ECOLOGY OF PACIFIC WHITE-SIDED DOLPHINS (LAGENORHYNCHUS OBLIQUIDENS) IN THE COASTAL WATERS OF BRITISH COLUMBIA, CANADA Erin Ashe A Thesis Submitted for the Degree of PhD at the University of St Andrews 2015 Full metadata for this item is available in St Andrews Research Repository at: http://research-repository.st-andrews.ac.uk/ Please use this identifier to cite or link to this item: http://hdl.handle.net/10023/9483 This item is protected by original copyright Ecology of Pacific white-sided dolphins (Lagenorhynchus obliquidens) in the coastal waters of British Columbia, Canada Erin Ashe This thesis is submitted in partial fulfilment for the degree of PhD at the University of St Andrews August 2015 1. Candidate’s declarations: I, Erin Ashe, hereby certify that this thesis, which is approximately 65,000 words in length, has been written by me, that it is the record of work carried out by me and that it has not been submitted in any previous application for a higher degree. I was admitted as a research student in September, 2009 and as a candidate for the degree of PhD in September 2010; the higher study for which this is a record was carried out in the University of St Andrews between 2009 and 2015. (If you received assistance in writing from anyone other than your supervisor/s): I, Erin Ashe, received assistance in the writing of this thesis in respect of grammar and spelling, which was provided by Rob Williams. Date 21 August 2015 signature of candidate 2. Supervisor’s declaration: I hereby certify that the candidate has fulfilled the conditions of the Resolution and Regulations appropriate for the degree of Philosophy in the University of St Andrews and that the candidate is qualified to submit this thesis in application for that degree. Date 21 August 2015 signature of supervisor 3. Permission for electronic publication: (to be signed by both candidate and supervisor) In submitting this thesis to the University of St Andrews I understand that I am giving permission for it to be made available for use in accordance with the regulations of the University Library for the time being in force, subject to any copyright vested in the work not being affected thereby. I also understand that the title and the abstract will be published, and that a copy of the work may be made and supplied to any bona fide library or research worker, that my thesis will be electronically accessible for personal or research use unless exempt by award of an embargo as requested below, and that the library has the right to migrate my thesis into new electronic forms as required to ensure continued access to the thesis. I have obtained any third-party copyright permissions that may be required in order to allow such access and migration, or have requested the appropriate embargo below. ii The following is an agreed request by candidate and supervisor regarding the electronic publication of this thesis: Add one of the following options: (i) Access to printed copy and electronic publication of thesis through the University of St Andrews. Date 21 August 2015 …… signature of candidate Date 24 August 2015 … signature of supervisor…… iii Abstract The ecology of Pacific white-sided dolphins (Lagenorhynchus obliquidens) in the Broughton Archipelago, British Columbia (BC), Canada was explored through photo-identification, mark- recapture, acoustics, and sociality studies. New population parameters were estimated from photo-ID data for the first time in this species. Abundance was highly variable, ranging from 546 (95% CI: 293-1,018) to 2,889 (95% CI: 1,424-5,863), after accounting for the proportion (0.57; 95% CI: 0.55 - 0.60) of marked dolphins. A “match uncertainty” analysis showed that less strict matching criteria caused negative bias in abundance estimates and an apparent improvement in precision. Estimates of survival rate ranged from 0.907 (SE=0.03) to 0.989 (SE= 0.066). Robust design analyses revealed random temporary emigration movement at 0.14 (SE=0.318) annually and no movement seasonally. The study revealed new evidence for philopatry and sociality: some individuals were resighted over 19-year periods, and associated pairs more than a decade apart. Evidence was found for a high degree of sociality. The mean proportion of calves was estimated as 0.0597 (SE=0.0083, 95% CI: 0.045-0.079) per capita, translating to an average probability of pregnancy in adult females of 0.238 (95% CI: 0.180- 0.316) and an average interbirth interval of 4.2 years. Approximately 3.9% of dolphins bore injuries from killer whales, but only 0.5% showed evidence of interactions with fishing gear or propellers. Acoustic evidence for population structure was equivocal, but warrants additional, targeted research. Population viability analysis predicted an average rate of annual decline of - 0.122 (95% CI: -0.143 to -0.101), given a