The Food of the Pike, Esox lucius, in Heming Lake, Manitoba

Abstract

The stomach contents of 29,477 northern pike (Esox lucius) captured mainly in gill nets at Heming Lake, Manitoba, between 1950 and 1962 were examined. The food consisted almost exclusively of fish: trout-perch (Percopsis omiscomaycus) and yellow perch (Perca flavescens). Other fish included common suckers (Catostomus commersoni), spottail shiners (Notropis hudsonius), sticklebacks (Eucalia inconstans and Pungitius pungitius), pike, burbot (Lota lota), whitefish (Coregonus clupeaformis), tullibee (Leucichthys sp.), yellow walleye (Stizostedion vitreum), cottid (Cottus cognatus), and darters (Etheostoma nigrum). Among invertebrates were crayfish, mayflies, dragonflies, caddisflies, and leeches. Ducks, small mammals, and frogs formed an insignificant part of the diet. Seasonal variation in food content and annual variation in the degree of feeding were evident. Trout-perch were important as food items in May and June, the spottail shiner in July, the yellow perch in August and September, and stickleback between October and March. Coregonine fishes, important in the life-cycle of Triaenophorus crassus but of minor importance as pike food, occurred in higher concentrations in October. There appeared to be annual differences in the degree of feeding, possibly related to differences in temperature. The frequency of empty stomachs from pike caught by angling and in gill nets was approximately the same. No obvious differences were noted in feeding habits of male and female pike, but there were some minor differences in the food of pike from shallow and deeper water habitats. Over an 11-year period of intensive fishing, there did not appear to be any unusual changes in the food habits of pike. The size of the prey is related to the size of the pike. There is a marked increase in the number of small perch, trout-perch, and spottail shiners consumed by pike of increasing size. The possible effects of the predator (pike) on other prey species is discussed. Relative abundance and seasonal availability appeared to determine the incidence of prey consumed. The reduction in the average size of the pike appears to have had some effect on the survival of other species of fish.