Diets of five hake species in the northeast United States continental shelf ecosystem

Abstract

We examined the diets of 5 hake species in the continental shelf ecosystem of the northeast USA: offshore hake Merluccius albidus, silver hake M. bilinearis, white hake Urophycis tenuis, red hake U. chuss, and spotted hake U. regia. We conducted a multivariate analysis of stomach contents from bottom-trawl surveys to assess the major factors that determine diet composition, to compare and contrast diets between species, and to compare the trophic role of the hakes in the northwest Atlantic to hakes in other ecosystems. These fish consume pelagic invertebrates (e.g. euphausiids and other shrimps) and pelagic fish prey, including conspecifics. The incidence of piscivory generally increases with increasing size. Regional and temporal (seasonal and yearly) variation in hake diets generally reflects differences in prey availability. Hakes are among the most abundant predators in continental shelf ecosystems worldwide. Fish prey consumption by hakes can be high and may be a primary source of mortality for economically important pelagic species. Hake predation plays an important role in the dynamics of both the US northeast continental shelf ecosystem and generally on a global scale.