January 19, 2011
Principal Investigator: Aimee Lang, Marine Mammal Genetics Group
Blue whales (Balaenoptera musculus) are currently listed globally as endangered. However, abundance and trend data on blue whales in parts of the North Pacific suggest that down- or de-listing may be appropriate, highlighting the need to better resolve subspecific taxonomy and population structure in this species to permit such considerations. Currently three subspecies are recognized, including B. m. musculus in the North Atlantic and North Pacific; B. m. intermedia, which is found in Antarctic waters during summer months; and B. m. brevicauda, the pygmy form, which is generally distributed in the sub-Antarctic waters of the Indo-Pacific Ocean and southeastern Atlantic Ocean. Previous research (LeDuc et al. 2007) supported genetic distinctions between the two named subspecies of blue whales in the Southern Hemisphere and also suggested that an additional subspecies designation might be needed to describe Southern Hemisphere blue whales.
Ongoing genetic work is focused on integrating mtDNA control region and microsatellite data generated from blue whale samples collected in the north Pacific and eastern tropical Pacific with that previously published for Southern Hemisphere blue whales (LeDuc et al. 2007). In addition, Next Generation Sequencing methods are being used to generate whole mitochondrial genome sequences as well as sequences for approximately 50 nuclear loci from ~300 globally-distributed blue whale samples. Data generated in these projects will be utilized to provide insight into the subspecific taxonomy of blue whales, with a focus on evaluating the subspecific status of blue whales in the eastern north Pacific.
LeDuc, R.G., A.E. Dizon, L.A. Pastene, H. Kato, S. Nishiwaki, C.A. LeDuc, and R.L. Brownell. 2007. Patterns of genetic variation in Southern Hemisphere blue whales and the use fo assignment test to detect mixing on the feeding grounds. Journal of Cetacean Research and Management 9:73-80.