand Reinhold. Montague, C. L. (1982) The influence of fiddler crab burrows and burrowing on metabolic processes in salt marsh sediments. In Kennedy, V. S. (Ed.) Estuarine comparisons (pp. 283-301). New York, NY: Academic Press. Morris, J. T. (1984) Effects of oxygen and salinity on ammonia uptake by Spartina alterniflora Loisel and Spartina patens (Aiton) Muhl. Journal of Experimental Marine Biology and Ecology, 78, 87-98. Morris, J. T. and Dacey, J. W. H. (1984) Effects of O2 on ammonium uptake and root respiration by Spartina alterniflora. American Journal of Botany, 71, 979-985. Negreiros-Fransozo, M. L., Delevati-Colpo, K., and Costa T. M. (2002) Allometric growth in the fiddler crab Uca thayeri (Brachyura, Ocypodidae) from a subtropical mangrove. Journal of Crustacean Biology, 23, 273-279. Nielsen, O. I., Kristensen, E. and MacIntosh, D. J. (2003) Impact of fiddler crabs (Uca spp.) on rates and pathways of benthic mineralization in deposited mangrove shrimp pond waste. Journal of Experimental Marine Biology and Ecology, 289, 59-81. Nixon, S. W. (1980) Between coastal marshes and coastal waters: A review of twenty years of speculation and research on the role of salt marshes in

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Copyright © 2012. Nova Science Publishers, Incorporated. All rights reserved.

Crab Influences on the Export of Plant Detritus …

143

estuarine productivity and water chemistry. In Hamilton, P., MacDonald, K. B. (Eds.) Estuarine and wetland processes. (pp. 437-525). New York, NY: Plenum Press. Nordhaus, I., Wolff, M. and Diele, K. (2006) Litter processing and population food intake of the mangrove crab Ucides cordatus in a high intertidal forest in Northern Brazil. Estuarine, Coastal and Shelf Science, 67, 239250. O'Connor, N. J. and Judge, M. L. (1999) Cues in salt marshes stimulate molting of fiddler crab Uca pugnax megalopae: More evidence from field experiments. Marine Ecology-Progress Series, 181, 131-139. Odum, W. E., Fisher, J. S. and Pickral, J. C. (1979) Factors controlling the flux of particulate organic carbon from estuarine wetlands. In Livingston, R. C. (Ed.). Ecological processes in coastal marine systems (pp. 69-80). New York, NY: Plenum Press. Ólafsson, E., Buchmayer. S. and Skov, M. W. (2002) The East African decapod crab Neosarmatium meinerti (de Man) sweeps mangrove floors clean of leaf litter. Ambio, 31, 569-573. Omori, K., Irawan, B., and Kikutani, Y. (1998) Studies on the salinity and desiccation tolerances of Helice tridens and Helice japonica (Decapoda: Grapsidae). Hydrobiologia, 386, 27-36. Pennings, S. C., Carefoot, T. H., Siska, E. L., Chase, M. E. and Page, T. A. (1998) Feeding preferences of a generalist salt-marsh crab: Relative importance of multiple plant traits. Ecology, 79, 1968-1979. Prieto, A. S., Ruiz, L. J. and Montes, A. (2004) Abundancia y morfometría de una población de Uca rapax rapax (Brachyura: Ocypodidae) en la Laguna de Bocaripo, Estado Sucre, Venezuela. Boletín del Centro de Investigaciones Biológicas, 38, 81-93. Risley, L. S. and Crossley, D. A. (1988) Herbivore-caused greenfall in the Southern Appalachians. Ecology, 69, 1118-1127. Rivera-Monroy V, H. and Twilley R. R. (1996) The relative role of denitrification and immobilization in the fate of inorganic nitrogen in mangrove sediments (Terminos Lagoon, Mexico). Limnology and Oceanography, 41, 284-296. Robertson, A. I. (1986) Leaf-burying crabs: Their influence on energy-flow and export from mixed mangrove forests (Rhizophora spp.) in Northeastern Australia. Journal of Experimental Marine Biology and Ecology, 102, 237-248.

