Đang tải... (xem toàn văn)
Demand for the German editions and for the English translation of this book on eels has made it necessary to publish a further English edition. It is based on the third German edition (1999) and contains further updatings. The unusually high demand for a book specialising on a single genus is due to the eel’s scientific and gastronomic popularity in large areas of Europe and in Japan, and the scientific demand has expanded greatly since first publication of the book in 1973, especially in East Asia and Australia/New Zealand. Subject areas like continental ecology and aquaculture contributed to this. These have drawn in with them other topics like oceanic ecology, genetics, and parasitology: this edition contains a completely new section for genetics. With regard to the oceans, meteorology and sea currents expanded interest in eels to specialists of those subjects. In the 1970s, the author was even asked whether knowledge of eel occurrence in the various parts of the oceans could also contribute to exploration of ocean currents. In North America, until then interest in eels was limited to the areas of its continental occurrence along the east coast. Besides the economics of the eel, its importance as an oceanographic indicator has expanded interest in this animal among other circles, especially in North America and East Asia Accordingly, it seemed appropriate to consult with other colleagues in certain subject areas of this book, so specialists in endocrinology, genetics, aquaculture, parasitology and toxicology, among others, were brought in. The descriptions of fishing techniques also benefited from collaboration of a specialist. It became clear that almost no other fish species is caught by such a diverse range of gear, so this chapter represents almost a crosssection of general fish catching technology. Recent population decline of some eel species created utmost economic and scientific interest. This might be equated with the diminution of other economically important food fishes and blamed on overfishing. But because the critical times of the eel’s highest mortality extend over longer periods than those of other fishes, and are primarily at sea, this decline cannot be explained so simply. Therefore, in the present English edition the marine phases receive no less attention than do the continental phases of the life cycle. The data on the marine biology of the eel are increasingly important also because there are considerable deficiencies in knowledge of the Indopacific species relative to the Atlantic species, even though in recent years research activities on eels in the Pacific Ocean have far exceeded those in the Atlantic. Sincere thanks are due to the Fisheries Society of the British Isles whose generous financial support enabled the translation of this book to go ahead. Finally, I must express my grateful thanks to all those who have helped in the production of this book. I feel particularly indebted to the translator, the editor and the publisher, who have worked so conscientiously to ensure the appearance of the second English edition.
The Eel Third edition F.-W Tesch With contributions from P Bartsch, R Berg, O Gabriel, I.W Henderson, A Kamstra, M Kloppmann, L.W Reimer, K Söffker and T Wirth Translated from the German by R.J White Edited by J.E Thorpe The Eel The Eel Third edition F.-W Tesch With contributions from P Bartsch, R Berg, O Gabriel, I.W Henderson, A Kamstra, M Kloppmann, L.W Reimer, K Söffker and T Wirth Translated from the German by R.J White Edited by J.E Thorpe © 2003 Blackwell Science Ltd, a Blackwell Publishing Company Editorial Offices: Blackwell Publishing Ltd, 9600 Garsington Road, Oxford OX4 2DQ, UK Tel: +44 (0)1865 776868 Iowa State Press, a Blackwell Publishing Company, 2121 State Avenue, Ames, Iowa 50014-8300, USA Tel: +1 515 292 0140 Blackwell Publishing Asia, 550 Swanston Street, Carlton, Victoria 3053, Australia Tel: +61 (0)3 8359 1011 The right of the Author to be identified as the Author of this Work has been asserted in accordance with the Copyright, Designs and Patents Act 1988 All rights reserved No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, except as permitted by the UK Copyright, Designs and Patents Act 1988, without the prior permission of the publisher Title of the original German edition: Tesch, Der Aal, 3., neubearbeite Auflage © 1999 by Parey Buchverlag im Blackwell Wissenschafts-Verlag GmbH, Berlin English edition © 2003 Blackwell Science Ltd, a Blackwell Publishing Company Library of Congress Cataloging-in-Publication Data Tesch, Friedrich-Wilhelm [Aal English] The eel / Friedrich-Wilhelm Tesch ; translated from the German by R.J.White ; edited by John E Thorpe. 3rd ed p cm Includes bibliographical references and index ISBN 0-632-06389-0 (alk paper) Anguilla (Fish) Eel fisheries I Thorpe, J E (John E.) II Title QL638.A55T4713 2003 597′.432 dc21 2003008640 ISBN 0-632-06389-0 A catalogue record for this title is available from the British Library Set in Times and produced by Gray Publishing, Tunbridge Wells, Kent Printed and bound in the UK using acid-free paper by MPG Books, Bodmin, Cornwall For further information on Blackwell Publishing, visit our website: www.blackwellpublishing.com Contents List of contributors vi Preface vii Chapter Body structure and functions Chapter Developmental stages and distribution of the eel species 73 Chapter Post-larval ecology and behaviour 119 Chapter Harvest and environmental relationships 213 Chapter Fishing methods 243 Chapter Eel culture 295 Chapter Diseases, parasites, and bodily damage 307 Chapter World trade and processing 331 References 341 Index 399 Contributors F.-W Tesch Gartenstrasse 1a, 22869 Schenefeld, Germany P Bartsch Naturhistorisches Forschungsinstitut Museum für Naturkunde, Invalidenstrasse 43, 10115 Berlin, Germany (Chapter 1.2) R Berg Fischereiforschungsstelle des Landes Bad-Württemberg, Mühlesch 13, 88065 Langenargen, Germany (Chapter 7.4.4) O Gabriel (deceased) Bundesforschungsanstalt für Fischerei Institut für Fischeretechnik, Palmaille 9, 22767 Hamburg, Germany (Chapter 5) I.W Henderson University of Sheffield, Animal and Plant Sciences, Alfred Denny Building, Western Bank, Sheffield S10 2TN, England (Chapter 1.8) A Kamstra Netherlands Institute for Fisheries Research, Haringkade 1, PO Box 68, NL-1970 AB IJmuiden, The Netherlands (Chapter 6) M Kloppmann Heidblick 23, 21149 Hamburg, Germany (Chapter 1) L.W Reimer Am Bahnhof Mindenstadt 4, 32423 Minden, Germany (Chapter 7) K Söffker Heinrich Lehmann Strasse 2, 31542 Bad Nenndorf, Germany (Chapter 7.4.5) T Wendt Ernst-Mittelbach-Steig, D-22455 Hamburg, Germany (Chapter 5) T Wirth Max-Planck Institut für Infektionsbiologie, Schumannstrasse 21/22, 10117 