Fish Parasites

  • Published on
    22-Oct-2014

  • View
    795

  • Download
    0

Embed Size (px)

Transcript

PARASITES OF OFFSHORE BIG GAME FISHES OF PUERTO RICO AND THE WESTERN ATLANTIC

PARASITES OF OFFSHORE BIG GAME FISHES OF PUERTO RICOAND THE WESTERN ATLANTIC

Ernest H. Williams, Jr.and

Lucy Bunkley-Williams

Sportfish Disease Project Department of Marine Sciences and Department of Biology University of Puerto Rico P.O. Box 5000 Mayagez, PR 00681-5000 1996

2Cover drawing: Atlantic blue marlin with magnifications of parasites found on this host in Puerto Rico. Cover by Ms. Gladys Otero

Published cooperatively by the Puerto Rico Department of Natural and Environmental Resources , P.O. Box 5887 , Puerta de Tierra, San Juan, PR 00906; and the University of Puerto Rico, Mayaguez, PR 00681

Funding provided by the Department of Natural and Environmental Resources with Sportfish Restoration Funds, Federal Aid Projects F-28 and F-35 (U.S. Fish and Wildlife Service) and the University of Puerto Rico, Mayaguez.

The content of this book is the sole responsibility of the authors and does not necessarily reflect policy of the Department of Natural and Environmental Resources or the U.S. Fish and Wildlife Service.

Printed by Antillean College Press, Mayaguez, PR 00681 First printing 1.5 M, 1996

Library of Congress Catalog Card Number 96-86468 ISBN 0-9633418-2-0

Any part of this book may be copied for individual use. Whole copies may be requested from: The Department of Natural and Environmental Resources or Ernest H. Williams, Department of Marine Sciences, University of Puerto Rico, P.O. Box 908, Lajas, PR 00667

Suggested citation: Williams, E. H., Jr. and L. Bunkley-Williams 1996. Parasites of offshore big game fishes of Puerto Rico and the western Atlantic. Puerto Rico Department of Natural and Environmental Resources, San Juan, PR, and the University of Puerto Rico, Mayaguez, PR, 382 p., 320 drawings.

Key Words: Fish parasites, big game fishes, parasite ecology, parasite evolution, fish diseases.

3

CONTENTSREVIEWERS ............................................................................................. INTRODUCTION ..................................................................................... Definitions and conventions................................................................. PROTOZOA (PROTOZOANS)................................................................. MYXOZOA (MYXOZOANS) ................................................................... FUNGI (FUNGUS) .................................................................................... PLATYHELMINTHES (FLATWORMS) ................................................ Udonellidea (copepod worm) ............................................................... Digenea (flukes)................................................................................... Didymozoidea (tissue flukes) ......... .................................................... Monogenea (gillworms) ................................. .................................... Cestoda (tapeworms).......................................................................... NEMATODA (ROUNDWORMS)................................ ........................... ACANTHOCEPHALA (SPINY-HEADED WORMS)............................. CRUSTACEA (CRUSTACEANS) ..................... ...................................... Ostracoda (seed shrimp) .............................. ........................................ Copepoda (copepods) .................................. ....................................... Branchiura (fish lice) ...................................... .................................... Cirripedia (barnacles) ............................... .......................................... Isopoda (isopods) ................................................................................. PISCES (FISHES) ..................................................................................... Petromyzontiformes (lampreys) ......................................... Squaliformes (cookiecutter sharks) ....................................................... Perciformes (remoras and pilotfish) .............. ....................................... OTHER DISEASES AND CONDITIONS .............. .................................. DISCUSSION .............................................. .............................................. Harm caused by parasites ........................ ............................................. Transmission of parasites .............................. ...................................... Usefulness of parasites .................................... .................................... HOST SUMMARIES AND HOST-DISEASE CHECKLISTS ................. ACKNOWLEDGMENTS Assistance ................................................ ............................................ Illustration sources .................................. ............................................. BIBLIOGRAPHY ............................................. ......................................... INDEX .................................................................... .................................. ABOUT THE AUTHORS ...................................... .................................. 4 5 7 11 11 19 22 22 24 64 79 103 133 156 163 163 165 223 224 228 239 241 242 247 260 267 267 268 270 275 341 342 344 363 381

