Biochemical Genetic Analysis of Population Differentiation in Greenland Halibut (Reinhardtius hippoglossoides) from the Northwest Atlantic, Gulf of St. Lawrence, and Bering Sea

Greenland halibut (Reinhardtius hippoglossoides) from the Northwest Atlantic Ocean, the Gulf of St. Lawrence, and the Bering Sea were analyzed for allele and genotype frequencies at 16 electrophoretically detectable protein loci. Thirteen of these loci were monomorphic, with identical mobilities in all samples. One locus (MDH-1) was polymorphic only in the Bering Sea sample. Two loci, PGM and PHI-2, were polymorphic in all samples. An analysis of allele frequencies at these latter loci indicated that Greenland halibut from the Northwest Atlantic area form a single genetically homogeneous stock, but that those in the Gulf of St. Lawrence form a separate though not completely isolated stock. Greenland halibut from the Bering Sea differ greatly from these, and a genetic distance estimate based on all 16 loci suggested genetic divergence at the subspecific level between the two oceans.