Berlin, Germany (Chapter 2.5) R.J White 320 12th Avenue North, Edmonds, Washington 98020, USA J.E Thorpe Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, Scotland Preface Demand for the German editions and for the English translation of this book on eels has made it necessary to publish a further English edition It is based on the third German edition (1999) and contains further updatings The unusually high demand for a book specialising on a single genus is due to the eel’s scientific and gastronomic popularity in large areas of Europe and in Japan, and the scientific demand has expanded greatly since first publication of the book in 1973, especially in East Asia and Australia/New Zealand Subject areas like continental ecology and aquaculture contributed to this These have drawn in with them other topics like oceanic ecology, genetics, and parasitology: this edition contains a completely new section for genetics With regard to the oceans, meteorology and sea currents expanded interest in eels to specialists of those subjects In the 1970s, the author was even asked whether knowledge of eel occurrence in the various parts of the oceans could also contribute to exploration of ocean currents In North America, until then interest in eels was limited to the areas of its continental occurrence along the east coast Besides the economics of the eel, its importance as an oceanographic indicator has expanded interest in this animal among other circles, especially in North America and East Asia Accordingly, it seemed appropriate to consult with other colleagues in certain subject areas of this book, so specialists in endocrinology, genetics, aquaculture, parasitology and toxicology, among others, were brought in The descriptions of fishing techniques also benefited from collaboration of a specialist It became clear that almost no other fish species is caught by such a diverse range of gear, so this chapter represents almost a crosssection of general fish catching technology Recent population decline of some eel species created utmost economic and scientific interest This might be equated with the diminution of other economically important food fishes and blamed on overfishing But because the critical times of the eel’s highest mortality extend over longer periods than those of other fishes, and are primarily at sea, this decline cannot be explained so simply Therefore, in the present English edition the marine phases receive no less attention than the continental phases of the life cycle The data on the marine biology of the eel are increasingly important also because there are considerable deficiencies in knowledge of the Indopacific species relative to the Atlantic species, even though in recent years research activities on eels in the Pacific Ocean have far exceeded those in the Atlantic Sincere thanks are due to the Fisheries Society of the British Isles whose generous financial support enabled the translation of this book to go ahead Finally, I must express my grateful thanks to all those who have helped in the production of this book I feel particularly indebted to the translator, the editor and the publisher, who have worked so conscientiously to ensure the appearance of the second English edition 394 References Utida, S., Hirano, T (1973): Effects of changes in environmental salinity on salt and water movement in the intestine and gills of the eel, Anguilla japonica In Chavin, W (ed.): Responses of fish to environmental changes 240–269 Proceedings of a US-Japan seminar held in Tokyo (Japan), 23–26 Nov 1970 C C Thomas (Publisher), Springfield, Illinois (USA) Utida, S., Hirano, T., Kamiya, M (1969): Seasonal variations in the adjustive responses to seawater in the intestine and gills of the Japanese cultured eel, Anguilla japonica Proc Japan Acad 45, 293–297 Utida, S., Hirano, T., Oide, H., Ando, M., Johnson, D W., Bern, H A (1972): Hormonal control of the intestine and urinary bladder in teleost osmoregulation Gen Comp Endocr Suppl 3, 317–327 Utida, S., Isono, N (1967): Alkaline phosphatase activity in intestinal mucosa of the eel adapted to fresh or sea water Proc Japan Acad 43, 789–792 Utida, S., Isono, N., Hirano, T (1967): Water movement in isolated intestine of the eel adapted to fresh water or sea water Zool Mag Tokyo, 6, 128–129 Utida, S., Kamiya, M., Shirai, N (1971): Relationship between the activity of Na+K+-activated adenosinetriphosphatase and the number of chloride cells in eel gills with special reference to sea water adaptation Comp Biochem Physiol 38A, 443–447 Utrecht, W L van, Holleboom, M.A (1985): Notes on eel larvae (Anguilla anguilla Linnaeus 1758) from the central and eastern North Atlantic and on glass eels from the European continental shelf Bijdragen tot de Dierkunde 55(2), 249–262 Vaillant, L (1896): Sur la présence de l’anguille commune en haute mer C r hebd Séanc Acad Sci., Paris 126, 1429–1430 Van der Oost, R., Heida, H., Opperhuizen, A., Vermeulen, N P E (1991): Bioaccumulation of organic micropollutants in different aquatic organisms: sublethal toxic effects on fish In: Mayes, M A., Barron, M G (eds): Aquatic toxicology and risk assessment 14, 166–180 American Society for Testing and Materials, Philadelphia, Van der Oost, R., Opperhuizen, A., Satumalay, K., Heida, H., Vermeulen, N P E (1996): Biomonitoring aquatic pollution with feral eel (Anguilla anguilla) Bioaccumulation: biota-sediment ratios of PCBs, OCPs, PCDDs and PCDFs Aquat Toxicol 35, 21–46 Van Rijsingen, J (1995): European Aquaculture Production Trends & Outlook: Eel Eurofish Report trade Conference 15–16 November 1995, Brussels Veen, T van, Andersson, M (1982): Threshold for synchronization of locomotor activity to visible radiation in the eel Anguilla anguilla Oikos 38, 21–26 Veen, T van, Hartwig, H G., Müller, K (1976): Light dependent motor activity and photonegative behavior in the eel (Anguilla anguilla L.), evidence for extraretinal and extrapineal photoreception J comp Physiol 111, 209–219 Vigh-Teichmann, I., Korf, H.W., Nurnberger, F., Oksche, A., Olsson, R (1983): Opsin-immunoreactive outer segments in the pineal and parapineal organs of the lamprey (Lampetra fluviatilis), the eel (Anguilla anguilla) and the rainbow trout (Salmo gairdneri) Cell Tiss.Res 230, 289–307 Villani, P., Lumare, F (1975): Nota sull’accrescimento ovarico indotta in Anguilla anguilla (L.) Investigacion pesq 39, 187–197 Vilter, V (1942): Régulation sympathico-hypophysaire de migration pigmentaires dans le rétine de l’anguille (Anguilla vulgaris L.) Arch Physiol biol.16 (suppl.), 6–8 Vilter, V (1943): Métamorphose des larves d’anguille dans ses rapports avec l’activité hypophysaire C r Séanc Soc Biol 137, 534–535 Vilter, V (1945a): Développment du tractus gastro-intestinal au cours