A decade of marine mammal acoustical presence and habitat preference in the Bering Sea

Abstract

As Arctic seas rapidly change with increased ocean temperatures and decreased sea ice extent, traditional Arctic marine mammal distributions may be altered, and typically temperate marine mammal species may shift poleward. Extant and seasonal odontocete species on the continental shelves of the Bering and Chukchi Seas include killer whales (Orcinus orca), sperm whales (Physeter microcephalus), beluga whales (Delphiapterus leucas), harbor porpoises (Phocoena phocoena), and Dall’s porpoises (Phocoenoides dalli). Newly documented, typically temperate odontocete species include Risso’s dolphins (Grampus griseus) and Pacific white-sided dolphins (Lagenorhynchus obliquidens). Until recently, recording constraints limited sampling rates, preventing the acoustic detection of many of these high frequency-producing (> 22 kHz) species in the Arctic seas. Using one of the first long-term datasets to record frequencies up to 50 kHz in these waters, clicks, buzzes, and whistles have been detected, classified, and paired with environmental data to explore which variables best parameterize habitat preference. Typically temperate species were associated temporally with cold Bering Sea Climate Regimes in tandem with negative Pacific Decadal Oscillations. Typically Arctic species’ strongest explanatory variables for distribution were largely species and site specific. Regardless of species, however, the environmental cues (e.g. percent ice cover or zooplankton community structure) marine mammals use for locating viable habitat space are ones that will change as temperatures increase. This 10-year dataset documents the current state and tracks recent dynamics of odontocetes and their habitats along the Pacific Arctic Corridor to contribute to ongoing discussions about future Arctic conditions.