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144

Jorge L. Gutiérrez

Robertson, A. I. and Daniel, P. A. (1989) The influence of crabs on litter processing in high intertidal mangrove forests in tropical Australia. Oecologia, 78, 191-198. Rodriguez, A., Drake, P. and Arias, A. M. (1997) Reproductive periods and larval abundance patterns of the crabs Panopeus africanus and Uca tangeri in a shallow inlet (SW Spain). Marine Ecology-Progress Series, 149, 133-142. Rosa, L. C. and Bemvenuti, C. E. (2005) Effects of the burrowing crab Chasmagnathus granulata (Dana) on meiofauna of estuarine intertidal habitats of Patos Lagoon, Southern Brazil. Brazilian Archives of Biology and Technology, 48, 267-274. Schories D., Barletta-Bergan, A., Barletta, M., Krumme, U., Mehlig, U. and Rademaker, V. (2003) The keystone role of leaf-removing crabs in mangrove forests of North Brazil. Wetlands Ecology and Management, 11, 243-255. Shih, J. T. (1995) Population densities and annual activities of Mictyris brevidactylus (Stimpson, 1858) in the Tanshui mangrove swamp of Northern Taiwan. Zoological Studies, 34, 96-105. Slim, F. J., Hemminga, M. A., Ochieng, C., Jannink, N. T., de la Moriniere, E. C. and van der Velde, G. (1997) Leaf litter removal by the snail Terebralia palustris (Linnaeus) and sesarmid crabs in an East African mangrove forest (Gazi Bay, Kenya). Journal of Experimental Marine Biology and Ecology, 215, 35-48. Smith, T. J. (1987) Seed predation in relation to tree dominance and distribution in mangrove forests. Ecology, 68, 266-273. Smith, T. J., Chan, H. T.; McIvor, C. C., and Robblee, M. B. (1989) Comparisons of seed predation in tropical, tidal forests from three continents. Ecology, 70, 146-151. Smith, T. J., Boto, K. G., Frusher, S. D. and Giddins, R. L. (1991). Keystone species and mangrove forest dynamics: The influence of burrowing crabs on soil nutrient status and forest productivity. Estuarine, Coastal and Shelf Science, 33, 419-432. Snelling, B. (1959) The distribution of intertidal crabs in the Brisbane River. Australian Journal of Marine and Freshwater Research, 10, 67–83. Sousa, W. P., and Mitchell, B. J. (1999) The effect of seed predators on plant distributions: Is there a general pattern in mangroves? Oikos, 86, 55-66. Spivak, E. D. (1997) Cangrejos estuariales del Atlántico sudoccidental (25º41ºS) (Crustacea: Decapoda: Brachyura). Investigaciones Marinas Valparaíso, 25, 105-120.

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Crab Influences on the Export of Plant Detritus …

145

Stieglitz, T., Ridd, P. and Muller, P. (2000) Passive irrigation and functional morphology of crustacean burrows in a tropical mangrove swamp. Hydrobiologia, 421, 69-76. Takeda, S. and Kurihara, Y. (1987) The effects of burrowing of Helice tridens (De Haan) on the soil of a salt marsh habitat. Journal of Experimental Marine Biology and Ecology, 113, 79-89. Taylor, D. I. and Allanson, B. R. (1993) Impacts of dense crab populations on carbon exchanges across the surface of a salt marsh. Marine Ecology Progress Series, 101, 119-129. Teal, J. M. (1962) Energy flow in the salt marsh ecosystem of Georgia. Ecolog,y 43, 614-624. Teal, J. M. and Kanwisher, J. (1961) Gas exchange in a Georgia salt marsh. Limnology and Oceanography, 6, 388-399. Tenore, K. R. (1983) What controls the availability to animals of detritus derived from vascular plants: Organic nitrogen enrichment or carbon availability? Marine Ecology Progress Series, 10, 307-309. Thongtham, N. and Kristensen, E. (2003) Physical and chemical characteristics of mangrove crab (Neoepisesarma versicolor) burrows in the Bangrong mangrove forest, Phuket, Thailand with emphasis on behavioural response to changing environmental conditions. Vie et Milieu, 53, 141-151. Twilley, R. R., Pozo, M., García, V. H., Rivera-Monroy, V. H., Zambrano, R. and Bodero, A. (1997) Litter dynamics in riverine mangrove forests in the Guayas River estuary, Ecuador. Oecologia, 111, 109-122. Valiela, I., Babiec, D. F., Atherton, W., Seitzinger, S. and Krebs, C. (1974) some consequences of sexual dimorphism - feeding in male and female fiddler crabs, Uca pugnax (Smith). Biological Bulletin, 147, 652-660. Wada, K. and Wowor, D. (1990) Foraging on mangrove pneumatophores by ocypodid crabs. Journal of Experimental Marine Biology and Ecology, 134, 89-100. Ward, D. V. and Busch D. A. (1976). Effects of temefos, an organophosphorous insecticide, on survival and escape behavior of marsh fiddler crab Uca pugnax. Oikos, 27, 331-335. Warner, G. F. (1969) The occurrence and distribution of crabs in a Jamaican mangrove swamp. Journal of Animal Ecology, 38, 379-389. Warren, J. H. (1990) Role of burrows as refuges from subtidal predators of temperate mangrove crabs. Marine Ecology Progress Series, 67, 295-299.

