Electrophoretic studies and the stock concept in marine teleosts

Abstract

Many of the commercially important marine teleosts appear to be subdivided into stocks or discrete spawning populations. A review of electrophoretic data on more than 20 marine teleosts reveals little genetic divergence between the recognized stocks separated by wide sea areas. The majority of genetic variation, detected by gelelectrophoresis, is present within and not between spawning groups. Demersal species show distinct electromorph frequencies, at some loci, between major sea areas but not a series of genetically isolated spawning groups. Pelagic species show little genetic differentiation over wide sea areas. The idea of discrete stocks appears to be based on a typological concept which on genetic grounds has no taxonomic status. Electrophoretic studies shift the emphasis away from routine stock identification to understanding genetic aspects of recruitment. Future management decisions on fish resources will need to take account of the high genetic variability within areas and the low genetic differentiation between areas.