Racial Differences in Irish Sea and North Sea Plaice (Pleuronectes platessa)

Abstract

MERISTIC characters have played an important part in racial studies of fish¹, but little is known about their genetics. Schmidt's classical studies^2,3 on the genetics of vertebral numbers in natural populations of Zoarces viviparus and in hatchery-reared trout show that there is a considerable degree of genetic determination for these characters, and some evidence for genetic isolation in the highly localized populations of Zoarces viviparus of the fiords and open sea along the Norwegian coast. Similar studies have not been reported for marine fish of economic importance, although in some cases this seems to be a promising approach to the problems of racial separation.