Food and Distribution of Lake Whitefish in Lac la Ronge, Saskatchewan

Abstract

Lake whitefish, Coregonus clupeaformis (Mitchill), of Lac la Ronge, Saskatchewan, were studied from 1948 to 1954. Stomach contents of 1,606 fish from the main lake and 607 from Hunter Bay were analyzed. In the main lake from 40 to 60 percent of the food consisted of chironomid larvae with sphaeriids and caddisfly larvae being other important items. In Hunter Bay amphipods were the chief food and chironomid larvae and sphaeriids shared second place. Abundance and availability of food organisms seemed to determine the type of food utilized. In the early summer whitefish were widely scattered in Lac la Ronge. As the surface water warmed, the fish moved into deeper water apparently responding to temperature changes. In the main lake during July, August, and early September they were concentrated between the depths of 15 and 27 meters. Water temperature ranged from 11° to 14° C. In Hunter Bay during midsummer fish were abundant from 15 to 35 meters where temperatures were usually 8° to 11° C. Whitefish were more active during the night than during the day.