A population genetic study of haddock (Melanogrammus aeglefinus) in Northeast Atlantic wafers based on isozyme data

The genetic population structure of haddock in Northeast Atlantic waters wa s studied using polymorphic isozyme loci as genetic markers. 3459 specimens from 38 locations were submitted to electrophoresis and genotyped at eight polymorphic isozyme loci. Allele frequency analysis gave no clear indicati ons of a genetic subdivision in the species within the Northeast Atlantic, but some geographic trends were seen: Haddock from Icelandic waters differe d somewhat at one locus. The allele frequency differences between the Icela ndic sample and the other samples were however small, and large samples, wh ich provide increased statistical power, seem to be necessary in order to e nable population discrimination. A tendency of genetic "isolation by distan ce" was observed in haddock collected in Norwegian fjord and coastal waters . No evidence of genetically distinct haddock stocks was found in any of th e represented Norwegian fjords. The genetically most deviating sample in th e study was collected in the Barents Sea. However, small sample size and he nce uncertainty in the allele frequency estimates prohibited firm conclusio ns on a distinct haddock population in the north.