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Harp Seals, Man and Ice w. • dab —4 _Ire ...Ob.._ 4r 'fflIOMMILF7 Frontispiece: Moulting patch of harp seals at the "Front" ice, Newfoundland, April 25, 1976. Canadian Special Publication of Fisheries and Aquatic Sciences 114 Harp Seals, Man and Ice D.E. Sergeant Department of Renewable Resources, McGill University, Macdonald Campus, 21, 111 Lakesh ore, Ste-Anne-de-Bellevue, Quebec, Canada H9X 1C0 Scientific Excellence Resource Protection & Conservation Benefits for Canadians DEPARTMENT OF FISHERIES AND OCEANS OTTAWA 1991 ©Minister of Supply and Services Canada 1991 Available in Canada through Associated Bookstores and other booksellers or by mail from Canada Communication Group - Publishing Supply and Services Canada Ottawa, Canada KlA 059 Catalogue No. Fs 41-31/114E ISBN: 0-660-14052-7 ISSN: 0706-6481 DF0/4419 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted by any means, electronic , mechanical, photocopying, recording or otherwise, without the prior written permission of the Canada Communication Group — Publishing, Ottawa, Canada K lA 0S9. Printed on recycled paper Think Recycling! Pensez à recycler ! Published by Publié par Fisheries Pêches Mel and Oceans et Océans Communications Direction générale Directorate des communications Ottawa KlA 0E6 Communications Directorate Director, Scientific Publications: John Camp Editorial and Publishing Services: Gerald J. Neville Correct citation for this publication: SERGEANT, D. E. 1991. Harp seals, man and ice. Can. Spec. Publ. Fish. Aquat. Sci.114: 153 p. iv Contents Abstract/Résumé VIII Introduction and Acknowledgements IX Chapter I. Origins and Names 1 Summary 1 Classification and Evolution 1 Past Distribution 3 Vernacular Names and Other Terminology 7 Chapter II. Physiology and Behaviour 11 Summary 11 Senses and Locomotion 11 Life in Cold Water 12 Hearing and Underwater Sound 12 The Moult 13 Fatness 14 Social Behaviour 15 Chapter III. Age, Reproduction and Growth 17 Summary 17 Age Determination 17 Reproduction 18 The Male 18 The Female 19 The Sex Ratio 20 Foetal Growth 22 Growth in Weight 23 Growth in Length 25 Juvenal Pelage and Growth 26 Pelage Pattern 28 Age Changes in Pelage Type 28 Chapter IV. The Harp Seal's Annual Cycle: Distribution and Migrations 31 Summary 31 Distribution 31 Migrations 33 A. The Newfoundland-Gulf of St. Lawrence Population 33 1. Southward Migration 33 2. Wintering 37 3. Whelping 38 a) Location of whelping ice 38 b) Frequency of various whelping patterns 40 c) The Meccatina patch 41 d) Density of animals in ice 42 4. Moult 44 5. Northward Migration 45 6. Summering 46 a) Greenland 46 b) Arctic Canada 50 7. Mixing of Gulf and Front Herds 54 8. Site Tenacity 56 B. The Jan Mayen Population 56 C. The White Sea Population 58 Effect of Climate upon Whelping Sites 60 Discussion 61 a) Significance of the Whelping Sites 61 b) Stock Relationships 62 Orientation 62 Chapter V. Food and Feeding 65 Summary 65 Introduction 65 Western Herds 65 Central Herds 69 Eastern Herds 69 Composition of the Food 70 How Often and How Much do Harp Seals Eat? 70 A Decline in Feeding Rate in the St. Lawrence Estuary 71 Calculation of Food Consumption 72 Discussion 72 Chapter VI. The Young Seal 73 Summary 73 Birth 73 Season of Births and Length of Lactation 73 A. Introduction 73 B. Northwest Atlantic 73 1. Whelping 74 2. Mating 75 3. End of Lactation 75 C. Other Areas 76 D. Discussion 76 Lactation 76 Lactation and Pup Growth 76 Lactation and Time of Day 78 Energetics of Early Life 78 Early Mortality 79 Mortality of Young in Loose Ice 80 Mortality Due to Ice-Rafting 81 First Movements of Young Seals 82 An Experiment on Orientation 83 The Solitary Young Seal 85 Chapter VII. History of Exploitation and Management 89 Summary 89 The Jan Mayen Population 89 The White Sea Population 91 Shore Fisheries 91 Offshore Fisheries 91 The Western Herds 93 A. Landsmen 93 Icefield Fishermen 93 Summer Fishermen 93 Autumn Fishermen 94 Winter Fishermen 94 Discussion 95 B. Offshore Fisheries 95 Chapter VIII. Population Dynamics, Size and Yields 101 Summary 101 Rational Exploitation 101 Population Dynamics 102 Population Estimates: Techniques and Results, Especially in the Western North Atlantic 103 1. Photographic Aerial Survey 103 2. Mark and Recapture Analysis 104 1-2. Aerial Photo-Survey and Capture-Recapture Tagging Compared 105 vi 3. Maximum Catch of Young 106 4. Catch and Survival Method 106 5. Historical Studies: Catch and Effort Analysis of Maximal Sustainable Yield 107 6. Sequential Population Analysis 109 Discussion 111 112 Results, Other Areas 1. Jan Mayan 112 2. White Sea 112 Chapter IX. Natural Regulation of Harp Seal Populations 115 Summary 115 Introduction 115 Predation 115 Parasites 116 Shortage of Space and Climatic Change 116 Food Limitation for