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Jorge L. Gutiérrez

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Werry, J. and Lee, S. Y. (2005) Grapsid crabs mediate link between mangrove litter production and estuarine planktonic food chains. Marine Ecology Progress Series, 293, 165-176. Wolfrath, B. (1992) Burrowing of the fiddler crab Uca tangeri in the Ria Formosa in Portugal and its influence on sediment structure. Marine Ecology Progress Series, 85, 237-243. Zimmerman, T. L. and Felder, D. L. (1991) Reproductive ecology of an intertidal brachyuran crab, Sesarma sp. (nr. reticulatum), from the Gulf of Mexico. Biological Bulletin, 181, 387-401.

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INDEX

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A acid, x, 12, 17, 34, 72, 73, 77, 79, 80, 81, 82, 84, 86, 110, 120 acquired immunity, 9 acrosome, x, 72, 73, 74, 80, 82, 83, 84, 85, 86, 87 activity level, x, 89, 91, 94 activity rate, xi, 124 adaptations, 108 Africa, 3, 126, 132, 138, 141 age, 14, 15, 52 aggregation, 58 aggression, 92, 94, 96, 97, 98 aggressive behavior, 91 alanine, 34 Alaska, 69 algae, 91, 132 amino acids, viii, 28, 33, 34, 35, 36, 46, 79 ammonia, 109, 142 ammonium, 33, 130, 142 androgenic gland, 73 anhydrase, 111, 120, 122 ANOVA, 94, 95 antibody, 13 antigen, 88 aquaculture, 3, 18, 37 aquaria, 33, 93 aquarium, 34, 93 aquatic species, vii, 1, 2, 5, 17

arbuscular mycorrhizal fungi, 130 Argentina, 123, 126, 127, 130, 133 arginine, 34 Artemia, 90 arthropods, 20 Asia, 3, 4, 12, 20, 22, 23 Asian countries, 2, 13 ASS, 23 assessment, 46, 68 assimilation, 138 asymptomatic, vii, 1, 3, 6, 16, 18, 19 avian, 100, 101 awareness, 17, 68 axon terminals, 74, 76

B bacteria, 91, 100, 131 base, 39, 40, 110, 120 behavioral change, 90 behaviors, 91, 94, 96, 97, 98, 100, 101, 102, 104 Beijing, 88 benefits, viii, 2 bias, 58 bioassay, 6, 11, 33 bioavailability, 111 biochemistry, 101 bioindicators, 121 biological activity, 76

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148

Index

biomass, 124, 127, 138 biotic, 125 birds, 3, 14, 17 body size, 137 body weight, 77 bones, 37 Brazil, 68, 110, 126, 127, 132, 136, 143, 144 breathing, 110, 118 breeding, 72, 76, 85 by-products, 33, 37, 77

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C Ca2+, x, 72, 83, 84, 86 cadmium, vii, xi, 102, 105, 107, 110, 111, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122 calcium, xi, 5, 12, 107, 109, 111, 117, 118, 119, 120 caloric intake, 52 carapace, 3, 4, 6, 40, 42, 45, 51, 52, 55, 93 carbohydrates, 131 carbon, 118, 140, 143, 145 carbon dioxide, 118 case study, 138 causation, 13 cell culture, 121 cell differentiation, 119 cephalothorax, 12 challenges, 7, 8, 10, 11, 19 changing environment, 145 chemical, 33, 35, 46, 145 chemical characteristics, 145 chemicals, 34 chicken, 33 China, 3, 4, 6, 21, 22, 29, 71, 72, 87, 88, 141 chlorinated hydrocarbons, 103 chlorine, 12 chromatography, ix, 71, 75 classification, ix, 12, 14, 20, 49, 57 climates, 36 clinical symptoms, 2, 6 C-N, 131

