Enzymatic polymorphism was used to detect variability within Notothenia rossii from two sites on the Kerguelen Plateau and Champsocephalus gunnari from the same sites and the South Orkney Islands. No polymorphism was found in the second species and it was low but not statistically significant in the first. This apparent homogeneity does not substantiate suggestions from other results that the populations can be separated, especially in the case of C. gunnari. Other approaches will be necessary to solve definitively the question of population separation.