Population genetic structure of European hake, Merluccius merluccius

Abstract

Allozyme analysis of tissue samples of 910 European hake Merluccius merluccius from six North Atlantic Ocean and four Mediterranean Sea locations revealed polymorphism at 21 out of 34 protein-coding loci examined. 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 both regions, and gene flow from adjacent Atlantic to proximal Mediterranean populations was suggested by allele frequencies and relevant oceanographic and geological information. The data support present management based on distinct Atlantic and Mediterranean populations and indicate that the population structure within the Atlantic is more complex than the discrete northern and southern stocks proposed by ICES.