colonization, 130 color, 3, 4, 14 combustion, 95 commercial, 3, 8, 11, 16, 28, 29, 30, 33, 37, 42, 43, 45, 47, 51, 52, 55, 56, 85 communication, 100 communities, 91, 136, 137 community, 19, 90, 104, 136 competition, 32, 66, 100, 102, 111 composition, 35, 47, 59, 79, 117, 128, 136, 138 compounds, 33, 128 connective tissue, 74 consumption, xi, 5, 12, 46, 107, 122, 123, 125, 127, 128, 129, 131, 132, 134, 135 consumption rates, 129 containers, 95 contaminant, 92, 101 contaminated food, xi, 107 contaminated sites, 90 contaminated water, 11, 17 contamination, 17, 90, 110, 120 control group, 7, 16, 80, 84 controversies, 138 cooperation, 77, 118 copper, 102, 120, 121, 122 Costa Rica, 126, 129, 138 courtship, 91, 103 covering, 50 crab behavior, viii, 28, 39, 40, 41 crop, 36, 136 cryopreservation, x, 72, 83, 84, 85, 86, 87 cultivation, 18 culture, 17, 18, 20, 121 cuticle, 5, 109 cycles, 16, 23 cycling, 136, 140 cytometry, 87 cytoplasm, 12, 74, 80, 82

D data collection, 57 death rate, 76 defence, 103

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149

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Index degradation, 80 Delta, 20, 137 demography, 69 denitrification, 143 Department of Fisheries and Oceans Canada (DFO), ix, 49 dephosphorylation, 82 deposition, 133, 137, 138 depth, viii, 27, 52, 56, 57, 58, 60, 61, 62, 64, 66, 67, 73, 95, 133 desiccation, 143 detection, 16, 17, 22, 32, 39 detoxification, 102, 103, 109, 110, 117, 119 diagnostic markers, 21 diet, 19, 66, 90, 100, 110 diffusion, 111, 118 digestion, 110, 112, 117, 119 digestive enzymes, 109 dimorphism, 52, 145 discrimination, 57 diseases, vii, 1, 2, 5, 17, 20, 21, 23 dispersion, 58 dissociation, xi, 107 distribution, vii, ix, 23, 33, 50, 56, 58, 60, 62, 63, 64, 65, 66, 67, 68, 69, 75, 91, 104, 119, 121, 135, 136, 139, 142, 144, 145 diversification, 110 diversity, 21, 50, 64, 136 DNA, 5, 11, 12, 14, 16, 21 dominance, 128, 141, 142, 144

E East Asia, 13 ecology, 22, 68, 102, 103, 104, 135, 136, 138, 139, 142, 146 economics, 50 ecosystem, vii, ix, xi, 2, 3, 17, 19, 22, 49, 50, 64, 68, 102, 123, 125, 131, 137, 139, 140, 145 ecotoxicological, 92 Ecuador, 13, 22, 132, 145 effluents, 110 egg, 5, 73, 77, 79, 92

electron, ix, 16, 71, 72, 74, 76, 80 electron microscopy, x, 16, 72, 80 electrophoresis, x, 15, 16, 72, 77, 83 ELISA, 113 emission, 113, 139 encapsulation, 109 endocrine, 73, 85 energy, x, 30, 90, 101, 102, 103, 117, 127, 131, 143 energy expenditure, x, 90, 101, 102 engineering, xi, 123, 125, 140 England, 136 environment, x, xi, 46, 60, 64, 79, 89, 101, 105, 108, 111, 118, 130 environmental conditions, 145 environments, x, 17, 89, 91, 111 enzymes, 80, 82, 109, 110, 117, 119 epidemiology, 19 epithelia, 7, 118 epithelial cells, 108, 119, 120 epithelium, 108, 111, 120 ester, 80 estuarine environments, 136 estuarine systems, 105 European market, 17 European Union (EU), 2 Everglades, 129 evidence, 12, 21, 24, 67, 101, 143 evolution, 70 excitation, 113 excretion, 108, 109 exoskeleton, 101 expenditures, x, 90 experimental condition, vii, 1, 6 exploitation, 45, 55, 56 exposure, 8, 9, 19, 103, 110, 124, 125, 135 external environment, 108, 111, 118 extraction, x, 72, 83, 112, 113 extracts, 12, 17, 18, 74, 83

