Genetic Structuring Of Pandalus Borealis In The North Atlantic I. Allozyme Studies

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The population structure of the shrimp, Panda/us borea/is (Krnyer 1838), in the NE-Atlantic is presently being studied using two difJerent approaches, allozymic variation and RAPDs (randomly amplified polymorphic DNA; reported elsewhere). 28 different subsamples and close to 4000 specimens of shrimp have been analyzed for variation at three pol)morphic enzyme coding loci, AfilH, PGM and GP/. Most of the reported heterogeneity in allele frequencies was due to variation at.MDH. The shrimp were caught at various locations in open Barents Sea waters, in ·waters off Svalbard and Jan Mayen, and in fjords in western and northern Norway. Little genetic differentiation has been revealed among samples caught in the open Barents Sea, off Svalbard and off Jan Mayen. The shrimp caught in Tanafjorden and Varangerfjorden, the two easternmost fjords in northern Norway, are also genetically indistinguishable from Barents Sea shrimp. The shrimp caught in the other fjords in northern Norway (Troms), however, are distinct from the former group. There is a significant among-fjord variation in northern Norway. Moreover, fjord populations in northern Norway differ significantly in allele frequencies from shrimp caught in fjords in western Norway. The results are consistent with those found using RAPDs (CM 1997 /f:24) and support the previously proposed existence of only one population of P. borealis in the Barents Sea, which includes shrimp from Spitsbergen. Both the allozyme and RAPD assay showed clear differentiation between the Barents Sea group and Norwegian coastal samples of shrimp.