POPULATION GENETIC-STRUCTURE OF EUROPEAN HAKE, MERLUCCIUS-MERLUCCIUS

Allozyme analysis of tissue samples of 910 European hake Merluccius me rluccius from six North Atlantic Ocean and four Mediterranean Sea loca tions revealed polymorphism at 21 out of 34 protein-coding loci examin ed. A major subdivision between Atlantic and Mediterranean collections (mean Nei's genetic distance within regions 0.005; between regions 0. 014) was particularly evident from allelic differences at the GAPDH-1 and GR-2 loci. Further population subdivision was indicated within b oth regions, and gene flow from adjacent Atlantic to proximal Mediterr anean populations was suggested by allele frequencies and relevant oce anographic and geological information. The data support present manage ment based on distinct Atlantic and Mediterranean populations and indi cate that the population structure within the Atlantic is more complex than the discrete northern and southern stocks proposed by ICES.