Cetacean Habitat Selection in the Alaskan Arctic during Summer and Autumn

Abstract

Ten years (1982-91) of sighting data from aerial surveys offshore of northern Alaska were analyzed to investigate seasonal variability in cetacean habitat selection. Distinct habitats were described for bowhead whales ( Balaena mysticetus ), white whales ( Delphinapterus leucas ), and gray whales ( Eschrichtius robustus ) on the basis of habitat selection ratios calculated for bathymetric and ice cover regimes. In summer, bowheads selected continental slope waters and moderate ice conditions; white whales selected slope and basin waters and moderate to heavy ice conditions; and gray whales selected coastal/shoal waters and open water. In autumn, bowheads selected inner shelf waters and light ice conditions; white whales selected outer shelf and slope waters and moderate to heavy ice; and gray whales selected coastal and shoal/trough habitats in light ice and open water. Habitat differences among species were significant in both seasons (ANOVA F > 28, p 0.35). White whale depth habitat was significantly different between seasons ( p < 0.00002), but ice cover habitat was not ( p < 0.08).