Emerging patterns of species richness, diversity, population density, and distribution in the skates of Alaska

The species richness, diversity, relative density, and distribution of skates throughout Alaskan waters in the Bearing Sea, Aleutian Islands, and Gulf of Alaska were examined. The eastern Bearing Sea shelf survey was conducted annually. Bottom area swept was calculated for each haul by multiplying the distance fished by the mean net spread. The Bearing Sea shelf accounted for significantly more trawling effort than any of the other regions. Thirteen of the 14 species of skates known from Alaskan waters were encountered in bottom-trawl surveys. The number of individual skates captured in a single haul ranged from 0 to 833, which yielded aggregate density. Skates were encountered throughout the entire geographic and bathymetric range of the survey area in over 87% of the hauls conducted in the region.