Resource partitioning between Siberian sculpin (Cottus poecilopus Heckel) and Atlantic salmon parr (Salmo salar L.) in a sub-Arctic river, northern Norway |
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| Authors: | H -M Gabler P -A Amundsen |
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| Institution: | Institute of Marine and Freshwater Biology, Norwegian College of Fishery Science, University of Tromsø, Norway |
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| Abstract: | Abstract– Food resource partitioning between Siberian sculpin ( Cottus poecilopus ) and Atlantic salmon parr ( Salmo salar ) was investigated throughout a summer season in the subarctic River Reisa, northern Norway. The two species had almost identical diets, feeding primarily on benthic invertebrates and selecting the same prey species. There was no strong segregation in the diel feeding rhythms of the two species, although the salmon parr consumed a large proportion of their food at night during August and September. The results suggest that the two species compete for food, and that interspecific competition for limited food resources may explain the low production of Atlantic salmon in this river. The observation of a high degree of dietary overlap between the sculpin and the salmon parr contrasts with expectation of interactive segregation. Further, the findings conflict with general niche and competition theories, being inconsistent with the competitive exclusion principle. |
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| Keywords: | Atlantic salmon Siberian sculpin resource partitioning competition exclusive principle |
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