de la métamorphose de larve d’anguille (civelles) C.r Séanc Soc Biol 139, 223–224 Vilter, V (1945b): Inhibition experimentale de la croissance stomacale au cours de la métamorphose larvaire de l’anguille C r Séanc Soc Biol 139, 817–818 Vilter, V (1946): Determinisme, hypophysaire du comportement “halophobe” de civelles immigrantes C r Séanc Soc Biol 140, 483–484 Vilter, V (1951): Intervention probable de la lumière chez la naissance des structures rétiniennes révelée par l’étude comparée de la rétine chez les anguilles normales et cavernicoles C r Séanc Soc Biol 145 Virchov, H (1882): Über die Glaskưrper und Netzhautgefäße des Aales Morph Jb 7, 573–590 Visurgis (1954): Geräucherter Aal Allg FischZtg 79, 384–385 References 395 Vivien, L (1958): Les glandes endocrines In Grassé, P.P (ed.): Traitée de Zoologie 13/2, 1470–1544 Paris, Masson & Cie Vladykov, V D (1964): Quest for the true breeding area of the American eel (Anguilla rostrata Le Sueur) J Fish Res Bd Can 21, 1523–1530 Vladykov, V D (1966): Remarks on the American eel (Anguilla rostrata Le Sueur) Sizes of elvers entering streams, the relative abundance of adult males and females, and present economic importance of eels in North America Verh Int Verein theor angew Limnol 16, 1007–1017 Vladykov, V D (1971): Homing of the American eel Anguilla rostrata, as evidenced by returns of transplanted tagged eels in New Brunswick Can Fd Nat 85(3), 241–248 Vladykov, V D (1973): Macrophthalmia in the American eel (Anguilla rostrata) J Fish Res Bd Can 30, 689–693 Volf, F., Smí ˘sek, J (1955): Aale in tschechoslowakischen Gewässern Sb C.S Akad zemed Ved 28, 395–410 Vøllestad, L A (1992): Geographic variation in age and length at metamorphosis of maturing European eel: environmental effects and phenotypic plasticity J anim Ecol 61, 41–48 Vøllestad, L A., Jonsson, B., Hvidsten, N A., Næsje, T F., Haraldstad, Ø., Ruud-Hansen, J (1986): Environmental factors regulating the seaward migration of European silver eels (Anguilla anguilla) Can J Fish Aquat Sci 43, 1909–1916 Vøllestad, L A., Lecomte-Finiger, R., Steinmetz, B (1988): Age determination of Anguilla anguilla (L.) and related species EIFAC(FAO) Occasional Paper No 21 Wald, G (1958): The significance of vertebrate metamorphosis Science, 128, 1481–1490 Walter, E (1910): Der Flußaal, eine biologische und fischwirtschaftliche Monographie Verlag J Neumann, Neudamm 346pp Watson, R A (1984): The life cycle and morphology of Tetracerasta blepta gen et sp nov., and Stegodexamene callista sp nov (Trematoda: Lepocreadiidae) from the long-finned eel, Anguilla reinhardti Steindachner Aust J Zool 32, 177–204 Watts, S L., Watts, D C (1974): Nitrogen metabolism in fishes In Florkin, M., Scheer, B T (eds): Chemical Zoology 8, 369–446, Academic Press, New York, London Weber, M (1986): Fishing method and seasonal occurrence of glass eels (Anguilla anguilla L.) in the Rio Minho, West coast of the Iberian Peninsula Vie Milieu 36, 243–350 Wegner, G (1982): Main hydrographic features of the Sargasso sea in spring 1979 Helgoländer Meeresunters 35, 385–400 Wegrzynowicz, R., Zbanyszek, R., Klyszejko, B., Glebocka, G (1979): Effect of crude oil on tissue respiration of eel, Anguilla anguilla (L.) kept in water at 18 °C and 24 °C Acta Ichthyol Piscatoria 9, 31–35 Wehrmann, L (1968): Messungen der Bewegungsaktivität des Aales (Anguilla anguilla L.) unter Verwendung einer Markierung mit Magnetmarken Diplomarbeit Math.-Nat.-Fakultät Univ Hamburg Weiss, A (1995): Aalangeln, fein fängt besser Fisch und Fang 8, 32–53 Wenner, C A (1973): Occurrence of American eels, Anguilla rostrata, in waters overlying the eastern North American continental shelf J Fish Res Bd Can 30, 1752–1755 Wenner, C A., Musick, J A (1974): Fecundity and gonad observations of the American eel, Anguilla rostrata, migrating from Chesapeake Bay, Virginia J Fish Res Bd Can 31, 1387–1391 Wenner, C A., Musick, J A (1975): Food habits and seasonal abundance of the American eel, Anguilla rostrata, from the lower Chesapeake Bay Chesapeake Sci 16, 62–66 Westenburg, J (1952): Acoustical aspects of some Indonesian fishes J Cons perm int Explor Mer 18, 311–325 Westerberg, H (1975): Counter current orientation in the migration of the European eel (Anguilla anguilla L.) Göteborgs Univ Oceanogr Inst Rep., 9, 1–18 Westerberg, H (1979): Counter current orientation in the migration of the European eel (Anguilla anguilla L.) Rapp p.-v Réun Cons int Explor Mer 175, 134–143 White, E M., Knights, B (1994): Factors affecting the upstream migration of elvers and juvenile eels, Anguilla anguilla L., in the Rivers Severn and Avon, England SEI (ICES) EIFAC (FAO) W P on Eel, Oviedo 1994, (Ecol Freshw Fish) Whitefield, R E., Kolenosky, P (1978): Prototype eel ladder in the St Lawrence River Prog Fish Cultur 40, 152–154 396 References Whitehouse, R H (1910): The caudal fin of Teleostomi Proc Zool Soc., London 2, 590–627 Wiberg, U (1983): Sex determination in the European eel (Anguilla anguilla L.) A hypothesis based on cytogenetic results correlated with the finding of skewed sex ratios in eel culture ponds Cytogen Cell Genetics 36, 589–598 Wickins, J F (1987): Effects of size, culling and social history on growth of cultured elvers, Anguilla anguilla (L) J Fish Biol 31, 71–82 Wickström, H., Hamrin, S (1997): Sweden In Moriarty, C., Dekker, W (eds): Management of the European Eel Fish Bull 15, 46–52 Wickström, H., Westin, L., Clevestam, P (1996): The biological and economical yield from a longterm eel stocking experiment Ecol Freshw Fish 5, 140–147 Wiehr, H (1932): Über die Chemie und Biologie der Fettsubstanzen vom Aal (Anguilla vulgaris) Z Fisch 30, 169–196 Wiehr, H (1967): Beschaffung von Aalbrut und Satzaalen in der Bundesrepublik Arch FischWiss 18 (Suppl 1), 467–473 Wierzbicka, J (1986): Sphaerospora sphaerocapsularae sp n (Myxospora, Bivalvulida) a parasite of eel, Anguilla anguilla (L.) Acta protozool 25, 355–358 Wiesner, E (1966): Die Aalwirtschaft des Landes Bayern Regierungsbezirk Schwaben Arch FischWiss., 16 (Suppl 1), 114–130 Wilke, H (1975): Aalaufstieg – leicht gemacht Fisch u Fang 16, 160–161 Willemse, J J (1975): Some remarks on the structure and function of the musculus lateralis in the European eel, Anguilla anguilla (L.) (Pisces, Teleostei) Z Morph Tiere 81, 195–208 Willemse, J J (1979): Guide to the internal morphology of the European eel, Anguilla anguilla (L.) (Pisces, Teleostei) Aquaculture 17, 91–103 Willemse, J J., Ruiter, A de (1979): A quantitative identification of four types of fibres in lateral musculature of immature European eel, Anguilla anguilla (L.) (Pisces, Teleostei) Aquaculture 17, 105–111 Willemse, J.J., van den Berg, P G (1978): Growth of striated muscle fibres in the m lateralis of the European eel, Anguilla