SummaryWhite muscle samples of Antarctic fish (Notothenia rossii, N., neglecta. N. gibbe‐rifronsandChaenocephalus (aceratus) were subjected to electrophoretic tests. lsoelectric focusing of general muscle proteins provides a quick method of iden‐tyfying species. Six muscle enzymes were resolved by horizontal starch gel clectrophoresis. These are presumed to be the products of ten independent gene loci. Coefficients of genetic distance were calculated and substantially agree with the conventional taxnomy. Levels of genetic variability are within the normal range for marine teleosts. Two polymorphic enzymes. GPI and PGM. might prove useful as ‘genetic tags’ for stock identif