Monitoring bowhead whale occurrence in the Bering Sea using passive acoustics

Mark Baumgartner and H. Carter Esch, Biology

Abstract

The Arctic is experiencing rapid shifts in climate, yielding changes in ice and trophic
ecosystem dynamics. In particular, the Bering Sea ecosystem is closely tied to sea ice dynamics,
making it disproportionately susceptible to decreased environmental stability. Arctic marine
mammals utilize the Bering Sea as seasonal habitat, carrying out important life history events
related to the cryosphere. Increasingly ice-free periods and intensifying anthropogenic activities
in the Arctic will challenge the adaptability of these species; therefore, there is an urgent need to
characterize current habitat use and identify critical habitat for future protection. Monitoring of
marine mammals wintering in the Bering Sea is virtually impossible using traditional visual
survey methods. We propose to analyze acoustic and oceanographic data collected concurrently
at 2 locations in the Bering Sea from 2008-2010 to document seasonal occurrence of bowhead
whales, resolve migration timing, and help to characterize critical habitat (e.g., breeding
grounds). Documentation of the context and extent of bowhead whale occurrence in specific
regions like southwest of St. Lawrence Island polynya and southeast of St. Matthew Island
(further east than is currently acknowledged as wintertime habitat for bowheads) will inform (1)
dynamic ecosystem models seeking to understand habitat utilization patterns and (2) agencies
charged with managing Arctic marine mammals impacted by global climate change.