Divergence of Hawaiian false killer whales

July 24, 2015

Principal Investigator: Karen Martien, Marine Mammal Genetics Program

False killer whale

False killer whales (Pseudorca crassidens) are large Delphinids typically found in deep water far offshore.  However, in the Hawaiian Archipelago, there are two resident island-associated populations of false killer whales, one in the waters around the main Hawaiian Islands (MHI) and one in the waters around the Northwestern Hawaiian Islands (NWHI).  The MHI population was recently listed as Endangered under the U. S. Enangered Species Act.

We are using a variety genetic markers and methods to study Hawaiian false killer whales.  We’ve recently completed a project using mitochondrial control region sequences and microsatellite genotypes to examine patterns of divergence among the two island-associated populations and offshore animals from the central and eastern North Pacific.  Our results suggest a complex evolutionary history for the island-associated populations, with both of them likely sharing a common colonization history, but with limited contemporary gene flow.

We are also using microsatellite genotypes to examine social structure and mating patterns with the MHI population.  Photo-identification studies conducted by Cascadia Research Collective revealed the existence of three distinct social groups within that population.  We are using parentage analysis to determine whether or not animals stay in their natal social group and whether mating primarily occurs between individuals from the same social group or different social groups.

Finally, we have begun a project to use full mitochondrial genome sequences and large numbers of SNP markers to estimate divergence times between false killer whales from the Pacific and Atlantic Oceans, as well as between the Hawaiian island-associated populations and the rest of the Pacific.  The result of the study could lead to the identification of separate subspecies within the species.

Learn more:

Cascadia Research Collective's false killer whale page.

Martien, K.K., S.J. Chivers, R.W. Baird, F.I. Archer, A.M. Gorgone, B.L. Hancock-Hanser, D. Mattila, D.J. McSweeney, E.M. Oleson, C. Palmer, V.L. Pease, K.M. Robertson, G.S. Schorr, M.B. Schultz, D.L. Webster, B.L. Taylor.  2014.  Nuclear and mitochondrial patterns of population structure in North Pacific false killer whales (Pseudorca crassidens).  Journal of Heredity.  105: 611-626.

Baird, R.W., E.M. Oleson, J. Barlow, A.D. Ligon, A.M. Gorgone, S.D. Mahaffy.  2013  Evidence of an island-associated population of false killer whales (Pseudorca crassidens) in the Northwestern Hawaiian Islands.  Pacific Science 67.

Baird, R.W., M.B. Hanson, G.S. Schorr, D.L. Webster, A.M. Gorgone, S.D. Mahaffy, D.M. Holzer, E.M. Oleson, R.D. Andrews. 2012. Range and primary habits of Hawaiian insular false killer whales: informing determination of critical habitat.  Endangered Species Research 18:47-61.

Baird, R.W. 2009. A review of false killer whales in Hawaiian waters: biology, status, and risk factors. Report prepared for the U.S. Marine Mammal Commision under Order No. E40475499. 49pp.

Baird, R.W., A.M. Gorgone, D.J. McSweeney, D.L. Webster, D.R. Salden, M.H. Deakos, A.D. Ligon, G.S. Schorr, J. Barlow and S.D. Mahaffy. 2008. False killer whales (Pseudorca crassidens) around the main Hawaiian Islands: long-term site fidelity, inter-island movements, and association patterns. Marine Mammal Science 24:591-612.

Chivers, S.J., R.W. Baird, D.J. McSweeney, D.L. Webster, N.M. Hedrick and J.C. Salinas. 2007. Genetic variation and evidence for population structure in eastern North Pacific false killer whales (Pseudorca crassidens). Canadian Journal of Zoology 85:783-794.

Last modified: 10/4/2016