Population genetic studies of northern shrimp, Pandalus borealis, in Icelandic waters and the Denmark Strait

The aim of this study was to describe the population structure of northern shrimp, Pandalus borealis, in Icelandic waters and the Denmark Strait, based on genetically determined and electrophoretically detectable protein variants. Muscle samples of 4417 specimens were collected from 24 sampling locations in three areas: inshore and offshore areas in Icelandic waters and Dohrnbank in the Denmark Strait. The samples were analysed by starch gel electrophoresis (Tris-citrate buffer, pH 7.0) and isoelectric focusing (pH ranging from 3.5 to 9.5 and from 4.0 to 6.5). Three enzymes displayed sufficient activity and allele variation to be used in the routine work: glucose phosphate isomerase, malate dehydrogenase, and phosphoglucomutase. The analyses revealed low mean heterozygosity and proportion of polymorphic loci, as is common for decapods in general. The results displayed significant genetic differences among shrimps inhabiting the three areas, especially between inshore shrimp on one hand, and shrimp from the offshore area and Denmark Strait on the other. For management purposes, the northern shrimp in the three areas should preferentially be treated as three biological units.