Young Seals 116 The Young During the Rest of the Year 118 Reproductive Rates of Adults 119 Discussion 120 Knowledge from Other Species 120 Theory 121 Application to Harp Seals 121 Chapter X. The Importance of Harp Seals to Man 123 Summary 123 Living with Ice 123 Production, Yield and Value 124 Effort 124 Harp Seals and Other Fisheries 126 a) Human Effects on Seals 126 b) The Seals' Effects on Humans 126 Codworm 127 Chapter XI. Pollution and Harp Seals 129 Summary 129 Oil Contamination 129 Organochlorines 131 Mercury 131 Chapter XII. Prospect 133 Hunting 133 Tourism 133 Envoi 133 References 135 Appendices 145 I. Details of Female Reproductive Rates, Gulf of St. Lawrence, 1969-87 145 II. Some Seal Recipes 149 Index 151 vii SERGEAN T, D.E. 1991. Harp seals, man and ice. Can. Spec. Publ. Fish. Aquat. Sci. 114: 153 p. This book reviews the biology and population dynamics of the harp seal, Phoca groenlandica Erxleben, the history of its hunting over several centuries, and its eventual conservation. This is one of the most abundant of the world's hair seals, which has long been an important resource for peoples living on seasonally ice-bound coasts of the North Atlantic Ocean. The author treats the biology of the species as a whole, not only on the coasts of eastern Canada, but also of Greenland and northern Europe, and the history of the hunt in all these regions. Knowledge of the behav- iour of pack ice on these coasts gives a background to both the ecology of the seals and the economies of the hunt. Advances in knowledge of the biology and population dynamics of harp seals led to their successful management as a hunted species, but popular sentiment, concerned with hunting practices, brought about a loss of markets so that catches greatly decreased. Consequently, many present problems are those of an abundant predator species, interact- ing with human finfish fisheries. Ce livre donne un compte rendu de la biologie et de la dynamique des populations du phoque du Groenland Phoca groenlandica Erxleben, l'historique de la chasse au cours des siècles et des efforts actuels de conservation de l'espèce. Une des plus abondantes parmi toutes les espèces de phoques à poil ras, le phoque du Groenland constitue depuis longtemps une importante ressource pour les habitants des côtes de l'Atlantique Nord bloquées par les glaces une partie de l'année. L'auteur examine la biologie de l'espèce, non seulement sur la côte est du Canada, mais aussi sur les côtes du Groenland et du nord de l'Europe; il traite aussi l'historique de la chasse dans ces régions. Des renseignements sur le régime du pack sur ces côtes mettent en contexte l'écologie du phoque du Groenland et le côté économique de la chasse. L'accumulation de connaissances sur la biologie et la dynamique des populations du phoque du . Groenland a mené à une gestion équilibrée de la chasse, mais les pressions exercées par le grand public, préoccupé par les méthodes de chasse, ont entraîné la perte de marchés. Le nombre d'animaux tués a donc nettement diminué. Par conséquent, nous faisions face à un problème de prédateurs abondants dans les pêcheries de poisson exploitées par un autre prédateur, l'homme. viii Introduction and Acknowledgements The great interest aroused concerning the hunting of with aerial surveys, and in 1964 and 1966 headed teams harp seals since about 1965 has made the writing of a of workers carrying out capture/recapture tagging book on the biology of the species a prime need, since from a helicopter and an icebreaker respectively. In no work exists in the English language which attempts 1969, Dr. Smith opened up the possibility of collecting to cover the scope of the species' biology and fisheries. data from hunters in the estuary of the St. Lawrence. A great amount of research has, however, been carried Dr. M.M.R. Freeman provided first-hand data on harp out, increasing exponentially since the early 1950's, in seals from the Canadian high arctic. Canada, Denmark, Norway and the Soviet Union, all In the 1950's, Mr. John Clowe and Mr. Charles Rose countries which have possessed or administered impor- were my field companions and taught me the skills of tànt fisheriès for harp seals. I have tried to piece this in- working and travelling on ice. During the 1960's and later, formation together, but since my first-hand research has Brian Beck, Dr. Paul Brodie, Ingram Gidney, Clive been in the western North Atlantic, I necessarily give more Nicol, Hank Killiaan and C.W. Britton, and especially weight to this area. Wybrand Hoek carried out much of the aerial survey, The writing of a book gives a spurious finality to the collecting and analysis of specimens and the tagging research. In fact research has opened as many problems of seals, and contributed ideas in field and laboratory as it has solved.