F Fairbanks, 69 farmers, viii, 2, 3, 17, 18 FAS, 84

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150

Index

fatty acids, 104 fauna, 70, 136, 140, 142 fertilization, 73, 74, 79, 82, 85, 88 fiddler crabs, vii, x, 35, 89, 91, 92, 99, 100, 101, 102, 103, 104, 105, 130, 137, 139, 142, 145 fights, 92 filters, 112 fish, viii, 3, 27, 28, 33, 35, 36, 37, 38, 43, 44, 46, 47, 70, 90, 101, 120, 121, 139 fisheries, 3, 28, 29, 30, 39, 43, 44, 46, 50, 51, 52, 55, 56 fishing, viii, 27, 28, 29, 30, 32, 35, 36, 41, 42, 43, 44, 45, 46, 47, 50, 52, 67 flooding, 142 flora and fauna, 70 fluid, 77, 79 fluorescence, 113, 114, 115, 116, 118, 119 fluorimeter, 113 follicle, 15 food, xi, 3, 5, 32, 33, 34, 35, 38, 39, 46, 47, 91, 93, 100, 102, 107, 110, 137, 143, 146 food chain, 146 food intake, 143 food web, 3, 91 formation, 24, 119, 142 fragments, 15 freezing, x, 72, 83, 84 frequency distribution, 104 freshwater, 5, 108, 137, 139 frontal lobe, 3, 4 fungi, 130, 131 fusion, 73

G gamete, 86 gametogenesis, 14, 15 gel, x, 15, 16, 72, 77, 83 gene expression, 82 genes, 12, 20 genome, 20 genus, 3, 5, 12, 20, 21, 47, 55, 57, 105 Georgia, 139, 145

gill, xi, 20, 29, 107, 108, 109, 112, 114, 115, 116, 118, 120, 121, 122 gland, ix, 71, 73, 74, 75, 108, 109 glial cells, 74 glucose, 34 glycine, 34 glycoproteins, 21, 73, 79 Gomori reaction, x, 72, 80 granules, 74, 76, 81, 82, 108 grass, 90, 104 grazing, 127, 132 grouping, 58 growth, x, 3, 46, 90, 100, 101, 104, 130, 142 growth rate, 3, 104 guidelines, 18 Gulf Coast, 103 Gulf of Mexico, 146

H habitat, vii, ix, 50, 65, 66, 67, 68, 90, 105, 137, 140, 141, 145 habitats, ix, 20, 49, 108, 131, 144 hardness, 57 harmful effects, 110 harvesting, viii, 27, 29, 30, 42, 43 health, 14, 15, 16 health status, 15 heavy metals, xi, 107, 108, 109, 110, 117, 122 height, 94, 95 Hermit Crabs (Pagurus spp.), ix, 50 heterogeneity, 142 histology, 16 history, vii, viii, 1, 7, 9, 11, 18, 27, 30 history-dependent manners, vii, 1 homeostasis, 108 Hong Kong, 3, 132, 141 horizontal transmission, 5, 12, 14 hormone, 15, 73, 74 hormones, 15 host, 5, 12, 13, 20, 22 human, xi, 38, 73, 87, 88, 107 hunger state, viii, 27 hydrocarbons, 103

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Index

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I immobilization, 143 immune response, 17 immunity, 9, 18, 19 immunofluorescence, 16 immunoprecipitation, 83 impairments, 90, 92, 103 imports, 2, 28 improvements, 45 in vitro, 74, 120 in vivo, 16, 76, 119 India, 20, 22 Indonesia, 3, 4, 20, 105, 127 industries, xi, 18, 107, 110 industry, 29, 72 infection, vii, 1, 2, 5, 6, 7, 8, 9, 10, 11, 12, 13, 15, 17, 19, 22 inhibition, 111 injections, 7 inoculation, 7, 14, 15 inoculum, 16 insecticide, 145 insects, 14, 17, 128 inspections, 19 integument, 108 interface, 128 intestine, 7, 109, 110 intramuscular injection, vii, 1, 6, 9, 11, 15 invertebrates, 9, 90, 124 iodine, 12 ion transport, 109, 111, 120, 121 ions, xi, 108, 109, 111, 117, 118 irrigation, 145 isolation, 87 issues, 6, 11, 56

J Jamaica, 126 Japan, 3, 27, 28, 29, 30, 36, 47, 72, 126

K K+, 108, 111, 122 Kenya, 126, 129, 132, 133, 138, 144 kill, 44 kinetics, xi, 107, 111, 137 knots, 56 Korea, 29, 40

L landings, 52 larvae, 19, 76, 139, 141 lead, 45 legislation, 23 legs, 3, 4, 33, 34, 51, 91 lesions, 8, 14 lethargy, 6 life cycle, 16 lifetime, 44 ligand, 86 light, 24, 30, 51, 61, 93, 95 light cycle, 93, 95 liquid chromatography, ix, 71, 75 localization, ix, 71, 72, 76, 80, 82, 86 Louisiana, 21, 137 lumen, 110 luteinizing hormone, 15 lysosome, 80