range of input values in a sensitivity test, over the next 50 years. i Acknowledgments First, I would like to thank Prof. Phil Hammond for taking me on as a student, for always being available, offering insightful and practical advice, and holding my work to something approaching his impeccably high standards. I am extraordinarily grateful to have had Prof. Hammond as a supervisor and know my work has benefitted from his expertise, perspective and extraordinary commitment to science. I would also like to thank Dr. (honoris causa) Alexandra Morton for entrusting me with 20 years’ worth of her invaluable, irreplaceable, hard- won data on Pacific white-sided dolphins. Having spent 6 years working with these dolphins to continue the study Alexandra started, I have a new appreciation for the level of commitment that it took for launch it. Alexandra took the time to engage in fruitful discussions with me that furthered my understanding about the biology of the dolphins with which she has spent the past 25 years. I would like to thank Dr. Rob Williams for inspiring my study (by showing me my first Pacific white-sided dolphin) and encouraging me to always think bigger and set ambitious goals for my science. Rob also provided a research vessel, a base camp, a dog, and all the other resources needed to initiate the study, for which I am beyond grateful. Thank you to Paul Spong and Helena Symonds at Orcalab for sharing their data, their reports, their lab and home, their field assistants (especially, but not only, Emily Hague and Alyssa Rice), their knowledge and unwavering support. I am extraordinarily lucky to know and work with you. I would like to thank Marie Fournier, Christie McMillan, Melissa Boogaards, Nicole Koshure, Leila Fouda, and Alyssa Rice for their assistance with photo-matching and rising to the challenge of helping me turn tens of thousands of photographs into encounter histories. Javier Klaich has provided oceans of support, advice, and ideas throughout this process and I owe him mountains of gratitude. Thank you to Alex Zerbini and Julian Tyne for your discussions and advice. A big thanks to Doug Sandilands for database advice and support. Thanks also to Kate Blowers for Access insight and fresh bread in the field that kept me writing! Thank you to Marjolaine Caillat, Volker Deecke, Doug Gillespie, Vincent Janik, Christine Erbe, and Jamie Macaulay for advice on the acoustics analysis. Thank you Erin Cafferty for GIS advice. Thank you to Shane Gero for inspiring the social analysis and providing SOCPROG advice and ii support. I was extraordinarily lucky to work alongside an incredibly intelligent, warm, and supportive group of students at St Andrews. In particular, my office mates, Sanna Kuningas, Lindsay Wilson, Marina Costa, Diane Claridge, Salomé Dussán-Duque, Christian Ramp, Aaron Banks, Monica Arso-Civil, Inez Campbell, and Rob Williams were always available for advice and a chat. My cohort of students at St Andrews, and the entire team at SMRU and CREEM, are an extraordinary group of people to work with. Thank you to Don Willson for an unforgettable and productive expedition to Knight Inlet. And, thank you to James Willson for towing us when our boat died. Thank you to Alder Bay Resort for looking after our boat when it wasn’t dying. A huge thank you to the research, whalewatching, and conservation community of the North Island in British Columbia for sightings, reports, updates, and support, with special thanks to Bill Herbert, Wendy Thompson and Angela Smith. Thank you to Michael Moore, Frances Gulland, Stephen Raverty, Joe Gaydos, Ken Langelier, Antonio Fernandez, and Doug Sandilands for providing their expert opinion on the dolphin injury assessment. Thank you to Brad Hanson, Marilyn Dahlheim, Karen Hansen, Stan Hutchings, Jim Borrowman, Jack Springer, Gerry Henckel, Erin Rechsteiner, Alexandra Morton, Lisa Spaven, Jack Springer, Garry Henkel, Jared Towers, James Willson and Don Willson and others for providing information on killer whale on dolphins and Mridula Srinivasan for advice on putting this work in context. The MARK community was incredibly kind to me. Evan Cooch, Gary White, David Anderson, Javier Klaich and Ken Burnham gave great advice at the MARK workshops, and inspired the round of studies I would like to do next. Similarly, Bill Perrin, Barb Taylor, Jay Barlow, Melissa Soldevilla and Liz Henderson were very helpful in sharing information on Pacific white-sided dolphins in other parts of their range. Thanks to Denise Herzing, Randall Reeves iii and Erich Hoyt for big-picture advice. Thank you to Bob Lacy for advice on using the new version of Vortex. This project would not have been possible without the support of a small group of dedicated funders and supporters. Thank you to The SeaDoc Society for ‘going first’ and having confidence in this study.