Biochemical Genetic Analysis of Population Differentiation in Greenland Halibut (Reinhardtius hippoglossoides) from the Northwest Atlantic, Gulf of St. Lawrence, and Bering Sea
Greenland halibut (R. 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 [SOD, AAT-1, AAT-2, LDH, GDPH, GDH, ICDH-1, ICDH-2, XDH, SDH, PHI-2, MDH and malic enzyme] 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 subsepcific level between the 2 oceans.