5

INTRODUCTIONThe purpose of this book is to serve as a fish parasite guide for sport fishermen, commercial and tour-guide fishermen, fishery biologists, ecologists, scientists, and anyone interested in the health and welfare of big game fishes. We hope it will encourage the study of the interrelationships between fishes and their intimate parasite partners around Puerto Rico and throughout the Atlantic. Big game fishes are important sportfishing and food resources. Many of their fish parasites attract the attention of fishermen because they are large, abundant and always on particular host species. The health of these fishes, and the humans who enjoy catching and eating them, is of great concern. The environments of many coastal areas have deteriorated and there is little agreement about how much of this environmental damage has spilled over into the open ocean. The abundance and diversity of big game fish parasites might be used as an indicator of environmental changes. Many parasites are useful as biological tags for tracing stock movements, mixing, migrations and other aspects of the biology of big game fishes. They can also provide readily available examples of many invertebrate phyla which can be used for classroom examinations. The present knowledge of parasites of big game fishes is at the most basic level, describing species, but the interrelationships between big game fish parasites and their intermediate and final hosts are as complex and intricate as food webs described by ecologists. It is extremely difficult to study the parasites and diseases of live oceanic, fast-moving fishes. Hook and line fishing selects for healthy fishes because sick fishes seldom bite lures or baits. Debilitated fishes in the open sea are quickly eaten, or sink, and seldom wash ashore. Still, we can assume that parasites and diseases cause as many problems for these big game fishes as they do for fishes in more easily examined habitats. A study found that the presence of one species of parasite reduced the yield of a big game fishery by about one fifth. We estimate that somewhere between one third to one half of all big game fish resources are lost due to disease. We need to understand the workings of diseases throughout the ecosystem if we are to have any hope of recuperating losses due to diseases. Unfortunately, we lack complete knowledge of these processes in a single fish, or even of a single disease organism! Most big game fishes are either already overexploited, or are soon to be over fished. As dolphin, greater amberjack and other big game fishes are raised in captivity, we are beginning to discover their deadly parasitic, bacterial and viral diseases. We cannot afford to ignore manageable problems that have the potential to double the stocks of big game fishes We hope that this book will serve as a beginning to better understand these forces in the ecology of big game fishes. No one before has had the opportunity to make an overview of an entire ecological mix of parasites of the dominant predators of an ocean system. We discuss some trends and relationships, but too little information exists for a

6

PARASITES OF OFFSHORE BIG GAME FISHES OF PUERTO RICO complete analysis of this system. Even though many big game fishing tournaments are held every year, there is an incredible lack of published information and basic knowledge about parasites of big game fishes. Much confusion has been caused by the difficulties in identifying these parasites. We hope this book will solve that problem and will allow fisherman and amateur scientists to make contributions to our knowledge of big game fishes. It is a world of great to little mysteries--all worthy of exploration. The information included in this book comes from our long-term, original observations on big game fishes in Puerto Rico, the West Indies, Gulf of Mexico, Atlantic coast of North America, and from published records in a scattered, often obscure and contradictory literature. Fishes examined in this work were collected by hook and line in fishing tournaments in Puerto Rico from 1974 to 1996 and in Dauphin Island, Alabama, from 1967 to 1974; or by individual sport fishermen and scientists (see Acknowledgments). Some of the barracuda, mackerels and jacks were speared by the authors using skin and scuba diving equipment; or collected with nets by Department of Natural and Environmental Resources (DNER) personnel. There was no attempt to make systematic collections. Parasites were either removed from freshly caught hosts and preserved immediately, or organs and tissue samples removed and placed in plastic bags surrounded by ice for laboratory examinations within 24 hours. We recognize 39 species of offshore big game fishes in the western Atlantic. Three (Atlantic bonito, chub mackerel, frigate tuna) have not been reported off Puerto Rico and 3 others only occur further south (serra Spanish mackerel) or north (Atlantic mackerel, Spanish mackerel) than our island. They were included to provide a more complete analysis of these otherwise rather homogenous, and wide-ranging, groups of fishes and parasites. We identify and define 273 species on/in these fishes from the western Atlantic. Each parasite species is illustrated and descriptions of its diagnostic characters, records, geographic range, location in host and length are always presented; and, usually to occasionally, name, life history, ecology, associations, host specificity, damage to host, detection, harm to humans, preparation for study, treatment and significance to sport fishing are discussed. The damage parasites cause in big game fishes has rarely been documented histologically (in tissue sections), therefore we have estimated potential damage based on number and size of parasites, known pathological changes caused by similar infections, and our own experience. No genius is required to predict that superinfections will harm a host, but our other interpretations may be less certain. Most families and genera of parasites are not discussed as groups except for a few that have a series of similar species. In these cases it was more efficient to discuss their similar characters rather than repeating this information with every species. Methods are suggested to avoid the spread of diseases. Diseases of big game fishes (other than parasites) are noted. The importance of parasites, their use as environmental indicators, controlling and avoiding fish parasites and the effects of fish parasites on humans are discussed. Damaging and dangerousparasites are described, and methods to protect human health are explained. The

INTRODUCTION

7

Host Summaries and Host-Disease Checklists include the complete classification of

these fishes and a list of the diseases we found on each host from the western Atlantic and parasites on these fishes worldwide. We hope you will use this book as your guide to the parasites of big game fishes. Within the drama of big game fishing lies a play-within-a-play of the parasites and associates of these great fishes. We look forward to receiving reader input concerning these fascinating creatures. - - - Good fishing!

DEFINITIONS AND CONVENTIONSWe tried to avoid the use of scientific jargon, but some scientific terms must be used for the sake of conciseness, clarity or continuity. These terms are either defined where they appear, in each section explanation or below. Levels of Infection Levels of infections for microscopic parasites (protista) were estimated from very light =