Parasites as indicators of populations and species of rockfishes: (Sebastes: Scorpaenidae) of the northeastern Pacific Ocean

Abstract

Parasitological data were used to investigate relationships of various species of rockfishes (Sebastes Cuvier, 1829) in the northeastern Pacific Ocean. Hesults indicated that different stocks of Sebastes alutus (Gilbert, 1890) are present along the continental shelf off the southwestern coast of Vancouver Island, British Columbia; in Queen Charlotte Sound and in the Gulf of Alaska, which can be differentiated through the intensities of infection of certain metazoan parasite species. Differences in the parasite fauna of S. alutus were also correlated with depth of capture and size of the host. Season of capture and sex of the host did not appear to influence the parasite faunas of S. alutus. Eight of the sixteen species of rockfishes obtained from Queen Charlotte Sound appeared to harbour parasites which could be used to differentiate host species. Large differences between the parasites of inshore and offshore rockfishes were observed. Species of inshore rockfishes could also be differentiated through the intensities of infection of their parasites. None of the parasites recovered exhibited strict host specificity; however, specificity to the genus Sebastes appeared to be rather well developed for most copepods and monogeneans. It is postulated that speciation may be occurring in some species of copepods and monogeneans as well as in the genus Sebastes.