Helminth parasites as biological tags in population studies of Greenland halibut (Reinhardtius hippoglossoides(Walbaum)), in the north-west Atlantic

Abstract

As part of a stock identification study, the parasite fauna of 608 Greenland halibut, Reinhardtius hippoglossoides (Walbaum) from six areas in the north-west Atlantic was examined. New records of parasite species for the Greenland area have been added by this study. No significant diVerences in prevalence were found between sexes or age groups of Greenland halibut. Three digeneans (Brachyphallus crenatus, Steganoderma formosum and Stenakron vetustum) and three nematodes (Anisakis simplex, Ascarophis sp., andContracaecumsp.) showed irregularities in spatial infestation pattern and were therefore chosen as biological tags. Nonparametric discriminant analyses of the prevalence of these parasites indicated strong similarities between components oV Labrador, Davis Strait, and in the fjords of Umanak at West Greenland. Greenland halibut in south-west Greenland fjords appeared to be isolated, as does the component in the Denmark Strait. This general pattern adds further support to previous investigations on stock structure of Greenland halibut in the North-west Atlantic. ? 1997 International Council for the Exploration of the Sea