The Chukchi and Beaufort seas are undergoing rapid climate change and increased human activity.
Conservation efforts for upper trophic level predators such as seabirds and marine mammals require
information on species’ distributions and identification of important marine areas. Here we describe
broad-scale distributions of seabirds and marine mammals. We examined spatial patterns of relative
abundance of seabirds and marine mammals in the eastern Chukchi and western Beaufort seas during
summer (15 June–31 August) and fall (1 September–20 November) from 2007 to 2012. We summarized
49,206 km of shipboard surveys for seabirds and 183,157 km of aerial surveys for marine mammals into a
grid of 40-km  40-km cells. We used Getis-Ord Gi⁄ hotspot analysis to test for cells with higher relative
abundance than expected when compared to all cells within the study area. We identified cells representing
single species and taxonomic group hotspots, cells representing hotspots for multiple species, and
cells representing hotspots for both seabirds and marine mammals. The locations of hotspots varied
among species but often were located near underwater canyons or over continental shelf features and
slopes. Hotspots for seabirds, walrus, and gray whales occurred primarily in the Chukchi Sea. Hotspots
for bowhead whales and other pinnipeds (i.e., seals) occurred near Barrow Canyon and along the
Beaufort Sea shelf and slope. Hotspots for belugas occurred in both the Chukchi and Beaufort seas.
There were three hotspots shared by both seabirds and marine mammals in summer: off Wainwright
in the eastern Chukchi Sea, south of Hanna Shoal, and at the mouth of Barrow Canyon. In fall, the only
identified shared hotspot occurred at the mouth of Barrow Canyon. Shared hotspots are characterized
by strong fronts caused by upwelling and currents, and these areas can have high densities of euphausiids
in summer and fall. Due to the high relative abundance of animals and diversity of taxa, these sites are
clearly important areas of congregation for seabirds and marine mammals that should be prioritized in
the development of management and conservation plans.

Kuletz, K. J., M. C. Ferguson, B. Hurley, A. E. Gall, E. A. Labunski, and T. C. Morgan. 2015. Seasonal spatial patterns in seabird and marine mammal distribution in the eastern Chukchi and western Beaufort seas: identifying biologically important pelagic areas. Progress in Oceanography 136: 175–200.  <>

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