THE UNIVERSITY LIBRARY PROTECTION OF AUTHOR ’S COPYRIGHT This copy has been supplied by the Library of the University of Otago on the understanding that the following conditions will be observed: 1. To comply with s56 of the Copyright Act 1994 [NZ], this thesis copy must only be used for the purposes of research or private study. 2. The author's permission must be obtained before any material in the thesis is reproduced, unless such reproduction falls within the fair dealing guidelines of the Copyright Act 1994. Due acknowledgement must be made to the author in any citation. 3. No further copies may be made without the permission of the Librarian of the University of Otago. August 2010 ,_ Individual Identification, Population Dynamics and Moult of the New Zealand Sea Lion at Otago. Shaun McConkey A thesis submitted for the degree of Master of Science in Marine Science at the University of Otago, Dunedin, New Zealand. April, 1997 11 Abstract A photographic record was kept of all New Zealand sea lions seen at seven study sites in Otago, New Zealand, throughout 1995. Seventy-nine sea lions were individually identified using distinctive features on the flippers, face and body such as rips, nicks and surface scars and estimates of age class. The most commonly used features were those found on the periphery of both the fore and hind flippers. Over 90% of individual sea lions seen were identifiable. The computer program written in this study to improve the speed and accuracy of identying sea lions was found to vary in effectiveness depending on the experience of the researcher. Using the program experienced researchers correctly matched animals more rapidly and more frequently than inexperienced researchers. Approximately 75% of animals identified at Otago Peninsula were present for at least six months of 1995. All individuals identified in 1994 were also seen in 1995, indicating a majority of resident animals. Numbers of sea lions ashore reached a maximum during spring and autumn and a minimum during winter and summer. Low numbers during summer were related to an absence of older animals. Low numbers during winter appeared to be due to a change in haul-out behaviour. Diurnal activity was investigated via the presence and absence of one-year old male sea lions at Roaring Bay, South Otago. Arrivals and departures peaked at mid-morning and mid-afternoon, behavioural activity peaked at 1400h, and the animals showed virtually no nocturnal activity. Only three females were present at Otago Peninsula during the study period: a breeding female and her two offspring, the first pups to be born on the mainland of New Zealand in recorded history. The timing and pattern of moult was recorded for male sea lions. Younger males moulted first with two-year olds beginning in December- January. Generally moult occurred later for each successive age class. Animals older than four began moulting in March- April. The exception was the one-year old age class, which moulted at a similar time to animals five years and older, but only went through a partial moult. 111 Acknowledgements I would like to acknowledge the assistance of the Department of Marine Science (Otago University), the Department of Conservation, the Department of Zoology (Otago University), and all those who accompanied me to the beach in support of my work. Special thanks are due to my supervisors, Chris Lalas and Steve Dawson, as well as Karen Baird, Marj Wright, Brian Murphy and Sonja Heinrich for aid above and beyond the call of duty. Thankfully attitudes have changed since 1894. "There is certainly no sufficient reason to continuously protect the sea lions - they simply occupy and defile considerable areas on the coast that could be utilised for pastoral purposes" Joyce, 1894 ,, IV 'I Table of Contents List of Tables ...................................................................................... vii List of Figures .................................................................................... viii .~ Chapter 1 General introduction ....................................................................... 1 1.1 Pinnipeds (Order Carnivora, Suborder Pinnipedia) ........................................ 1 1.2 Sea lions ......................................................................................... 1 l.3 New Zealand sea lion .......................................................................... 2 l.4 Conservation Status of the New Zealand sea lion .......................................... 6 1.5 Sea lions at Otago Peninsula and this study ................................................. 6 Chapter 2 Study sites ................................................................................... 9 2.1 Otago Peninsula ............... ·.· ............................................................... 9 2.2 South Otago ................................................................................... 11 c- Chapter 3 Identification of individuals ............................................................. 13 3.1 Introduction ................................................................................... 13 3.2 Methods ....................................................................................... 15 <I· 3.3 Results ......................................................................................... 17 3.4 Discussion ..................................................................................... 27 Chapter 4 Computer program ....................................................................... 29 4.1 Introduction ................................................................................... 29 4.2 Methods ....................................................................................... 30 4.3 Results ......................................................................................... 31 4.4 Discussion ..................................................................................... 35 Chapter 5 Number of identified individuals ....................................................... 36 5.1 Introduction ................................................................................... 36 5.2 Methods ....................................................................................... 37 v 5.3 Results......................................................................................... 38 5.4 Discussion..................................................................................... 47 Chapter 6 y Population dynamics of males.. 51 6.1 Introduction................................................................................... 51 6.2 Methods . 53 • 6.3 Results......................................................................................... 55 6.4 Discussion ..................................................................................... 71 Chapter 7 Movement and behaviour of juvenile males........................................... 75 7.1 Introduction . 7 5 7.2 Methods ....................................................................................... 76 7.3 Results ......................................................................................... 79 7.4 Discussion..................................................................................... 87 Chapter 8 The first recorded births of New Zealand sea lions on the mainland............... 88 ,._ 8.1 Introduction................................................................................... 88 8.2 Methods ....................................................................................... 90 8.3 Results ......................................................................................... 91 8.4 Discussion..................................................................................... 97 Chapter 9 Annual pelage moult of males . 100 9.1 Introduction ................................................................................... 100 9.2 Methods ....................................................................................... 101 9.3 Results ......................................................................................... 102 9.4 Discussion ..................................................................................... 108 Chapter 10 General discussion ....................................................................... 110 10.1 This study .................................................................................... 110 10.2 Further research ............................................................................. 112 References . 113 Appendix 1 Sea lion database .................................................................... 122 Vl Appendix 2 Computer program ................................................................ 125 Appendix 3 Sighting patterns for sea lions. Significant beach preference indicated. (Statistical method is log-likelihood ratio with Williams' correction) ....... 139 Appendix 4 Ethics approval.. ................................................................... 141 Appendix 5 Department of Conservation permit ....................... : ..................... 142 Vll 'j· List of Tables Table 3.1 Sightings of known-age male sea lions 1991 - 1995 (data for 1991, 1992 & 1993 from C. Lalas, pers. comm.) ....................................................... 15 Table 4.1 Summary of computer program testing results .......................................... 32 Table 4.2 Summary of p. values from a multiple anova ............................................ 34 Table