Diet changes in Scotian Shelf haddock during the pelagic and demersal phases of the first year of life

Abstract

The diet of haddock Melanograrnmus aeglefinus from the southern Scotian Shelf was studied during their first year of Me. WMe haddock were pelagic, copepods were the numerically dominant component in the diet, with a significant benthic contribution (amphipods, polychaetes) first occurring in late summer. Examination of gut contents indicated that the transition from pelagic to demersal Life occurred relatively suddenly. Catch rates did not vary with die1 periodicity and gut contents of demersal fish had few occurrences of pelagic prey, indicating that diel migration was likely not an important aspect of the ecology of age 0 fish. Dietary changes during the months subsequent to the pelagic-demersal transition were minor relative to those associated with the transition itself, although some trends in importance of dietary items were observed, notably with copepods and mysids. Such trends did not appear to be related to the size of age 0 haddock.