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Research article2011Peer reviewed

High variability in spawning migration of sea trout, Salmo trutta, in two northern Swedish rivers

Östergren, Johan; Lundqvist, Hans; Nilsson, Jan

Abstract

P>Telemetry was used to examine spawning migration of sea trout, Salmo trutta L. (n = 126), in two rivers in northern Sweden. The spawning areas defined by radio-tagged fish differed between the river systems. In the River Vindelalven, sea trout spawned in the main stem and 80% of tagged individuals returned to areas where hatchery-reared juveniles had been previously stocked. In the River Pitealven, 74% of tagged sea trout ascended tributaries for spawning. Tagged fish were categorised into three groups of migratory pattern. cart (classification and regression tree) analysis indicated that distance from tagging location to spawning site (S(dist)) explained the migratory patterns. Large S(dist) separated fish with stepwise upstream migration from those with up- and downstream migrations and one-directional direct migration. Fish tagged early in the season migrated the longest distance to spawning areas. Stocking locations and sex explained the large search behaviour up- and downstream in the rivers. The findings are important for the sustainable management of sea trout in the Gulf of Bothnia.

Keywords

hatchery; homing; human impact; radio-tagging; salmonid; water temperature

Published in

Fisheries Management and Ecology
2011, Volume: 18, number: 1, pages: 72-82
Publisher: WILEY-BLACKWELL PUBLISHING, INC