Salmon (Salmo salar) and sea-trout (Salmo trutta) restocking efficiency in potential rivers of Lithuania. Initial study

• Main Authors: Virbickas, Tomas, Kesminas, Vytautas
• Format: Article in Journal/Newspaper
• Language: Lithuanian; English
• Published: 2002
• Subjects: Atlantic salmon; Sea-trout; Restocking; Mortality; Migration; Salmo salar
• Online Access: http://lmavb.lvb.lt/LMAVB:ELABAPDB5148287&prefLang=en_US

The article presents initial data on salmon (Salmo salar) and sea-trout (Salmo trutta) restocking efficiency in potential rivers of Lithuania. 0+ juveniles were released into rivers in spring with the abundance of surviving individuals evaluated in autumn. Restocking efficiency was found to be considerably higher in those river stretches where fish migration towards the lower river reaches was restricted to weirs. About 30-50% of the juveniles released in spring survived in these localities until autumn. The relative abundance of juveniles in the stretches open to migration fluctuated in the wide range: salmon relative abundance varied from 0.1 to 16.1% (5.0% on average) and that of sea-trout - from 1.2 to 76.4% (24.4% on average). Salmon juveniles were found to display a much stronger tendency to migrate downstream from their release site than the juveniles of sea-trout. Still stronger liability to migrate towards the lower river reaches is characteristic of salmon juveniles that were raised until autumn and released into rivers. Salmon and sea-trout juveniles were noticed to select slightly different habitats.