Congratulations to Dr. Kate Sprogis on her PhD completion on sex-specific behavioural ecology of bottlenose dolphins

Home / Latest News / Congratulations to Dr. Kate Sprogis on her PhD completion on sex-specific behavioural ecology of bottlenose dolphins
We’re pleased to announce that the Academic Council from Murdoch University have conferred Kate’s Ph.D. on the 19 August 2015, entitled:

Sex-specific patterns in abundance, home ranges and habitat use of Indo-Pacific bottlenose dolphins (Tursiops aduncus) in south-western Australia”.

Kate’s thesis can be accessed here. Kate will be graduating on 10 September 2015.

PhD Thesis Abstract:

This thesis explores sex-specific patterns in population abundance, demographic parameters, home range size and habitat use by Indo-Pacific bottlenose dolphins (Tursiops aduncus) off Bunbury, Western Australia. Photographic-identification data were collected year round between 2007-2013 through systematic boat-based surveys along pre-determined transect lines within a 540 km2 study area consisting of open coastal waters and sheltered waters. Chapter one provides background and outlines the specific aims of the thesis. In Chapter two, I estimated sex-specific population parameters of abundance, movement and survival using Pollock’s Robust Design. The estimated number of dolphins in the study area was seasonally dependent, and for identifiable adult males ranged from 24 (± 5.73 SE) to 50 (± 5.48 SE) and for identifiable adult females from 28 (± 2.99 SE) to 60 (± 2.38 SE). The lowest abundance estimates coincided with both the strongest phase of an El Niño event and an unparalleled peak in dolphins temporarily emigrating out of the study area. In Chapter three, I explored sex-specific differences in home range size using a new approach for kernel density estimation that accounts for physical barriers to movements. A Bayesian mixture model indicated a 99% probability that adult males have larger home ranges than females (adult males 27-187 km2 and adult females 20-133 km2), and that dolphins sighted primarily in open waters have larger home ranges than those residing in sheltered waters. In Chapter four, I used kernel density analyses and generalised additive models to explore seasonal space use and elucidate biotic and abiotic variables that influence seasonal habitat use differences between the sexes. I documented differing variables influencing habitat use between sexes and seasons, high use areas within the bay during summer, movements offshore and a concentration of females in the estuary during winter. I discuss factors that may explain the documented sex-specific differences in abundance, demographic parameters, home ranges and habitat use, including intrinsic (social dynamics, dolphin biology) and extrinsic (prey availability, predation risk, environmental variability) factors. My research emphasises the value and importance of a sex-specific approach when studying the behavioural ecology of coastal delphinids.

A dolphin leaping with the town of Bunbury, Western Australia, in the background.

A dolphin leaping with the town of Bunbury, Western Australia, in the background.

Publications arising from Kate’s work:

Sprogis, K. R., H. C. Raudino, R. Rankin, C. D. MacLeod, L. Bejder. In Press. Home range size of adult Indo-Pacific bottlenose dolphins (Tursiops aduncus) in a coastal and estuarine system is habitat and sex-specific. Marine Mammal Science. DOI: 10.1111/mms.12260

Sprogis, K. R., K. Pollock, H. C. Raudino, S. Allen, A. Kopps, O. Manlik, J. Tyne, L. Bejder. In prep. Sex-specific patterns in abundance, temporary emigration and survival of Indo-Pacific bottlenose dolphins (Tursiops aduncus) in coastal and estuarine waters. Tentative title and author list.

Sprogis, K. R., H. Kobryn, H. C. Raudino, R. Wells, L. Bejder. In prep. Seasonal and sex-specific patterns in fine-scale habitat use of Indo-Pacific bottlenose (Tursiops aduncus) dolphins. Tentative title and author list.

Sprogis, K. R., F. Christiansen, K. Pollock, L. Bejder. In prep. Impacts of El Niño Southern Oscillation on the abundance and movements of an apex predator. Tentative title and author list.

Acknowledgements:

Since 2011, it has been such an amazing journey with so much to see in Bunbury, with great people and good times. I would like to thank my supervisors; Lars Bejder, Ken Pollock, Halina Kobryn and Randall Wells. I would also like to thank the Bunbury Dolphin Discovery Centre staff and volunteers, Colin MacLeod, Pat Halpin and Dave Johnston at Duke University, MUCRU lab mates and my family and friends.

My fieldwork could not have been able or been as enjoyable without the enthusiastic help from my assistants and intern students. Thank you for your assistance in the field, countless hours of data entry and photo-identification in the Bunbury office. Thank you to: Stephie Loeber, Tamara Organ, Megan Franklin, Adam Wilson, Cameron Hookey, Ariana Sauret, Niels Bracke, Natshja de Couck, Sarah MacLeod, Catharina Vendl, Catherine Derieux, Riona Howard, Thekla Boess, Anita Byrne, Eloise Ashworth, Rene Bryskov, Victoria Hope, Grainne Ryan, Katrina MacIver, Elena Holland and Elisa Chillingsworth. A special thank you to my intern students (masters and under-grad) who were a pleasure to work with. Thank you for being patient, independent, and for producing such great reports: Eileen Hesse, Sina Sibler, Isabelle Ciomber, Inge de Boer, Wils Alpern, Welmoed Wehkamp, Anne Jacobs, Philippine Chambault, Hannah Kriesell, Charlotte Moura, Rebecca Shoer and Kim ter Haar.

Some of Kate’s volunteers and interns assisting for the project in Bunbury- Thank you!!! ☺

Some of Kate’s volunteers and interns assisting the project in Bunbury- Thank you!!! ☺

Project Funding:

This research was made possible through the financial commitment and foresight of local government, community and industry partners for the South West Marine Research Program. These organisations should be commended for their support of science-informed management. I thank the funding partners; BHP Billiton Worsley Alumina, Bunbury Dolphin Discovery Centre, Bunbury Port Authority, the City of Bunbury, Cristal Mining, the Western Australian Department of Parks and Wildlife, Iluka, Millard Marine, Naturaliste Charters, Newmont Boddington Gold, South West Development Commission and WA Plantation Resources.

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