M magnitude, 127 majority, 62, 65 Malaysia, 3, 24, 45, 129, 136 mammal, 79, 86 mammals, 3, 73 management, viii, 2, 17, 18, 46 manganese, 102 mangrove forests, 128, 131, 137, 138, 139, 143, 144, 145 mangroves, xi, 110, 123, 124, 126, 127, 128, 131, 133, 134, 135, 137, 138, 144 mapping, ix, 49, 50

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152

Index

marine environment, 108, 136, 140 marketing, viii, 2 marsh, xi, 91, 93, 101, 102, 124, 125, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 140, 141, 142, 143, 145 mass, 24, 64, 67 materials, 77, 125, 127 matrix, 77, 78 matter, 80, 91, 124, 131, 132, 133, 134, 137, 141 Mauritania, 138 Mauritius, 3, 139 meat, 18, 29, 37 media, 111 median, 58, 62 Mediterranean, 29 medulla, ix, 71, 74, 75 medulla treminalia, ix, 71 mercury, 103, 122 metabolism, 76, 80, 83, 120 metals, xi, 92, 93, 101, 102, 107, 108, 109, 110, 111, 117, 119, 121, 122 Mexico, 139, 143, 146 mice, 83 microhabitats, 104 microscope, ix, 71, 72, 84, 117 microscopy, x, 16, 72, 80 microstructures, 75, 122 migration, 67, 78 mineralization, 128, 131, 142 mitochondria, 108, 109, 117, 118, 119 mitochondrial DNA, 21 mitosis, 117 mixing, 33, 67, 141 models, xi, 124 molecular structure, 79 molecular weight, ix, 33, 71, 72, 73, 76, 78, 79, 84 molecules, 108, 109 mollusks, 35 molting stage, viii, 27 monoclonal antibody, 13 morbidity, vii, 1, 5, 6, 14, 18 morphogenesis, 20

morphology, 3, 14, 20, 74, 91, 120, 141, 145 mortality, vii, 1, 4, 5, 6, 7, 8, 9, 10, 11, 13, 14, 18, 22, 24, 101, 139 mortality rate, 11 Mozambique, 141

N Na+, 108, 111, 118, 122 NaCl, 112 negative consequences, 45 negative effects, 43, 140 Netherlands, 138 neuroendocrine cells, ix, 71, 74, 75, 84 neuroendocrine system, 73 neuropeptides, 73 neurosecretory, ix, 71, 74, 84 New England, 136 Newfoundland and Labrador (NL), ix, 49 Nigeria, 139 nitrification, 128 nitrogen, 83, 84, 95, 98, 128, 131, 137, 143, 145 NOAA, 70 nuclear membrane, 81 nuclei, 5, 12 nucleic acid, 12, 17 nucleotides, 33 nucleus, x, 72, 74, 80, 81, 82, 84 nutrient, 100, 128, 131, 139, 144 nutrients, x, 90, 91, 100, 109, 117, 119, 131 nutrition, 79, 100, 141, 142

O obstruction, 40 oceans, 3 octopus, 29, 44 oocyte, 73 operations, 45 optic ganglia, ix, 71, 73, 74, 75, 76, 84 organ, x, 72, 73, 80, 81, 82, 84, 108 organelles, 80, 117, 118, 119

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Index organic matter, 91, 124, 131, 132, 133, 134, 137, 141 organism, viii, 27, 33, 40, 43 organs, 5, 14, 16, 22, 37, 108, 117, 120 overlap, 54, 58, 60, 66, 67, 68 ovum, 83 oxidation, 130 oxygen, 109, 118, 122, 128, 137, 142

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P Pacific, 3, 13, 21, 23, 24, 29, 125, 127, 137, 140 Panama, 129 parallel, 11, 16 pathogenesis, 20, 24 pathogens, 14, 17 pathology, 21 pathways, 111, 128, 130, 142 PCR, 6, 9, 11, 15, 16 permission, iv, 8, 10 personal communication, 100 phagocytosis, 109 phenotypic variations, 19 Philippines, 3, 20, 36, 37, 46 phosphate, 80 phosphorus, 80 phosphorylation, 82 physical characteristics, 52 physical environment, 64 Physiological, 77, 103, 139 physiology, 91, 101 plant growth, 130 plants, 3, 127, 140, 145 plasma membrane, xi, 81, 86, 88, 107, 110, 113, 118 pollutants, 91, 92 polyacrylamide, x, 72, 77, 83 polymerase, 6, 21 polymerase chain reaction, 6, 21 polymorphism, 15 polypeptide, 13 population, 58, 67, 90, 93, 95, 99, 100, 102, 103, 138, 143 population density, 100, 102

