Freshwater Food Habits of "Salvelinus malma" (Walbaum) on Amchitka Island, Alaska

Abstract

Freshwater Food Habits of SaZveZinus maZma (Wa1baum) On Amchitka Island, Alaska by John F. Palmisano, Master of Science Utah State University, 1971 Major Professor: Dr. William T. Helm Department: Wildlife Resources ix Stomach contents of 3,672 Dolly Varden char collected from September 1967 to November 1968 were examined to determine the food habits of this species. Of these, 3,100 (86%) had food in their stomachs. Aquatic invertebrates (Insecta and Crustacea) comprised over 90% of the diet. Food habits varied with habitat. Aquatic insects were most important in the diet of stream fish while aquatic insects and crustaceans were most important in the diet of lake fish. Food habits of lake fish were re1ated to lake bottom type and access to the sea. Fish in landlocked lakes fed primarily on aquatic insects, fish, and fish eggs. In lakes with access to the sea, crustaceans, followed by aquatic insects, were the major food items in those with firm bottoms adjacent to shore while aquatic insects, followed by crustaceans, were the major food items in those with muck bottoms adjacent to shore. As fish size increased, feeding activity decreased and aquatic insects became less important in the diet while crustaceans and fish became more important. During summer, feeding activity was highest for lake fish while it was highest during autumn and summer for stream fish. Aquatic insects were the dominant food item in summer while crustaceans and fish were dominant