A western North Pacific gray whale spyhops off Sakhalin Is., Russia. This project will help characterize potential genetic differences between PCFG and other gray whale populations in the North Pacific. Image credit: Craig Hayslip.

The gray whales we call “summer residents” along the Oregon coast are part of a small population of around 230 animals (Calambokidis et al. 2020) known as the “Pacific Coast Feeding Group” (PCFG). During winter months these PCFG gray whales migrate south to the warm lagoons in Baja California, Mexico, to breed and calve. But in summer months they end their northbound migration in the Pacific Northwest, where they feed in shallow waters from northern California to Southeast Alaska (Lagerquist et al. 2019), while the larger population, known as Eastern North Pacific gray whales and numbering about 20,000 animals (Stewart and Weller 2021), continues their migration to the Arctic. Yet a third group, of around 200 animals and known as the Western North Pacific population, feeds off the Russian coast in the Sea of Okhotsk (Mate et al. 2015). One of the main outstanding questions about PCFG gray whales is whether their population is genetically different and demographically independent from both the Eastern and Western Pacific gray whale populations, which could warrant separate management status (International Whaling Commission 2012, Weller et al. 2013).

Between 2009 and 2013, we deployed satellite tags on 33 PCFG gray whales off central Oregon and northern California to track their movements over long periods of time. The tags provided a wealth of new information about the movements of PCFG whales (Mate 2013, Mate et al. 2014, Lagerquist et al. 2019). For 25 of the tagged animals we also obtained a small sample of skin and blubber using a biopsy dart for various analyses. In collaboration with the Cetacean Conservation and Genomics Lab (CCGL), the goal of this project is to generate complete genetic profiles for these samples, consisting of: (a) sex identification, (b) mitochondrial DNA haplotype, and (c) microsatellites for individual identification and parentage analysis (maternity or paternity) (e.g., Lang et al. 2022). Combined with tagging data, we can refine the population distinctiveness question and also ask, for example, whether genetics reflect how different individuals move and where they spend most of their time.

The DNA register for PCFG gray whales, initially for the 25 tagging samples, is anticipated to grow and become an important resource to the community as samples continue to be submitted to CCGL. The DNA register will be available for use by the scientific community, particularly within the PCFG Consortium. Ultimately, this new knowledge will provide another line of evidence for refining our understanding and possible designation of this subpopulation as a differentiated stock, which could have significant management and conservation implications.

Funding

The tissue samples were collected during tagging activities sponsored by ONR, IWC, IUCN, Navy Fleet Command, Exxon Neftgas, and private donors to the Marine Mammal Institute Endowment. This project is funded by the Marine Mammal Institute's Oregon Gray Whale License Plate Program. We deeply appreciate the support of the Oregonians who purchased or renewed their Coastal Playground license plate!

References

Calambokidis, J., J. Laake, and A. Perez. 2020. Updated analysis of abundance and population structure of seasonal gray whales in the Pacific Northwest, 1996-2017. Paper SC/A17/GW/05SC/68B/ASI01 presented to the International Whaling Commission Scientific Committee Annual Meeting, 12–24 May 2020, virtual. 73pp.

International Whaling Commission. 2012. Report of the Scientific Committee. Journal of Cetacean Research and Management (Suppl.) 13.

Lagerquist, B.A., D.M. Palacios, M.H. Winsor, L.M. Irvine, T.M. Follett, and B.R. Mate. 2019. Feeding home ranges of Pacific Coast Feeding Group gray whales. Journal of Wildlife Management 83(4):925-937. https://doi.org/10.1002/jwmg.21642.

Lang, A. R., Weller, D. W., Burdin, A. M., Robertson, K., Sychenko, O., Urbán, J., Martínez-Aguilar, S., Pease, V. L., LeDuc, R. G., Litovka, D. I., Burkanov, V. N., & Brownell, R. L. 2022. Population structure of North Pacific gray whales in light of trans-Pacific movements. Marine Mammal Science 38(2):433-468. https://doi.org/10.1111/mms.12875.

Mate, B. 2013. Offshore Gray Whale Satellite Tagging in the Pacific Northwest. Prepared for Commander, U.S. Pacific Fleet, Pearl Harbor, Hawaii. Submitted to Naval Facilities Engineering Command Northwest (NAVFAC NW), Silverdale, WA 98315-1101, under Contract # N62470-10-D-3011, issued to HDR Inc., San Diego, California 92123. 18 June 2013.

Mate, B. R., Ilyashenko, V. Y., Bradford, A. L., Vertyankin, V. V., Tsidulko, G. A., Rozhnov, V. V., & Irvine, L. M. 2015. Critically endangered western gray whales migrate to the eastern North Pacific. Biology Letters 11(4), 20150071. https://doi.org/10.1098/rsbl.2015.0071.

Mate, B., L. Irvine, and T. Follett. 2014. Offshore Gray Whale Satellite Tagging in the Northwest Training Range Complex (NWTRC). Prepared for Commander, U.S. Pacific Fleet, Pearl Harbor, Hawaii. Submitted to Naval Facilities Engineering Command Northwest (NAVFAC NW), Silverdale, WA 98315-1101, under Contract # N62470-10-D-3011, issued to HDR Inc., San Diego, California 92123. June 2014.

Stewart, J.D. and D.W. Weller. 2021. Abundance of eastern North Pacific gray whales 2019/2020. U.S. Department of Commerce, NOAA Technical Memorandum NMFS-SWFSC-639. https://doi.org/10.25923/bmam-pe91.

Weller, D.W., S. Bettridge, R.L. Brownell Jr., J.L. Laake, J.E. Moore, P.E. Rosel, B.L. Taylor, and P.R. Wade. 2013. Report of the National Marine Fisheries Service Gray Whale Stock Identification Workshop. U.S. Dep. Commer., NOAA Tech. Memo. NOAA-TM-NMFS-SWFSC-507. https://repository.library.noaa.gov/view/noaa/4463.

For further information please contact project PIs Daniel Palacios and Scott Baker.

Background image credit: Craig Hayslip