portability, 30 Portugal, 126, 139, 146 predation, 44, 51, 100, 101, 103, 105, 131, 136, 139, 141, 142, 144 predators, 91, 100, 101, 102, 138, 144, 145 preparation, x, 19, 72, 87 prevention, 45 principles, 68, 100 probability, 8, 10, 40, 45, 66 proline, 121 protection, 9, 66 proteins, ix, 13, 15, 72, 73, 78, 79, 83, 84, 85, 86, 87, 88, 110, 117, 119 purification, ix, 71, 76, 87, 88

Q quantification, 8, 14, 16 Queensland, 20, 47

R random numbers, 8, 10 reaction rate, 83 reactivity, 13 receptors, 33, 87 recovery, 14 regeneration, 101, 103, 127, 128, 136, 138, 140 reproduction, 72, 83, 87, 88 reproductive organs, 22 requirements, 67 researchers, 74 reservoir hosts, vii, 1, 3 resistance, 3, 8, 17, 24, 105 resources, ix, 28, 43, 44 respiration, 109, 110, 118, 120, 128, 142 response, 24, 92, 136, 145 restriction fragment length polymorphis, 15 reticulum, x, 72, 80, 82, 84 reverse-phase high-performance liquid chromatography (RP-HPLC), ix, 71, 75 ribosomal RNA, 15 risk, 18, 101, 103, 104, 105

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risk management, 18 river systems, 110 RNA, 12, 15, 16, 24 room temperature, 93, 113 root, 104, 128, 130, 133, 139, 142 roughness, 57 routes, vii, 1, 5, 6, 7, 11, 12, 14, 19, 111

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S salinity, 108, 109, 111, 112, 120, 122, 142, 143 Saudi Arabia, 139 scatter, 57, 60 scavengers, 33 Scylla olivacea, vii, 1, 9, 22 Scylla paramamosain, vii, 1, 7, 20, 24 Scylla tranquebarica, vii, 1, 4 SDS-PAGE, ix, 72, 77, 78, 79, 83 secrete, 77 secretion, 76, 109, 110, 117 sediment, xi, 91, 93, 94, 95, 98, 99, 100, 124, 125, 128, 130, 132, 133, 134, 135, 136, 139, 141, 146 sediments, 92, 93, 94, 95, 99, 100, 102, 128, 129, 130, 132, 133, 136, 140, 142, 143 seed, xi, 123, 132, 135, 138, 144 segregation, 60, 67 selectivity, 43, 44, 46 seminal vesicle, 77, 83 sensing, 39 sensitivity, 11, 34 sensors, 33 sequencing, 15 serine, 34 serum, 83, 84 sewage, 92, 110 sexual dimorphism, 52, 145 shape, 12, 13, 39, 41, 74, 76, 80, 83 sheep, 73, 88 shoots, 127 shores, 29 showing, 2, 8, 32, 35, 110

shrimp, 4, 12, 13, 14, 19, 20, 21, 22, 23, 24, 25, 56, 85, 87, 88, 90, 104, 105, 120, 122, 141, 142 signs, 6, 63 Singapore, 4, 126 sinus gland (SG), ix, 71, 74 skin, 33, 37 Snow Crab (Chionoecetes opilio), ix, 50, 52, 68, 69, 70 sodium, x, 72, 118 solution, 112, 113 South Africa, 3, 126, 132, 138, 141 South America, 13, 125 Southeast Asia, 4, 22 Spain, 144 species, vii, ix, xi, 1, 2, 3, 4, 5, 6, 9, 11, 12, 13, 14, 16, 17, 18, 20, 21, 22, 23, 28, 29, 30, 32, 33, 37, 38, 43, 44, 49, 50, 51, 52, 54, 55, 56, 57, 58, 60, 61, 62, 63, 64, 65, 66, 67, 68, 79, 90, 91, 100, 105, 108, 109, 124, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 137, 140, 142, 144 speculation, 142 spending, x, 90 sperm, ix, 72, 73, 77, 78, 79, 80, 82, 83, 84, 85, 86, 87, 88 spermatid, 80, 81, 82 spermatogenesis, 73 stability, 73, 76, 121 stars, 64, 65 state, viii, 27, 120 statistics, 46 sterile, 7, 16 stimulant, 34 stock, 52 stoichiometry, 100, 103 stomach, 6, 7, 11 storage, 74, 77, 87, 109, 117, 119 stress, 45, 100 structure, 20, 69, 73, 79, 80, 81, 82, 83, 86, 103, 109, 120, 122, 146 substrate, viii, ix, 27, 34, 49, 50, 57, 58, 59, 65, 66, 80 substrates, ix, 49, 57, 59, 64, 66, 67 sucrose, xi, 107, 113, 114, 115, 116, 119

