North Pacific Right Whale Ecology

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North Pacific right whale (Eubalaena japonica).

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The WHOI team aboard the F/V Aquila in the Bering Sea during the summer of 2009 (left to right: Mark Baumgartner, Sarah Mussoline, Carter Esch, and Nadine Lysiak).

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The 160 foot crab boat, F/V Ocean Olympic, served as our oceanographic vessel for the 2008 field season.

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Carter Esch and Mark Baumgartner aboard the F/V Ocean Olympic after deploying a RATS buoy.


Principal Investigator:  Mark Baumgartner (WHOI Biology)

Collaborators: Alex Zerbini, Catherine Berchok, Phil Clapham (NOAA National Marine Mammal Laboratory)

The eastern stock of North Pacific right whales (Eubalaena japonica) numbers fewer than 100 animals, and is arguably the most critically endangered large whale species.  Whaling records indicate that right whales were once abundant throughout the eastern North Pacific and Bering Sea during the summer months.  Right whales were hunted with such intensity during the 19th and early 20th centuries that they were afforded international protection from hunting in 1935 owing to their low population size.  The right whale population was likely growing by 1960, but large illegal catches by Soviet whalers during the 1960’s in the eastern North Pacific and Bering Sea probably crippled recovery.  The right whales in the eastern North Pacific are only a remnant of the former population, and they may not fully occupy the same range they did two centuries ago.  While the importance of other historic habitats in the eastern North Pacific remains unresolved, modern sightings of right whales confirm that the southeastern Bering Sea remains a critical habitat for North Pacific right whales.

The climate of the Bering Sea is changing, which has the potential to substantially alter the ecosystem and the availability of prey for right whales.  Right whales are filter feeders and are very limited in the number and type of prey they can consume.  Their slow swimming speed precludes capture of small fish and very large euphausiids preyed upon by other baleen whales, such as humpback and fin whales.  Instead, right whales feed primarily on copepods and small euphausiids.  Recent zooplankton net sampling near right whales in the southeastern Bering Sea suggests that the copepod Calanus marshallae may be the right whale’s primary prey there.  High summertime C. marshallae abundance is related to cold winter conditions and extensive sea ice coverage in the southern Bering Sea.  The decreased southerly penetration and reduced persistence of sea ice in the southeastern Bering Sea in recent years has been accompanied by a decrease in summer zooplankton biomass.  These changes may have profound effects on the recovery of the North Pacific right whale.

During the summers of 2008 and 2009, we participated in collaborative research with the NOAA National Marine Mammal Laboratory to study the distribution, behavior, and ecology of the North Pacific right whale in the southeastern Bering Sea.  Our objectives were to (1) study the foraging ecology of right whales by attaching instruments to the whales and intensively sampling both oceanographic conditions and prey distribution in proximity to the tagged whales, (2) conduct broadscale oceanographic sampling to understand the processes that lead to the formation of prey aggregations, (3) collect zooplankton samples to identify the primary prey of the whales and to characterize the regional distribution, abundance, and community composition of zooplankton, and (4) collect acoustic recordings and conduct repeated oceanographic and prey sampling in proximity to whales over time scales of tens of hours to assess relationships between right whale calling activity and both oceanographic conditions and the vertical migration behavior of their prey.

Support for this project provided by the U.S. Minerals Management Service.

Publications and Presentations
Esch, H.C., M.F. Baumgartner, C. Berchok, and A.N. Zerbini. 2009. Fine-scale temporal variability of North Pacific right whale call production. 18th Biennial Conference on the Biology of Marine Mammals. The Society for Marine Mammalogy. Québec, Canada. October 12-16, 2009.

Baumgartner, M.F., H.C. Esch, and A.N. Zerbini. 2009. Association between North Pacific right whales and a subsurface front in the southeastern Bering Sea. 18th Biennial Conference on the Biology of Marine Mammals. The Society for Marine Mammalogy. Québec, Canada. October 12-16, 2009.



 

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Last updated April 19, 2011
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