Characterization of Diet using Stomach Contents and Multivariate Statistics of four Beaufort Sea Eelpout Species

Eelpouts of the genus Lycodes are a group of demersal fish commonly found in the U.S. Beaufort Sea. They are relatively numerous, having composed a significant proportion of fish catches during trawl surveys, and they are consumed by marine mammals and birds. Eelpouts themselves may also potentially feed on, or compete for resources with, other fish species. Currently, however, their exact role in the Arctic food web is still poorly understood. Percent number (%N) and percent weight (%W) were used to describe diet, and multivariate techniques were used to look for patterns across environmental (depth and longitude) and biological (length) gradients. Fish were collected in August and September of 2012 and 2014 as part of the U.S.-Canada Transboundary cruises. Stomachs from four eelpout species were examined: Adolf’s Eelpout Lycodes adolfi, Canadian Eelpout L. polaris, Archers Eelpout L. sagittarius, and Longear Eelpout L. seminudus. Polychaetes, benthic amphipods, brittle stars, and harpacticoid copepods composed a large part of the observed diet for all four Lycodes species, but proportions differed by species. Intraspecific similarity was low, suggesting these fish have diverse diets even among individuals of the same species. Fish total length was found to be correlated with diet composition for all fish species examined except L. seminudus. Longitude and depth were found to be correlated with diet for L. sagittarius. Identifying prey and factors influencing diet are initial steps towards characterizing the ecological role of this fish genus in the U.S. Arctic food web. Ecological information on abundant fish species is needed for the development of ecosystem-based management practices. Establishing a benchmark for this group is important for understanding their current and future role in the rapidly changing Arctic food web.