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Index sugarcane, viii, 28, 35, 36, 37, 44, 46 Sun, 73, 86, 87, 88, 141 surface area, 109, 128, 130 survival, 8, 9, 10, 11, 14, 29, 101, 145 survival rate, 11, 29 survivors, 95, 99 susceptibility, vii, viii, 2, 5, 6, 7, 9, 11, 13, 15, 18, 22, 23 suspensions, 17 swelling, x, 72, 83, 84 symptoms, 2, 5, 6 syndrome, vii, 1, 2, 13, 19, 20, 21, 22, 23, 24, 25 synergistic effect, 36 synthesis, 73, 109, 122

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T Taiwan, 3, 4, 9, 16, 19, 22, 23, 29, 86, 126, 144 tanks, viii, 28, 93, 95, 112 tannins, 131 Tanzania, 126, 132 target, viii, 5, 27, 28, 29, 30, 32, 40, 41, 42, 43, 44 target organs, 5 Taura syndrome, vii, 1, 2, 13, 19, 21, 22, 23, 24 taxonomy, 20, 22 techniques, 14, 16 technologies, ix, 49, 50 teeth, 3, 4, 55 temperature, viii, x, 27, 52, 57, 58, 60, 61, 62, 65, 66, 67, 72, 83, 84, 86, 93, 113 temporal variation, 126 terminals, ix, 71, 74, 76, 84 testis, 83, 87 Thailand, 1, 3, 4, 12, 20, 21, 22, 130, 133, 145 thermal stability, 73, 76 thorax, 51 threats, vii, 2, 6, 16, 17 tides, 93, 124, 125, 135 tissue, 11, 13, 16, 21, 74, 83, 113, 121 toxic effect, 111

toxic metals, 101, 111 toxicity, 103, 110, 111, 120 transformations, 128 transition metal, 110 transmission, vii, ix, 1, 2, 5, 6, 12, 14, 16, 17, 18, 19, 21, 23, 71 transport, vii, xi, 68, 107, 109, 111, 112, 113, 114, 116, 117, 118, 119, 120, 121, 123, 124, 125, 132, 134, 135, 136, 139 transport processes, 119 treatment, 38, 92 triggers, 45 tropism, 13, 22 trypsin, x, 72, 83, 84 Tuckerton (TK), x, 90, 93 turnover, 133, 141 two sample t-test, 94

U ultrastructure, 19, 22, 81, 120 United Kingdom (UK), 102, 135 United States (USA), 21, 24, 51, 70, 89, 104, 123, 126, 127, 129, 130, 133, 140 Uruguay, 127

V vacuole, 117 valve, 43 variables, 124, 135 variations, vii, 1, 14, 19, 55, 126, 129 vas deferens, 77, 78, 80, 83 vegetation, 124, 135, 137 vein, 130 Venezuela, 126, 143 vertical transmission, 5, 14 vesicle, x, 72, 74, 77, 80, 82, 83, 84 vessels, 57 videotape, 101 Vietnam, 3, 4, 12, 20 viral diseases, vii, 1, 2, 17, 20 viral infection, viii, 2 viral pathogens, 14

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virus infection, vii, 1, 22 viruses, 2, 3, 5, 12, 15, 16, 17, 18, 20, 23, 24 viscera, 33, 37 vision, 91 vitamins, 37

W

Y yellow head disease, vii, 1, 2, 12 Yemen, 3 yolk, 15

Z zinc, 102, 110, 121, 122

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walking, 4, 33, 91, 94, 96, 97 Washington, 70 waste, xi, 107, 142 water, vii, viii, xi, 5, 11, 12, 14, 17, 27, 30, 35, 39, 50, 51, 52, 60, 62, 64, 67, 69, 88, 91, 93, 95, 100, 107, 108, 110, 111, 112, 118, 120, 121, 128, 134, 143 water chemistry, 143 West Africa, 138

wetlands, xi, 123, 124, 139, 143 white spot disease, vii, 1, 2, 4 worldwide, xi, 123, 124, 128 worms, 35

Crabs: Anatomy, Habitat and Ecological Significance : Anatomy, Habitat and Ecological Significance, Nova Science