anguilla (L.) (Pisces, Teleostei) J Anat 125, 447–460 Williams, G C., Koehn, R K., Mitton, J B (1973): Genetic differentiation without isolation in the American eel, Anguilla rostrata Evolution 27, 192–204 Williamson, G R., Castle, P H I (1975): Large–eyed specimen of eel Anguilla bicolor from a freshwater well Copeia 1975, 561–564 Wiltschko, W., Wiltschko, R (1996): Magnetic orientation in birds J exp Biol 199, 129–138 Winn, H E., Richkus, W A., Winn, L K (1975): Sexual dimorphism and natural movements of the American eel (Anguilla rostrata) in Rhode Island streams and estuaries Helgoländer wiss Meeresunters 27, 156–166 Wippelhauser, G S., McCleave, J D (1987): Precision of behaviour of migrating juvenile American eels (Anguilla rostrata) utilizing selective idal stream transport J Cons Explor Mer 44, 80–89 Wippelhauser, G.S., McCleave, J.D (1988): Rhythmic activity of migrating juvenile American eels Anguilla rostrata J mar biol Ass UK 68, 81–91 Wirth, T., Bernatchez, L., (2001): Genetic evidence against panmixia in the European eel Nature 409, 1037–1041 Woest, O (1977): Entwicklung der Aalzeese Z Binnenfisch 24, 106–111 Wolf, K (1984): Agents: Virales In: Kinne, O (Ed.): Diseases of marine animals Vol IV, Part 1, 17–47 Wolff, B (1912): Über ein Blastom bei einem Aal, nebst Bemerkungen zur vergleichenden Pathologie der Geschwülste Virchows Arch pathol Anat Physiol 210, 369–385 Woods, C S (1964): Fisheries aspects of the Tongariro power project Fish tech Rep N Z., 10, 1–213 Wunder, W (1936): Physiologie der Süßwasserfische Mitteleuropas In: Handbuch Binnenfisch Mitteleur 2B Wunder, W (1963, 1964): Körpergestalt und Lebensweise der Fische Allg Fischztg 88, 22; 89, 1–4 Wunder, W (1967): Die Abschnürung des Magens und seine Umbildung zu einer mit Flüssigkeit gefüllten Blase (Zyste) beim Aal (Anguilla anguilla) Allg FischZtg 92(22) Wunder, W (1968): Hochrückigkeit beim Aal (Anguilla anguilla L.) bedingt durch Wirbelsäulenverkürzung Biol Zbl 87, 325–331 References 397 Wunder, W (1969): Wirbelanalyse mit Hilfe von Röntgenstrahlen bei einem Aal (Anguilla anguilla L.) mit Wellenkrümmung der Wirbelsäule (Plekospondylie) Biol Zbl 88, 611–627 Wundsch, H H (1916): Neue Beiträge zu der Frage nach dem Alter und Wachstum des Aales Z Fisch 18, 55–88 Wundsch, H H (1953): Das Vorkommen von Aalen in “vorgeschrittenem Reifezustand” in einem märkischen Binnengewässer Z Fisch 2, 1–18 Wundsch, H H (1954): Über Alter und Geschlechtsverhältnis bei dem zur Zeit im Handel befindlichen Satzaalmaterial Dt FischZtg Radebeul 1, 9–15 Wurtz-Arlet, J (1961): Verteilung und Ausnutzung der Aalbrut und der Speiseaale in Frankreich Z Fisch 10, 671–675 Yamada, K., Yokote, M (1975): Morphochemical analysis of mucosubstances in some epithelial tissues of the eel (Anguilla japonica) Histochem 43, 161–172 Yamada, Y., Hama, K (1972): Fine structure of the lateral-line organe of the common eel, Anguilla japonica Z Zellforsch 124, 454–464 Yamada, Y., Zhano, H., Okamura, A., Tanaka, S., Horie, N., Mikawa, N., Utoh, T., Okah, H.P (2001): Morphological and histological changes in the swim bladder during maturation of the Japanese eel J Fish Biol 58, 804–814 Yamagata, Y., Niwa, M (1979): The toxicity of nitrite to eel The Aquiculture 27(1): 5–11 Yamagata, Y., Niwa, M (1982): Acute and chronic toxicity of ammonia to eel Anguilla japonica Bull Jap Soc Sci Fish 48(2), 171–176 Yamagishi, I., Nagumo, N., Oshiro, S., Suzuki, S., Takashi, O., Muraki, T (1969): Electron microscopic observations on the absorptive epithelium of eel intestine J Med Soc Toho Univ 16, 101–108 Yamagushi, K., Hashimoto, K., Matsuura, F (1968): Studies on a blue-green serum-pigment of eel IV Seasonal variation of concentration of pigment in serum Bull Jap Soc scient Fish 34, 826–835 Yamaguti, S (1952): Studies on the helminth fauna of Japan Part 49, Cestodes of fishes II Acta Med Okayama, 8, 1–78 Yamaguti, S (1959): Systema helminthum Vol II The cestodes of vertebrates New York Yamaguti, S (1963a): Systema helminthum Vol V Acanthocephala New York Yamaguti, S (1963b): Parasitic Copepoda and Branchiura of fishes New York Yamaguti, S (1971): Synopsis of digenetic trematodes of vertebrates Vols I & II, Tokyo Yamamoto, K., Morioka, T., Hiroi, O., Omori, M (1974a): Artificial maturation of Japanese eels by the injection of salmonid pituitary Bull Jap Soc scient Fish 40, 1–7 Yamamoto, K., Omori, M., Yamauchi, J (1974b): Oogenesis of the Japanese eel Bull Jap Soc scient Fish 40, 9–15 Yamamoto, K., Yamauchi, K (1974): Sexual maturation of Japanese eel and production of eel larvae in the aquarium Nature 251, 220–222 Yamamoto, M., Ueda, K (1978): Comparative morphology of fish olfactory epithelium: IV Anguilliformes and Myctophiformes Bull Jap Soc Sci Fish 44, 1207–1212 Yang, H N., Chen, H C (1996): The influence of temperature on the acute toxicity and sublethal effects of copper, cadmium and zinc to Japanese eel, Anguilla japonica Acta Zool Taiwan 7, 29–38 Yoshioka, M., Hamanda, K., Okazaki, T., Kajita, A., Shukuya, R (1968): Hemoglobins from erythrocytes of the eel, Anguilla japonica II Further studies on the properties of the two hemoglobins J Biochem., Tokyo, 63, 70–76 Zacchei, A.M., Tavolaro, P (1988): Lateral line system during the life cycle of Anguilla anguilla (L.) Boll Zool 3, 145–153 Ziepke, S (1974): Fliegen schürfende Aale Fisch u Fang 15, 323 Index Index Note: page numbers in bold denote figures and tables acanthocephalan infestations 318–19 N-acetylhistidine 33 adenomatose polyps 323 adrenal see chromaffin tissue adrenocortical homologue, interrenal tissue 53, 54 Aeromonas spp., infections 310–11 Africa East 100 Southeast 98–100, 99 age at migration 168–9 and salinity 180–1 yellow to silver eel transition 163–81 head width 180 age determination 163–5, 169 Agulhas Current 98 air, survival in air 184–5 American eel (A rostrata) 76–97 body length 83 continental occurrence 96–7 differentiation from European eel 79–81, 81 migration to Northern Europe 87 spawning areas and larvae 76–91 stocking 97 anaemia 34 anatomy/physiology 1–71 blood circulation 31–5 brain 47–51, 59–60 chromaffin tissue 53–5 corpuscles of Stannius 57–8 endocrine system 46–59 feeding/digestion 25–31 gastro-entero-pancreatic system 55–6 general anatomy, longitudinal section 37 gonads 36–46, 55 heart 31–3, 32, 56 interrenal tissue 53 kidney 35–6, 57 lymphatic system 33 musculature 19–20 nervous system and sense organs 59–71 respiratory organs and swimbladder 20–4 skeleton 2–8 skin 8–18 teeth 18–19 thymus gland 53 thyroid gland 51–2 ultimobranchial bodies 52–3 urinogenital system 35–46 urophysis 58 angiotensin 57 angling 246–54 injuries 326 Anguilla A ancestralis 93, 106–12 A anguilla 76–97, 92 A australis 94, 103–6, 176 A bicoloa 93, 98–100, 106–12 A borneensis 