Feeding Habits of the Dolly Varden, Salvelinus malma (Walbaum), at Chignik, Alaska

Abstract

Stomach contents of 5,050 Dolly Varden were examined during the summers of 1955 and 1956 to determine the extent of predation by this species upon young sockeye (red) salmon (Oncorbyncbus nerka). Of 5,050 stomachs examined, 2,667 (52.8 percent) were empty. Of those containing food, 73.2 percent contained insects, and 9.0 percent sockeye salmon. In all, the 214 Dolly Varden which had been feeding on young sockeye had consumed 649 salmon for an average of 0.1 sockeye for all Dolly Varden examined.

Predation was greatest in rapid water immediately below the outlet of Chignik Lake and here 31.1 percent of the Dolly Varden stomachs contained sockeyes. Greatest predation occurs where swift current and natural obstacles restricted movement of young salmon. Dolly Varden of intermediate size (between 15 and 35 centimeters) were the most destructive to young sockeye salmon. There was a direct relationship between size of trout and proportion with food; small fish more often had food in their stomachs. It appears that Dolly Varden feed more actively during their summer stay in salt water than during their winter residence in the lakes. It seems unlikely that the Dolly Varden is a serious predator upon the salmon in the Chignik Lake drainage.