Helminth parasites of redfish (Sebastes fasciatus) from the Scotian Shelf, Bay of Fundy, and eastern Gulf of Maine

Abstract

Examination of alimentary tracts of 319 redfish (Sebastes fasciatus) from the Scotian Shelf, Bay of Fundy, and eastern Gulf of Maine yielded 13 helminth species: 7 Digenea, 3 Cestoda, 2 Nematoda, and 1 Acanthocephala. Total species composition was virtually identical with that found in the redfish of the Labrador–Newfoundland area. Prevalence and intensity of infection were low and showed little variation with area or fish length except in the case of the nematodes Anisakidae for which low prevalence and intensity (3.9 and 1.0, respectively) in the eastern Gulf of Maine contrasted with higher values (39.1–71.4 and 1.7–7.7, respectively) in the remainder of the survey area. The general pattern of species numbers was low numbers (2–4) in the fish of the Gulf of Maine and southwest Nova Scotia, and higher numbers (8–13) in those of the central and northeast Scotian Shelf. Small- to intermediate-sized fish contained more species (7–12) than the largest fish (4). The combination of exceptionally low prevalence of Anisakidae and low parasite species numbers in redfish of the eastern Gulf of Maine area suggests that the stock there is distinct from those of the Scotian Shelf and Bay of Fundy.