Diet of Silver Hake (Merluccius bilinearis) on the Scotian Shelf

Abstract

Predation or competition for similar food resources by silver hake (Merluccius bilinearis) has been reported to be associated with the decline in certain gadoid stocks off the northeastern USA. Speculation that the same mechanism may be active on the Scotian Shelf was investigated. The diet of silver hake found off New England and the Scotian Shelf were similar, however, the role of other gadoids such as haddock and cod in the diet of Scotian Shelf silver hake was not as important as that assumed for the New England area. Cannibalism was observed and believed to play a significant role in the regulation of this species. Silver hake on the Scotian Shelf were opportunistic predators preying heavily on crustaceans and fish. The diet was found to be predominantly invertebrates for ages 1-3, while after age 3 was largely fish. There appeared to be little differences in diet composition between males and females. Overall, the diet changed from one largely composed of fish in the spring and autumn to a mixed diet of fish, crustaceans and molluscs during the summer. There were differences in the diet composition at age during the three seasons studied, however, these changes seemed to reflect more the diet of younger versus older fish.

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

“…The southern stock consumes more crangonid shrimp, cancer crabs, decapod larvae, and cephalopods. Euphausiids, in particular Meganyctiphanes norvegica, are most abundant in the Gulf of Maine and on the Scotian Shelf, accounting for their high occurrence in hake diets in these regions (Waldron 1992). Both Illex sp.…”

“…This suite of morphological traits is consistent with the general trophic nature of hakes as ambush predators (Pitcher & Alheit 1995). The hakes are important invertebrate and fish predators in continental shelf systems worldwide, including the northeast Atlantic Ocean (Merluccius merluccius, Guichet 1995), the northeast Pacific Ocean (M. productus, Rexstad & Pikitch 1986, Tanasichuk et al 1991, the southeast Pacific Ocean off the Chilean coast (M. gayi, Arancibia 1987, Stobberup 1992, the southeast African coast (M. capensis, Pillar & Wilkinson 1995), and the northwest Atlantic (M. bilinearis, Bowman 1983, Waldron 1992, Helser et al 1995.…”

Guide to the Parasites of Fishes of Canada Part V: Nematoda

“…Key to species of Hysterothylacium from Canadian fresh-water fishes Description (after , 1992. With characteristics of the genus.…”

Scotian Shelf euphausiid and silver hake population changes during 1984–1996 measured by multi-frequency acoustics

“…1), is habitat for seasonally migrating stocks of silver hake (Merluccius bilinearis). Silver hake, which constitute the largest fish biomass on the Scotian Shelf (Waldron, 1988), feed principally on the euphausiid Meganyctiphanes norvegica (Koeller et al, 1989;Sameoto et al, 1994). M. norvegica, a diel migrator (Sameoto, 1980a;Cochrane et al, 1991Cochrane et al, , 1994, prefers the water depths exceeding 200 m provided by Emerald and other deep Scotian Shelf basins.…”