Spatial and temporal variability in the diet of anadromous Arctic charr, Salvelinus alpinus, in northern Labrador

Abstract

Spatial and temporal variation in the diet of anadromous Arctic charr, Salvelinus alpinus, was determined from over 2500 prey-containing stomachs collected from three stock complex areas in northern Labrador. Based on the percent wet mass, sand lance, Ammodytes spp., capelin, Mallotus villosus, and sculpins, Triglops spp. and Myoxocephalus spp., were the most important components of the diet in the Voisey stock complex, with capelin, sand lance, and hyperiid amphipods, Parathemisto spp., dominating in the Nain region. In contrast, hyperiid amphipods and sculpins were the main prey items in the more northern Hebron—Saglek complex indicating that diet differs among stocks, and at times over limited spatial scales. The relative importance of prey varied with size of predator. Mean weight of charr has declined over time (p < 0.01), and for one stock complex, is highly correlated with the average quantity of capelin found in the stomachs (r2 = 0.66, p < 0.001). Dietary shifts observed in anadromous charr in some areas of northern Labrador could be associated, in part, with changes in the distribution of capelin in the northwest Atlantic Ocean, possibly as a result of anomalous ocean climate conditions.