Biology and Exploitation J.V. HUNER J.E. BARR f !!;!!$-'$! 0jtiy$~l'tI! !! /gky1yi//j!i' !V5%! LOUISIANA SEA GRANT COLLEGE PROGRAM ACKNOWLEDGMENTS Illustrations are courtesy of Carolina Biological Supply,H. H. Hobbs,Jr., B. Huner, K. Lyle, W. Hayes III, the Louisiana Agricultural Experi- ment Station, J. Witzig, S. K. Johnson, D, IGarberg, G. Warren, and the U.S. Soil Conser- vation Service. The crawfish depicted in Figures 4, 5, 6 and 22 are taken from the original print of the red crawfish in Huxley's 1868 publication, The Crayfish. It was the only cambarid crawfish illustrated in that work, This book was published by the Louisiana Sea Grant CollegeProgram, a part of the National Sea Grant CollegeProgram inaintained by the National Oceanic and Atmospheric Adminis- tration, U.S. Department of Commerce,and supported by the state of Louisiana. Third Edition, January 1991 Edited by Elizabeth B. Coleman Designedby Ken Varden Layout by Bonnie Grayson Q The Louisiana Sea Grant College Program Center for Wetland Resources Louisiana State University Baton Rouge, Louisiana 70803-7507 FOREwORD This is the third edition of Red Swamp Crawfish: Biology and Exploitation. Since 1980, when this book was first written, crawfish cul- ture has expanded greatly, and there is now a pioliferation of research data where previously only educated guesses were available, especially in regard to exploitation. The white river crawfish frequently appears with the red swamp crawfish and we have ex- panded our discussion of this species. It must be noted, however, that the taxonoiny of this species has changed. Dr. Horton H, Hobbs, Jr., the nation's foremost crawfish identification special- ist taxonomist! has divided the species formerly called Procambarus acutus acutus into three separate species, The one most commonly en- countered in the eastern U.S. is Procambarus acutus acutus. The common species in Louisiana and Texas crawfish ponds and natural habitats is Procambarus zonangulus, The species that occurs throughout the rest of the central U.S. has yet to be named. Unless otherwise noted, any reference to white river crawfish is a reference to Procambarus zonangulus, not Procambarus acutus acutus or the unnamed species. The majority of this book is still devoted to the management and culture of the red swamp crawfish, Procambarus clarkii, the most cosino- politan of the crawfish species. The text is not intended to be an all-encompassing technical treatment of crawfish biology and exploitation, but a practical guide for the crawfish culturist, For those interested in further, more technical, information, an excellent scientific text on the subject is Freshwater Crayfish. Biology, Manage- ment, and Exploi tation, edited by D. M. Holdich and R. S. I owery and published in 1988 by Croom Helm London and Sydney! and Timber Press Portland, Oregon!. We hope that this book will provide new and useful information. We welcome comments from readers for future editions. J. H. Huner Department of Agricultural Sciences, Technology, and Education University of Southwestern Louisiana Lafayette, Louisiana 70504 CONTENTS INTRODUCTION SOCIAL IMPORTANCE OF CRAWFISH .... ....52 GENERALBIOLOGY CULTURAL IMPACT . 52 ECONOMIC PROBLEMS EXTERNAL ANATOMY ...... 4 Appendages .4 EXPLOITATION . 55 Exoskeleton .6 PRODUCTION: WILD/DOMESTIC ............. , 56 Physical Variations .8 Harvesting 56 INTERNAL ANATOMY .8 Tray Designs 57 Digestive System Trap Density 59 Muscular System . .89 9 Trapping in Natural Waters ...........,....... 60 Respiratory System Bait.......................,........,...,..., .. 60 Circulatory System 11 Baitless Traps. 61 Nervous System . 11 Factors Affecting Crawfish Catch ................ 62 Endocrine System . 14 Harvesting Methods in Natural Watei's ....62 Behavior . 15 Harvesting Methods in Ponds ...................... 62 Reproduction System 20 Trap Mechanization 65 Development and Growth 21 Seine and Trawl Systems,...,........................ 65 Excretory System . 25 Handling Crawfish . 65 Molting in Crawfish, .26 Holding Crawfish 65 DISEASES 29 Shipping and Storing Live Crawfish.......... 66 Grading . 68 SPECIFIC DISEASES .29 Crawfish Products 68 Microbial Diseases 29 Processing . 68 Protozoan Diseases .29 Marketing, 71 Internal Worms, .30 Legal Considerations . 72 EXTERNAL INVERTEBRATES ...,... ..... 3 1 Catching Ciawfish For Fun ......,....,.......,., 72 Branchiobdellid Worms .31 FISHERIES MANAGEMENT .... ,................. 72 Microcrustaceans ...31 Atchafalaya Basin Studies......................., 73 Nematodes .31 Population Estimation 73 CONDITIONS. .....31 Population Condition 74 Water Boatman Eggs .31 Tumors, .32 CULTURE . 74 .32 Uropod Swellings BRIEF HISTORY OF RED CRAWFISH Gas Bubble Disease 32 CULTURE. 