Population genetic studies of the roughhead grenadier, Macrourus berglax L., in the North Atlantic Ocean

Samples of the roughhead grenadier, Macrourus berglax L., were collected fr om several locations off East and West Greenland and in the Norwegian Sea. A total of 651 individuals were screened using starch-gel electrophoresis t o reveal polymorphic systems to be applied in studies of the genetic struct ure of the species. Ten enzymes were stained for and seven enzyme loci (G3P DH-1*. GPI-1*, GPI-2*. LDH-1*, LDH-2*, MDH* and PGM*) displayed sufficient activity and allele variation to be used in the routine work. The GPI-1* an d PGM* loci displayed high heterozygosities. Tests of accordance between ob served distributions of phenotypes and expected Hardy-Weinberg distribution s as well as tests of heterogeneity among sampling Rites, were performed us ing chi (2) tests. No genetic differences within the three main areas (West Greenland, East Greenland and the Norwegian Sea) were revealed, while sign ificant differences were found among those areas indicating that the roughh ead grenadier in the North Atlantic is composed of different stock units wi th their own gene pools rather than belonging to one panmictic population. (C) 2001 Elsevier Science B.V. Ail rights reserved.