Genetic characterization of the northern shrimp, Pandalus borealis, in the Northwest Atlantic using electrophoresis of enzymes

Abstract

The genetic variability of the northern shrimp, Pandalus borealis, collected in the Saguenay Fjord, in six areas of the Estuary and the Gulf of St. Lawrence, and in two areas off the Labrador coast was assessed using eight enzymatic loci. Males, primiparous and multiparous females were sampled at all but one site in order to determine if gene frequencies within these regions of the Northwest Atlantic are temporally stable. For this protandrous species, variation of the genetic characteristics on a geographic scale and among maturity stages was largely determined by the variation occurring at the EST* HK- 1* and to a lesser extent at the HK-2* loci. The other loci did not vary significantly either on geographic or temporal scales. Deviations from Hardy-Weinberg expectations, all of them due to deficits in heterozygotes, were observed mainly at the same three loci and the number of deviations increased when males, primiparous and multiparous females were pooled. A cluster analysis of genetic distance did not reveal geographic patterns in the clustering of the samples. Although some rare private alleles were detected in the Gulf of St. Lawrence samples, the data suggest that gene flow is extensive across the study area.