75 Soft-Shell Syndrome . .32 LEGAL ASPECTS OF CRAWFISH Hollow- Tail Syndrome, 32 FARMING 75 RESISTANCE TO AND CONTROL 0 F CRAWFISH CULTURE 75 DISEASES .32 ECONOMICS 76 TAXONOMY AND ZOOGEOGRAPHY .... ................. 33 PONDS . 77 NOMENCLATURE.. 33 Types 77 CLASSIFICATION OF CRAWFISH ................... 33 Site Selection 78 ZOOGEOGRAPHY, . 37 Construction . 78 WATER MANAGEMENT . 79 DISTRIBUTION OF P. CLARXEI ....... .....,... ... 38 Control 79 ECOLOGY . .39 Flooding . 79 ENERGY FLOW .40 Draining. 80 TROPHIC RELATIONSHIPS ............. .....,...40 Water Quality 80 INVERTEBRATE PREDATORS ..,. ....,.......... 4 1 Turbid Water . 81 VERTEBRATE PREDATORS ............ ......,.... .. 4 1 Sources of Water . 82 CRAWFISH ASSOCIATES 42 Pesticides 82 Red Swamp and White River Cra wfish ........ 42 Crawfish Control Toxicants,...,............... 83 83 BURROWS. .,44 NUISANCE ANIMALS 83 HABITATS 47 SUBSTRATE. WATER QUALITY 50 FEED AND FERTILIZERS 85 THE FLUSHING ACTION OF FLOO DING Natural Feeds and Crop Rotation ................ 85 RIVERS ..51 Natural Vegetation 85 DISPERSAL. .52 Agricultural Wastes .. 86 Planted Forage Crops ....86 OFF-SEASON CRAWFISH PRODUCTION Artificial Feeds . .88 IN THE SOUTH 106 Use of Fertilizers . ....89 PRODUCTION OF CRAWFISH FOR POND CRAWFISH POPULATION FISH BAIT 107 DYNAMICS ....89 Products 108 Stocking.......,.....,............. ..90 Harvesting 109 Care of Brood Crawfish ....91 Handling and Shipping of Bait Crawfish .. 110 Burro wing Activity, ....91 SOFT-SHELLED CRAWFISH ............. .... 110 Growth and Mortality 92 OTHER SPECIES OF AMERICAN Movements In and Around Ponds ... ...,96 CRAWFISH SUITABLE FOR Yield ....96 CULTIVATION 111 Stunting . ,....,............ ....97 Monitoring Ponds and Predicting Yields .....98 AUSTRALIAN CRAWFISH .... 112 Collection of Crawfish 98 CRAWFISH ASSOCIATIONS ... .... 112 Crawfish and Waterfowl Management ...... 102 LIST OF FIGURES .. 113 POLYCULTURE: CRAWFISH AND FISH ..... 103 LIST OF TABLES .. 114 ARTIFICIAL SPAWNING OF RED CRAWFISH . 104 APPENDIX A ...,....,....., .... 115 Black Method .... 104 APPENDIX B ....116 Wright Method ,. 105 Gooch Method . .... 105 APPENDIX C ..... 118 Off-Season Production and Other APPENDIX D Species . .... 106 ..... 119 GENETICS .... 106 APPENDIX E .121 MANAGEMENT PROCEDURES IN LOUISIANA AND ELSEWHERE ....... ... 106 BIBLIOGRAPHY . .122 IN:,. DUCTION Freshwater crawfish have had a close associa- tion with western man for centuries. Huxley's magnificent 1868 work entitled The Crayfish as- sured that virtually every high school and college biology student would study these small decapod crustaceans as part of a comprehensive education. The didactic value of these creatures is difficult to question, and physiologists, ecologists, ethologists, and inany other natural scientists have found them ta be excellent subjects for their studies, Crawfish have played a major role in the history af western man. For centuries they have been an important food resource in Europe, as- suming a unique cultural role. Their value has been greatly magnified in recent decades when habitat destruction and the crawfish plague reduced supplies and restricted access to the catch from the general public. When Europeans came to North Ainerica, they found vast numbers of crawfish in the lower Mississippi River Valley, the Great Lakes region, and the West Coast. These had lang been exploited by the Indians. The Swedes and Fi enchmen, who had come from regions of Europe where crawfish were highly prized, quickly took advantage of the newfound bonanza. Over the years, food fisheries have developed into a successful business with up to 100,000,000 lbs of crawfish harvested annually. However, most of this activity has been centered in Louisiana where the unique topography of the land results in huge overflaw swamps. These are formed by the flooding Mississippi River as it reaches the Gulf af Mexico fram the continent's heartland. Such swamps provide virtually unlimited habitats for Fig. 1. Adult male red crawfish. crawfish. The West Coast catch approaches 1,000,000 lbs per year, but the resaurce is largely Over 100,000,000 pounds of red crawfish are underexploited. Most production is shipped ta harvested annually in the U.S. from swamps, Europe whei e native species have been decimated marshes, and cultivated ponds, with 80-90 percent by pollution and disease. Production in the Great coming from Louisiana. The red crawfish is native Lakes area exceeds 200,000 lbs per year. ta northern Mexico and the Mississippi Valley as In North America, crawfish are most com- far north as southern Illinois. It has been success- monly used for fish bait, Their unique trophic fully introduced on both the east and west coasts of status as detritivores establishes them as impor- the U.S. A hardy, adaptable species,