Diel feeding rhythms and daily food consumption of juvenile Atlantic salmon in the River Alta, northern Norway |
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Authors: | P-A Amundsen ¶ R Bergersen † H Huru ‡ T G Heggberget § |
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Institution: | The Norwegian College of Fishery Science, University of Tromsø, N-9037 Tromsø;Malmvn. 208, N-9022 Krokelvdalen;Environmental Department, County Governor of Tromsø, N-9005 Tromsø;Norwegian Institute for Nature Research, Tungasletta 2, N-7005 Trondheim, Norway |
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Abstract: | 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. |
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Keywords: | feeding periodicity food consumption nocturnal feeding Atlantic salmon Salmo salar |
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