Research

I am interested in the conservation of small populations, inter- and intra-specific variation in animal social systems, mechanisms of sympatric and parapatric speciation, the effects of competition and predation on population structure, and mechanisms and evolutionary consequences of cultural transmission in animals.

My own research is focused on a complex of sympatric and parapatric populations of killer whales off the west coast of British Columbia and Alaska.  The complex consists of at least three genetically distinct population assemblages.  The resident assemblage contains at least four parapatric populations, all of which prey on fish.  The transient assemblage also contains at least four populations, all of which prey on marine mammals.  The offshore assemblage has only one known population and is believed to feed primarily on fish and squid.  Comparison of the three population assemblages provides great opportunities for examining how ecology shapes the cultural evolution of social systems and social behaviours.

With a group of colleagues from Alaska, British Columbia, and France, I use custom-designed pneumatic darts to collect skin biopsies from photo-identified killer whales. Key findings based on the analysis of mitochondrial and nuclear (microsatellite) DNA from these samples are as follows: (1) residents and transients are discrete populations that are sufficiently genetically isolated to speciate sympatrically; (2) since the divergence of resident and transient lineages, each divided by fission into at least three genetically differentiated parapatric subpopulations; (3) acoustic repertoire similarity and relatedness of resident pods are strongly correlated, implying that new pods also arise by fission rather than by the coalescence of emigrants; (4) matings rarely if ever occur within resident pods, but instead occur during temporary associations between pods; (5) most matings occur between pods from different acoustic clans from the same subpopulation (an acoustic clan is a group of pods with similar vocal dialects); and (6) this mating pattern maintains low inbreeding levels in relation to the size of resident subpopulations.

I am actively involved in field studies in Western Alaska and British Columbia in the summer months.  When not in the field, I normally spend four days per week at the Vancouver Aquarium where my time is divided between analysis, writing, and administration, and one day per week at UBC, where I conduct molecular analyses in the Genetic Data Centre, with the assistance of Allyson Miscampbell and Hesther Yueh and the advice and support of lab director Carol Ritland. Two programs not directly connected to my own research that run out of my lab at the Aquarium are the BC Cetacean Sightings Network (coordinated by Doug Sandilands and Alana Phillips) and the BC Wild Killer Whale Adoption Program (run by Judy McVeigh).

I presently co-supervise three graduate students.