The behaviour, survival and production of Atlantic salmon ( Salmo salar L.) smolts in the Western Brook system (Salmo salar)

During spring/summer over a three-year period in the Western Brook system, Newfoundland, studies were conducted to gain general knowledge of the biology, ecology, and behaviour of juvenile anadromous Atlantic salmon for future use in management and research of this species in the system. More specifically, several sampling techniques, including mark-recapture experiments, were used to study fish size, age structure, population size, timing of migration, and migratory behaviour of juveniles in the system. Special attention was given to the effects of the fjord lake (Western Brook Pond) on migration and growth. The potential impacts of marking juveniles for recapture was also studied in the hatchery and in the field and found to be small. Atlantic salmon smolt production for the Western Brook system was estimated at 7 500–11 000 smolts per year, with the majority of emigrants being aged 3 years. Delayed migration in the lake was accompanied by increased growth and a lack of schooling behaviour. The contribution by the lake to the overall rearing and production of juveniles in the system is large (30–50%).