16 research outputs found
Stomach analyses of Baltic salmon from 1959-1962 and 1994-1997 : possible relations between diet and yolk-sac-fry mortality (M74)
Fast-flowing areas affect the feeding activity of migrating Altantic salmon smolts in tributaries of a subarctic river
Variation in the degree of silvering of wild coho salmon, Oncorhynchus kisutch, smolts migrating seaward from Carnation Creek, British Columbia
The physiological state of young Atlantic salmons Salmo salar (Salmonidae, Salmoniformes) from natural spawning and juveniles grown at a Fish Hatchery
Diel migration patterns of Atlantic salmon smolts with particular reference to the absence of crepuscular migration
Abstract – The real-time diel pattern of Atlantic salmon smolt migration was observed for 8 years using automatic resistivity counters verified by video surveillance. A clear dominant nocturnal migration was demonstrated early in the migration period, later becoming increasingly diurnal, until rates became approximately equal at day and night. Migration patterns were related to water temperature, such that when mean daily temperatures were below 12 °C, hourly rates of migration were significantly lower during the day than at night. When daily mean temperatures exceeded 12 °C, there was no significant difference between diurnal and nocturnal migration rates. Migration patterns showed a distinct suppression of migration at dawn and dusk throughout the migration period. It is hypothesised that this behaviour is an active decision and/or an adaptive strategy either to take advantage of increased food in the form of invertebrate drift or to reduce predation risk from actively feeding piscivores or both