106–12 A celebesensis 93, 106–12 A dieffenbachii 94, 103–6, 176 A interioris 93, 106–12 A japonica 92, 100–3 A marmorata 93, 98–103, 106–12, 176, 177–8 A megastoma 93, 106–12 A mossambica 93, 98–100, 177–8 A nebulosa labiata 93, 98–100, 177 A nebulosa nebulosa 92, 98–100, 106–12 A obscura 93, 106–12 A reinhardtii 94, 106–12 A rostrata 76–97, 92 Anguilla genus characteristics of species 75 classification 74–6 distribution of species 92–4 intra-specific genetic differentiation 116 molecular systematics 114 teeth patterns, species compared 91 see also American; European: Indo-Pacific; Japanese eels Anguillicola spp infestations 314–20 and origin of Anguilla 322–3 annuli, age determination 163–5, 169 Antilles Current, spawning areas 79–81, 80 aquaculture see culture methods Argulus infestation 313, 319 articulare Asellus aquaticus 153 Asia, Japanese eel (A japonica) culture 295 association 183 group drifting 209–11 Atlantic eels common origin evolutionary origin 322 Sargasso Sea area 113, 114 see also American eel (A rostrata); European eel (A anguilla) Atlantic Ocean currents 88 directional choice 207–9, 208 Echo Bank 79 formation 113 harvest fluctuations 219–20 size/length data 194, 195 spawning areas 79–81, 80 atrial natriuretic peptides 56 attractants 68–9 auditory sense, and lateral line sense organs 70–1 400 Index Australasian species A australis 94, 103–6 A dieffenbachii 94, 103–6, 176 see also New Zealand Azores 84, 94 Azygia infestations, evolutionary origin of Anguilla 322 bacterial diseases 310–14 freshwater disease 310–11 saltwater disease 311–14 baits artificial 68 attractants 68–9 see also fishing methods Baltic Sea see North and Baltic Seas Bay of Biscay 84, 86, 89 silver eels, depth and temperature 192, 198–9 behaviour see habitat and behaviour Bermuda Islands 96, 155–6 von Bertalanffy formula, body size/length 175, 176 Black Sea 94–5 blood 32–4 eel blood toxicity to mammals 34 blood circulation 30–4 cardiovascular system 30–2, 56 gills 21 rete 23 body composition 338 fatty acids 340 iodine 340 body size/length 73, 74, 168–9 American and European eels 83, 131 European (N Atlantic Ocean) eels 85 in Mediterranean 121 theoretical patterns 175–81 tropical eels 112 von Bertalanffy formula 175, 176 yellow to silver eel transition 175–81 see also developmental stages; growth bone, decalcification bootstrap analysis 115 Borneo 106, 107 brain 46–51, 47, 49–51, 59–60 comparative anatomy 59–60 hypothalamo–hypophyseal system 48–51 pineal 47–8 bream, food competition 234 breathing see gaseous exchange burrowing 181–3 calcitonin, ultimobranchial bodies 52–3 calcitriol 57 calcium homeostasis, stanniocalcin 57–8 Canada 96–7, 96 St Lawrence River damming 150 harvest fluctuations 219–20 cardiac natriuretic peptides 56 cardiovascular system 30–2 heart 30–2, 31, 56 Caribbean Sea 81 cast nets 278–9 caudal fin caudal spot 15 cauliflower disease (EV2) 308–9 Celebes Island 106, 107 cestode infections 315–17 China eel processing 332 importation of glass eels (A anguilla) 295 chloride cells 22 Chondrococcus infection 314 chromaffin tissue 53–5 chromatophores 325 chromosome number 115 clamping gear 244–6 classification 74–6 cleithrum club cells commercial use see harvest; world trade and processing commisural organ 60 conger, food competition 235 continental shelf/slope, transition zone 119–123 coregonids, interspecific competition 233 corium 9–10 Corophium 153 corpuscles of Stannius 46, 57, 58 cortisol 53 crayfish, food competition 235 crustaceans Asellus aquaticus 153 infections 319 Argulus 313, 319 interspecific competition 235 mitten crab (Eriocheir) 152, 154 Cryptocaryon infection 314 culture methods 295–305 current status 295 economics and future 304–5 feeds and feeding 303–4 and growth rate 174 historical development 295–99 Europe 299 Japan 297–8 live storage 305 rearing systems 299–301 design feature methodss 300–1 water quality 300 rearing technology 302–4 recirculation technology 301 stocking and grading practices 302, 303 temperature and growth 296–7 dams and weirs eel ladders 143, 145–9, 148 Moses–Saunders Dam, St Lawrence River 150, 219–20 tube structures 147–9 Danube river numbers 95 turbine injuries 95 deformities, anomalies and other damage 323–9 colour anomaly 324–5 gross spinal abnormalities 324 injuries 326 pollutants 328–9 turbine injuries, Berg river 95, 326–7 Index Denmark harvest, biomass/yield 227 Kattegat, harvest, size/length data 194 mean annual catches 217, 218 see also Baltic and North Seas depth Atlantic Ocean spawning areas 89 records of larvae 78 swimming depth 203 and temperature 184, 192, 198–9, 202–6, 204–5 depth zone, and substratum 183–4 Deropristis infection 314 developmental stages 76–86, 77 body digestive system 25–7 gonads 38–42 musculature 19–20 pancreas 30, 55–6 pigmentation 11, 13–18 swimbladder 24 body composition 338 completion of larval stage 77, 119–123 and distribution of species 73–114 glass eels 129–31, 133 see also body size/length; growth diel periodicity feeding (yellow eels) 151–2 migration (elvers) 140–1 migration (silver eel spawning) 193–5 digestive organs 25–31 gastro-intestinal tract 25–8, 26 sectional views 25, 27 liver and gall bladder 29–30 pancreas 28–29, 30, 55–6, 56 directional sense, American and European eels 90–1 diseases and parasites 307–29 distribution of sexes 44–6 distribution of species 73–114, 92–4 American eel 76–97 continental occurrence 91–7 European eel 76–97 continental occurrence 91–97 Elbe 44–5 spawning areas and larvae 76–91 Indo-Pacific 98–112 North Pacific temperate zone 100–3 Southeast African ranges 98–100 Southwest Pacific, temperate zone 103–6 tropical 106–12 Japanese eel 92, 100–3 zoo-geographic relationships 112–14 DNA, mitochonrial DNA 114 ear 70–1 earth's magnetic field 90–1, 190, 196, 210 East Indian Archipelago 106 Echo Bank 79 ecology and behaviour 119–212 glass eels 119–137 economics see harvest; world trade and processing eel ladders 143, 145–9, 148 Germany 145–7 eel pass eel-pass tubes 149 Elbe River 141–2 eel processing see world trade and processing eel traps 145–9 eel virus (American, EVA) 310 eggs 42, 43 number calculation 43 electrofishing 183, 286–93 spinal abnormalities 324 electrolytes, regulation 35 elvers defined 17 economic use and furtherance 144–50 see also migration (elvers) endocrine system 46–59 entangling nets 277–8 estrogen 55 Europe catches 1963 and 1993 214 development of eel fishing 213–14 401 eel culture, historical development 299 NW arrival times of glass eels 120 harvest fluctuations 215–16 see also Baltic and North Seas; specific countries status of aquaculture 296 stocking 95, 132, 144–50, 235–9 see also world trade and processing European eel (A anguilla) 76–97 body length 83 continental ocurrence 91–7 culture status 295 differentiation from