Chromosome Polymorphism Patterns Indicate Failure of a Scottish Stock of Salmo salar Transplanted into a Spanish River

Abstract

A river in the Asturias region of northern Spain was repopulated with fry originating from two different stocks of Salmo salar: native adults and a Scottish stock. A sample of parr captured in the river in 1989 showed the same pattern of chromosome polymorphism as the autochthonous stock released 6 mo before. We conclude that repopulation with the foreign stock was unsuccessful and that chromosome polymorphism patterns yield a useful method of stock discrimination in certain situations.