Diel feeding rhythms and daily food consumption of juvenile Atlantic salmon in the River Alta, northern Norway

• Published in: Journal of fish biology Vol. 54; no. 1; pp. 58 - 71
• Main Authors: Amundsen, P.-A., Bergersen, R., Huru, H., Heggberget, T. G.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.01.1999; Blackwell
• Subjects: Agnatha. Pisces; Animal and plant ecology; Animal, plant and microbial ecology; Animals; Atlantic salmon; Autoecology; Biological and medical sciences; feeding periodicity; food consumption; Fundamental and applied biological sciences. Psychology; nocturnal feeding; Salmo salar; Vertebrata; Norway; Europe; Freshwater environment; Salmonidae; Vertebrata; Food intake; Seasonal variation; Pisces; Salmo salar; Daily variation; Stream; Circadian rhythm; Young animal; Feeding
• ISSN: 0022-1112; 1095-8649
• DOI: 10.1111/j.1095-8649.1999.tb00612.x

Atlantic salmon fry (0+) sampled from the River Alta exhibited only minor differences in stomach content weights and feeding rates throughout diel periods, but feeding rates were generally lowest at night. In contrast, salmon parr (1+ to 3+) had large diel fluctuations in stomach content weight, with the largest weights usually being recorded during the night and early morning. Accordingly, their feeding rates were highest at night. This nocturnal feeding pattern was consistent throughout all sampling occasions, and appeared to reflect a persistent feeding periodicity in the salmon parr. The daily food consumption rates of both fry and parr were highest during midsummer and decreased towards autumn.