• Salmo trutta;
  • brown trout: migratory behaiour;
  • gentics;
  • environment


Lake Storvindeln in northern Sweden supports a population of fast-growing lake-run brown trout. Spawning and early rearing take place in the River Vindelälven, while most growth occurs in the lake (piscivory). A smaller tributary to the lake, Låktabäcken Creek, holds a resident, early maturing, short-lived brown trout population, although no migratory barriers have existed since 1947. To establish a lake-run trout population, fry from the migratory R. Vindelälven stock were introduced into the creek during 1985–1991. Introduced trout descended to the lake prior to maturing. As a result of the introduction, large adult trout returned from L. Storvindeln to the creek to spawn in 1991 and 1992; i. e., the introduced trout were able to complete a migratory life cycle. Genetic factors appeared to have a primary influence on the predisposition to migrate in this case, and it is suggested that migratory populations rarely develop from strictly resident ones.