American eel 79–81, 81 N Atlantic Ocean, body length 85 spawning areas and larvae 76–91 see also culture European Inland Fishery Advisory Commission (EIFAC/FAO) 238–9 EVA, EV2, EVE (viral diseases) 308 evolutionary origin of eels 321–3 excretion, nitrogenous waste 22–3 eye 60–4, 62 sex dimorphism 61 size 62, 63 Faroe Islands 88 fatty acids, body composition 340 feeding activity and food consumption 150–2 culture methods 303–4 feed composition 303 diel periodicity 151–2 eel diets food availability 158–61 sea, brackish and fresh water 160–1 food competition 231–3 food composition and season 152–3 402 Index feeding (cont’d) food selection and body size/length 154–7 and head width, yellow to silver eel transition 157–8 interspecific competition 231–5 larvae, marine snow 43 (not) corpses/old food 158 predator–prey relationships 231–3 prey selection 68, 154–6, 162–3 stages of glass eels 133 yellow to silver eel stage 150–63 Fiji Islands 103 fins fish pass, vs juvenile eel pass 145–6 fishing development 213–15 see also harvest fishing methods 243–93 angling 246–54, 326 baits 68–9 electrofishing 183, 286–93, 324 entangling nets 277–8 impaling and clamping gear 244–6 lift nets and cast nets 278–9 light fishing 283–6 scoop nets 135 seines 279–80 stow nets 134–5, 266–71 anchored 268–9 otterboard 269–71 staked 267–8 traps 136, 254–76 derivatives 255–66 eel weirs in rivers 271–5 fyke nets 136, 261–3 large traps/ pound nets 263–6 small traps (tubular traps and pots) 256–61 stationary 271–6 streams and rivers 275–6 trawls 280–83 food see feeding France 125 exports to Spain 132 lagoons 230 Loire River glass eel catches 126, 130, 132 glass eel entry 134 Seine River, dyking 137 Sèvre Niortaise eel growth 130 tidal currents 126–8, 130 Somme River 137 fresh water, attractive substances in fresh water 124 freshwater disease 310–11 fungal infections 314, 315 fyke nets 261–3 gall bladder 30–1 gaseous exchange 21–4 skin 11 swimbladder 23–4 gastro-entero-pancreatic hormones 55–6 gastro-intestinal tract 25–8 German Bight arrival times 120–2 see also Heligoland; North and Baltic Seas Germany eel ladders and passes 145–50 Elbe glass eels eel passes 146, 147–50 Geesthacht Dam 137, 139, 141, 145–50 numbers 149–50 surface migration 12, 138 Elbe silver eels catches 192, 198–9 depth and temperature 192, 198–9 and yellow eels 223 Ems River 125, 126, 132 glass eel entry 134 export 132 Lake Constance, stocking rate and growth 238 lakes catches 221–2, 222, 227, 228–9 Sakrow 170, 229 Mosel fish pass 147 Rhine catches 222 stocking 95, 132, 144–50, 235–9 temperature, harvest fluctuations 219 trade and processing 334 glass eels 337 prices 334–6 see also Baltic and North Seas gill arches 6, 20–3 gill lamellae 20–3 glass eels 138 arrival times NW Europe 120 commercial use and harvest 132–37, 218–19 completion of larval stage 119–123 correlation of west wind, and invasion 218–19 defined 17 entry into fresh water 124–32 attractive substances in fresh water 124 first food consumption 131–2 light 126 onset of active migration 128–9 temperature barriers 124–5 tidal current 126–8 migration in ocean 119–24 approaching continental shelf 119–24 see also migration (glass eels) pigmentation 16–17 as measure of development 129–31 stage VIB 133, 137 pigmented see elvers salinity 206 stages 133 trade in 295, 302 trade and processing, prices 337 see also ecology and behaviour Goezia infection 313 golden eel see yellow eel gonadotropins 48–9 gonads 35–46, 37–9, 55 development 37–41 histological development 39–41, 40 sex determination 43–4, 302–3 sexual differentiation 39–46 see also reproduction Index Great Lakes 97 green eel, defined 17 Greenland, currents 88 growth and age, yellow to silver eel transition 163–81 differences between males and females 165–8 environmental factors 170–4 European eel vs nonEuropean eel 173 head width 169–70 interspecific differences 174–5 sex dimorphism 165–8 and temperature 296 see also body size/length; developmental stages growth hormone 50 Gulf of Mexico 81, 83, 97 Gulf Stream spawning areas 79–81, 80, 83–7, 88 transport of American vs European eels 84, 86–91, 220 habitat and behaviour 181–90 associations 183 burrowing 181–3 depth zone and substratum 183–4 lack of “water instinct” 185 surface migration 12, 138 survival in air 184–5 swimming depth 203–5 territoriality and homing ability 185–90 transitional periods 186 see also migration; orientation harvest commercial use glass eels 132–37, 218–19 for stocking 144–50 development of fishing 213–15 economic use of elvers 144–50 and environmental relationships 213–41 population density and catch per unit area 223–41 product quality 339–40 summary of yiel considerations 239–41 world 214 yearly fluctuations 215–20 Baltic Sea 216–18 Canada and North Atlantic 219–20 correlation of west wind and glass eel invasion 218–19 Europe and North Sea 215–16 seasonal temperature influence 219 yearly variations in yield 220–3 see also population density; world trade and processing head width, yellow to silver eel transition and age 180 feeding choice 157–8, 70 and growth 169–70 hearing and lateral line sense organs 70–1 heart 31–3, 32, 56 heavy metals, and deformities 328–9 Holland glass eels entry into fresh water 125 surface migration 12 Ijsselmeer, Wadden Sea 125, 188 catches and tides 127, 230 see also North and Baltic Seas homing ability 187–90 Hungary Lake Balaton 95, 153 stocking rate and growth 174, 238 hybridisation, possibility 87 hyomandibular 4–5 hypophysis, melatonin migration 64 hypothalamo–hypophyseal system 48–51 ice fish (Chamsocephalus) 34 Iceland 94 currents 88 Ichthyophthirius infection 312, 314 403 impaling and clamping gear 244–6 India 111 Indian Ocean, formation 113–14 Indo-Pacific 97–114 North Pacific temperate zone (A japonica, A marmorata) 100–3 number of species 97–8 Southeast African ranges (A marmorata, A nebulosa, A mossambica and A bicolor) 98–100 Southwest temperate zone (A australis, A dieffenbachii, A marmorata, A obscura) 103–6 tropical eel species 106–12 injuries caused by anglers 326 turbine injuries Berg river 326–7 Danube river 95 insecticides 328–9 international trade see world trade and processing interrenal tissue 53, 54 intersex 43–4 iodine, body composition 340 Ireland eel growth 171–2 eel prey 155 lake yields 228 Ireland (Northern) 132, 171–2 Bann catches 198–9 Lough Neagh catches 171–2, 227 Lough Neagh stocking 237 Irminger Current 88 islets of Langerhans 29 Italy Comacchio 174, 213, 230 Lake Como 169 Japan eel culture, historical development 297–8 processed ell imports 332 procuring glass eels 136 trade and processing, price levels 333, 334–9 404 Index Japanese eel (A japonica) 92, 100–3 culture status 295 skull 2–6 vertebral column 6–8 Japanese Sea, harvest, size/length data 194, 195 Java 106–10 