Right whale distribution in the Bering Sea revisited: A fresh look.

Abstract

The North Pacific right whale (Eubalaena japonica) is one of the most endangered baleen whales in the world, with current abundance estimates of fewer than 40 individuals. As such, it has been the focus of intensive population monitoring studies. Long‐term passive acoustic monitoring is a useful tool for assessing distribution, habitat use, and population status of marine mammals. For Bering Sea right whales, past analyses of distribution were based on their stereotyped upsweep call. Results from sonobuoy recordings made during the 2008 and 2009 southeastern Bering Sea right whale cruises, however, found gunshot calls to be much more common. To assess whether inclusion of gunshot call detections will change our understanding of the spatial and temporal distribution of North Pacific right whales, we examined four years (2006–2009) of long‐term recordings made by the National Marine Mammal Laboratory and the Pacific Marine Environmental Laboratory at six different locations on the Bering Sea shelf. A comparison of the results using upsweeps, gunshots, and a combination of both will be presented. [Work supported by an Inter‐Agency Agreement from the Minerals Management Service.]