THE GENETIC STOCK STRUCTURE OF THE AMERICAN LOBSTER (HOMARUS AMERICANUS) IN LONG ISLAND SOUND AND THE HUDSON CANYON

Abstract

The genetic population structure of the American lobster (Homarus americanus) was examined in populations collected in Long Island Sound (LIS) and the Hudson Canyon of the Northeastern United States with recently developed microsatellite DNA loci probes. Pereiopods, a thoracic appendage used for movement, feeding and defense, were collected from egg-bearing female lobsters from three sites within LIS—an eastern, central and western site—and from sites within the Hudson Canyon. Genomic DNA was isolated from each pereiopod and examined for nine microsatellite loci. Microsatellite allele frequencies, corrected for the presence of null alleles, were used to determine genetic differences between sampled groups. In agreement with earlier studies that used mitochondrial DNA and allozyme markers, there was little genetic differentiation between eastern and central LIS sites and the Hudson Canyon site. However, the genetic differences between western LIS populations and other sampled populations were 10 times higher. These were greater differences than could be attributed to geographical separation. These differences may have arisen as a result of the massive lobster die-off that occurred in 1998/1999 in western LIS.