juvenile eels see elvers; migration (elvers/juvenile eels) karyotype, chromosome number 115 Kenya 100 kidney 35–6, 57 interrenal tissue 53, 54 kidney tumours 323 kidney (viral) disease (EVE) 310 Korea 103 Kuroshio Current 100–2 Labrador Current 88 ladders 143, 145–9, 148 Lake Balaton 95, 153 stocking rate and growth 174, 238 lampreys, migration 139–40 Langerhans islets 29 larvae body size/length 73, 74, 77 completion of larval stage 77, 119–123 on continental shelf/slope 119–123 depth recorded 78 food, first food consumption 131–2 food (marine snow) 43 habitats and migrations 76–91 migration during completion of larval stage 119–123 pigmentation 14 pre-leptocephalus larva 88 transition into glass eel 119 see also developmental stages lateral line sense organs 70–1 mandibular lateral line 70–1 lepidotrichia leptocephalus larva cranial skeleton first recorded 76 “L brevirostris” see European eel (A anguilla) “L grassi” see American eel (A rostrata) see also larvae life cycle, phases 163–5 lift nets and cast nets 278–9 light glass eels entry into fresh water 126 migration onset 140–4 silver eels, migration onset 140–4, 193–5 light fishing 283–6 liver and gall bladder 30–1 lobster, food competition 235 Loire River see France long-finned eel 104 low pressure areas (cyclones), and migration 197–8 lunar phase juvenile eel activity 144, 193 migration of silver eels 196–7 and swimming depth 203 lymphatic system 33 Madagascar 98–100 Marianas Islands 98, 101 Meckel's cartilage Mediterranean Sea 76–9 body size/length 121 distances travelled 211 temperature and depth, preferred depths 203, 204 melanin, retinal 64 melanophores 13–18 melanotropes 50 microsatellite loci 116, 117 microseismic oscillations 197–8 migration (elvers/juvenile eels) 137–50 dependence on environmental conditions 137–44 diel periodicity 140–1 numbers, North Sea tributaries 149–50 survival in air 184–5 water temperature and light 140–4 see also migration (yellow eels) migration (glass eels) approaching continental shelf 119–24 arrival times NW Europe 120 completion of larval stage 119–123 tidal currents 122, 126–8 migration (silver eel spawning) 190–212 active 86–91 correlation with lunar phases 196–7 diel periodicity 193–5 diel periodicity and light influences 193–5 directional sense, American and European eels 90–1, 202 effects of weather and hydrography 197–212 behaviour and speed 209–12 directional choice in ocean 207–9 low pressure areas (cyclones) 197–8 salinity 206–7 temperature and depth 202–6 tidal currents 199–200 water level and current in streams 198–9 wind and currents 201–2 evidence from predatorcaught eels 87–8 and olfaction 69, 90 peak activity 191–2 seasonal pattern 191–3 subterranean waters 196–7 surface migration 209–11 timing 189 vision 90 migration (yellow eels) 190 New Zealand 193–4 peak activity 191 size and age at migration 168–9 subterranean waters 196–7 see also migration (elvers/juvenile eels) mitochondrial DNA 114–17 mitten crab (Eriocheir) 152, 154 moon see lunar phase Moses–Saunders Dam, St Lawrence River 150, 219–20 mucus secretion 9–11 Index musculature 19–20 gut 27 Myxidium infection 312 Na-K-ATPase 22 nasal cavity see olfaction and taste nematode infestations 314, 317–18, 320 nervous system and sense organs 59–71 brain 59–60 eye 60–4 hearing and lateral line sense organs 70–1 olfaction and taste 65–70, 65–6 Netherlands see Holland; North and Baltic Seas neurohypophyseal hormones 50–1 neuropeptide Y 53 New Guinea 106–11 New Zealand 100, 104–6 Australasian species 94, 103–6, 176 harvest biomass/yield 223, 224 low fishing pressure 227 and salmonids 232 size/length data 194, 195 migration (yellow eels) 193–4 moon phase, juvenile eel activity 144 prey 156 tidal rhythms and catches 128, 129 nitrogenous waste, excretion 22–3 North Atlantic see Atlantic Ocean North and Baltic Seas 94, 125, 183–4 directional choice 207–9, 208 distances travelled 211 food choices 159 harvest fluctuations 215–16 mean monthly catch 221 size/length data 194 harvest fluctuations 129, 137, 216–18 Heligoland 170, 183, 187 eel prey 154, 162 lunar phase activity 196–7 migration routes and tidal currents 199–200 preferred depths 203, 204 temperature and depth, preferred depths 203, 204 various waters biomass 224–6, 230 surface areas 230 North Equatorial Current 100–1 Norwegian Current 88 Nyasa, Lake 100 oceans, surface currents (Feb/March) 82 olfaction homing ability 187–90 and migration 69, 90 and taste 65–70, 65–6 oocytes see eggs oogenesis 42 operculum 5–6 orientation depth and temperature 202 directional choice in ocean, migration (silver eel spawning) 207–9 earth's magnetic field 90–1, 190, 196, 210 homing ability 187–90 olfaction sense 68 salinity 207 silver eel spawning migration, American and European eels 90–1, 202 osmoregulation 22, 27–8 otoliths age determination 163–5, 169 and salinity 122, 124 ovarian cysts 324 ovary see gonads oxygen, gaseous exchange 11, 21–4 Oyashio Current 102 Pacific North Pacific temperate 405 zone (A japonica, A marmorata) 100–3 Southwest temperate zone (A australis, A dieffenbachii) 103–6 see also Indo-Pacific palatopterygoid bone pancreas 28–30, 30, 55–6, 56 Paraquimperia spp infestations 317 and origin of Anguilla 322–3 parasite infestations 314–21 and eel origin 321–3 pectoral girdle and fins 8, peptide YY 53 perch Perca flavescens, food competition 234 perch Perca fluviatilis 153 pesticides 328–9 Philippine Islands 108 phylogenetic relationships and population genetics 114–17 evolutionary origin of eels 321–3 inter-specific genetic differentiation and Atlantic eel paradigm 114–17 molecular systematics of genus Anguilla 114 physostome fish 25 pigmentation 11, 13–17 anomalies 324–5 development 16, 129–30 as measure of development 129–31 stage VIB in glass eel development 133, 137 yellow 16–17 pineal organ 15, 48 pituitary, hypothalamo– hypophyseal system 48–51 plecospondyly 324 pneumatic duct 23 Poland 228 stocking 237 pollutants avoidance 184–5 and deformities 328–9 406 Index population density and catch per unit area 223–41 biomass, various waters 224–5 coastal waters 231 interspecific competition 231–5 coregonids 233 crustaceans 235 salmonids 231–3 regional differences 223–30 population density and catch per unit area (cont’d) stocking to improve yields 235–9 yield classification 239–41 population genetics 114–17 porphyropsin 64 post-larval ecology and behaviour see ecology and behaviour predator–prey relationships 231–3, 239–40 prey selection 68, 154–6, 162–3 predator-caught eels, evidence of migration 87–8 premaxillo-ethmo-vomerine bloc 2, teeth 18 prolactin 50 protein electrophoresis 114–15 protozoal infections 314–23 Pseudodactylogyrus infection 313, 314, 315 Pseudomonas anguilliseptica infection 310 pterygoid bone rearing systems, eel culture 299–301 