The feeding pattern and daily ration of a top carnivore, the northern pike (Esox lucius)

Abstract

Food habits, digestive rates, and daily ration were determined for 1290 northern pike (Esox lucius) collected from Lac Ste. Anne, Alberta. The data were used to develop a model for quantifying the daily ration of a top carnivore; the basic feature was that feeding time was short relative to time between meals. Pike diet included mainly perch (Perca flavescens), spottail shiners (Notropis hudsonius), burbot (Lota lota), and white suckers (Catostomus commersoni), in order by numerical importance. Caloric intake by pike depended mainly on perch, suckers, and burbot, in that order; the difference between the two rankings was due to differences in the size of individuals eaten. Gastric evacuation rate (determined by controlled experiment) was 48 h in summer and 12 days in winter. Daily ration was high from May to August (peaking in June) and very low in winter. Both sexes of pike exhibited a spawning fast in late April. Female rations were 1.5 to 2.3 times the male values in summer and winter. The rare inclusion of large prey items, such as suckers and burbot, had a very significant effect on the total caloric intake of pike.