Arctic | Ecosystem Perspectives
Bio-physical drivers of bowhead whale distribution on the Alaskan Beaufort Shelf during a period of rapid environmental change Presenter: Stephen Okkonen , srokkonen@alaska.edu, University of Alaska Fairbanks Carin Asjian , cashjian@whoi.edu, Woods Hole Oceanographic Institution
Robert Campbell , rgcampbell@uri.edu, University of Rhode Island Kate Stafford , kate.stafford@oregonstate.edu, Oregon State University Mei Sato , msato@whoi.edu, Woods Hole Oceanographic Institution Phil Alatalo , palatalo@whoi.edu, Woods Hole Oceanographic Institution Hannah Sawyer , Hannah.Sawyer@oregonstate.edu, Oregon State University
The second field season of a three-year BOEM-funded study was undertaken in late summer 2022 to assess the influence of recent environmental changes on bowhead whale distributions and migration patterns in the southern Beaufort and northeast Chukchi Seas. This study employed boat-based surveys of hydrography and zooplankton, analyses of zooplankton morphometrics and genetics, and moored instruments to monitor water masses, currents, zooplankton presence and bowhead whale vocalizations at shelf and slope locations within our Beaufort-Chukchi study area. Preliminary analyses of 2022 field data showed a ~10-15 m thick surface sea ice meltwater layer (S < 30) was present along sentinel lines near Prudhoe Bay and Utqiaġvik. The dominant life stages of net-caught krill were juveniles/adults with very few furcilia stages present; a result consistent with the documented relationship between late-summer meltwater in Barrow Canyon and older life stage krill. The greatest numbers of net-caught krill occurred in mid-Barrow Canyon and at the southern half of the WDD depression; locations at which towed echosounder returns at 200 kHz indicated elevated zooplankton numbers. Bowhead whales were observed in shelf waters east of Utqiaġvik, as expected, following the relaxation of upwelling winds.
Alaska Marine Science Symposium 2023 174
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