references 341–97 Reissner fibre complex 60 renin–angiotensin system 57 reproduction spawning behaviour 42 see also gonads respiratory organs and swimbladder 20–4 rhodopsin 64 Rio Minho 125 Russia, stocking 172 Rutilus rutilus 153 salinity age and growth 180–1 and blood 34 glass eel 206 migration (silver eel spawning) 206–7 orientation 207 rivers, juvenile eel activity 144 Sr:Ca content of otoliths 122, 124 salinity front, perception and spawning 89–90 salmonids food competition 231–3 predator–prey relationships 231–3 saltwater eel disease 311–14 Saprolegnia infection 312, 314 Sargasso Sea 84, 89–91 common origin of Atlantic eels 113, 114 temperature and depth 205 scales 11–12 age determination 163–5 scoop nets 135 seines 279–80 sense organs 59–71 lateral line 70–1 serotonin 53–4 sex determination 43–4 aquaculture 302–3 sex dimorphism eyes 61 growth 165–8 sexual differentiation 40–6 short-finned eel 104 silver eels harvest, size/length data 194, 195 stage, defined 17 see also migration (silver eel spawning); yellow to silver eel transition skeleton 2–8 pectoral girdle and fins skull 2–6, 2–4 vertebral column 6–8 skin 8–18 epidermis and corium 10 gaseous exchange 11 mucus secretion 9–11 pigmentation 11, 13–17 scales 11–12 structure and function 8–13 skull 2–6 comparative studies 2–3 skull spot 14, 15 smell see olfaction and taste smoking 340 sodium, gill function 22 somatotropins 50 South African eels 98–100, 99 prey 155 South Equatorial Current 103–4, 110 Spain 96 Rio Minho 125 spawning areas 76–91 Atlantic Ocean 79–81, 80 depth 89 Sargasso Sea 84, 89–91, 113–14 spawning behaviour 42 spawning migration see migration (silver eel spawning) speed and distances covered 86, 209–12 sporozoan infections 315 Sr:Ca content of otoliths, and salinity 122, 124 stages see developmental stages; larvae; elvers; glass, silver and yellow eels stanniocalcin 57–8 Stannius, corpuscles 46, 57, 58 stocking American eels 97 Germany 95, 132, 144–50, 235–9 grading practices, culture methods 302–3 and grading practices eel culture 302–3 harvest of eels 144–50 improvement of yields 235–9 Index Russia 172 storage methods 305 stow nets 134–6, 266–71 anchored 268–9 otterboard 269–71 staked 267–8 Strait of Gibraltar 79 streams, water level and current, migration (silver eel spawning) 198–9 subterranean waters, migrations 196–7 Sumatra 106–11 surface migration Elbe glass eels 12, 138 silver eels 209–11 survival in air 184–5 hypoxia 21–2 swimbladder 22–4, 23 swimming depth 203 swimming speeds 86, 209–12 tagging studies see migration; orientation Tamura Net distances 115 taste sense 69–70 taxonomy 74–6 see also phylogenetic relationships teeth 6, 17–18 comparative patterns 18, 91 premaxillo-ethmo-vomerine bloc 17–18 temperature barrier to glass eel entry into fresh water 124–5 and depth 184, 192, 198–9, 202–6, 204–5 migration (silver eel spawning) 202–6 and growth 296 and sex determination 46 yearly fluctuations, harvest 219 yellow eel activity 220 tench, food competition 234 territoriality and homing ability 185–90 testis see gonads Tethys Sea 113, 114, 321, 321–3 origin of eels 321–3 Texel Current, glass eel catches 123 thigmotaxis 181–3 thymus gland 53 thyroid gland 51, 52 thyroid-stimulating hormone 49 Tiber River 125, 128 tidal currents glass eels 122, 126–8 migration (silver eel spawning) 199–202 see also lunar phase trade see world trade and processing traps 136, 254–76 covert 254–5 derivatives 255–66 eel weirs in rivers 271–5 large traps/ pound nets 263–6 small traps (tubular traps and pots) 256–61 stow nets 266–71 anchored 268–9 otterboard 269–71 staked 267–8 tropical eel species 106–12 prey 153 Tubifex 152 turbine injuries 95, 326–7 UK arrival times 120–1 Wales, growth rate of male eels 170–1 see also Ireland; North Sea ultimobranchial bodies 52–3 urinogenital system 35–46 gonads 36–46, 55 kidneys 35–6, 57 urophysis 58 ventricular natriuretic peptides 56 vertebral column 6–8, American and European spp compared 79–80, 81 comparative studies spinal abnormalities 324, 325 Vibrio anguillarum infection 34, 311–14 viral diseases 307–10 407 cauliflower disease (EV2) 308–9 eel virus American (EVA) 310 kidney disease (EVE) 310 visual sytem eye 60–4 and migration 90 von Bertalanffy formula, body size/length 175, 176 Wadden Sea 125 catches and tides 127 Wales, growth rate of male eels 170–1 walleye, food competition 234 wastewater pollution effects on eels 328 reaction to discharges 184–5 "water instinct" (lack of) 185 water quality 301 weather and hydrography 197–212 see also migration (silver eel spawning) weirs eel ladders 143, 145–9, 148 eel weirs in rivers 271–5 whale prey, evidence of eel migration 87 whitefish, interspecific competition 233 wind-dependent currents, migration (silver eel spawning) 201–2 winds, west wind, glass eel invasion 218–19 world trade and processing 331–40 commercial product quality 339–40 Germany 334 international trade 331–4 prices 333, 334–9 fluctuations 334–6 levels in different countries including glass eels 336–9 world status of aquaculture 296 see also harvest xanthochromatosis 325 408 Index yellow eel defined 15, 150, 325 leaving winter habitat 221 pigmentation 15 see also migration (yellow eels) Yellow Sea 102 yellow to silver eel transition 150–90 age and growth 163–81 age determination 163–5 body length calculations 175–81 annual and seasonal differences 179–80 differences between males and females 179 head width and age 180 length and weight 175–6 plumpness and body size/length 179 salinity 180–1 species differences 176–9 environmental factors 170–4 growth differences between males and females 165–8 head width and growth 169–70 interspecific differences in growth 174–5 size and age at migration 168–9 feeding 150–63 activity and food consumption 150–2 diet and food availability 158–61 food choice and head width 157–8 food composition and season 152–3 food selection and body size/length 154–7 prey selection 162–3 habitat and behaviour 181–90 depth zone and substratum 183–4 occupation of tubes or cavities and thigmotaxis 181–3 survival in air 184–5 territoriality and homing ability 185–90 lateral line sense organs 71 Zambesi river system 100 Zimbabwe 100 ... clear description of the skull of the Japanese eel (Anguilla japonica) (Figs 1.1 and 1.2) The skull and other parts of the adult eel s (A anguilla) skeleton, as well as that of other Anguilliformes... (1960) studied the skin of 10 species and found that the eel had the thickest epidermis But in the eel, unlike other teleosts, the corium, particularly that on the head, is thicker than the epidermis... absent in adult eels at least On the other hand, the pteroticum extends far behind and forms, with the exoccipital, the sharp outside edge of the backward part of the head In Anguilla, lacrimal,