Does the introduced brook trout (Salvelinus fontinalis) affect growth of the native brown trout (Salmo trutta)?
- Kai KorsuAffiliated withDepartment of Biology, University of OuluFinnish Game and Fisheries Research Institute, Kainuu Fisheries Research Email author
- , Ari HuuskoAffiliated withFinnish Game and Fisheries Research Institute, Kainuu Fisheries Research
- , Timo MuotkaAffiliated withDepartment of Biology, University of OuluFinnish Environment Institute, Research Program for Biodiversity, University of Oulu
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Non-native brook trout have become widely established in North European streams. We combined evidence from an artificial-stream experiment and drainage-scale field surveys to examine whether brook trout suppressed the growth of the native brown trout (age 0 to age 2). Our experimental results demonstrated that brown trout were unaffected by the presence of brook trout but that brook trout showed reduced growth in the presence of brown trout. However, the growth reduction only appeared in the experimental setting, indicating that the reduced spatial constraint of the experimental system may have forced the fish to unnaturally intense interactions. Indeed, in the field, no effect of either species on the growth of the putative competitor was detected. These results caution against uncritical acceptance of findings from small-scale experiments because they rarely scale up to more complex field situations. This and earlier work suggest that the establishment of brook trout in North European streams has taken place mainly because of the availability of unoccupied (or underutilized) niche space, rather than as a result of species trait combinations or interspecific competition per se.
KeywordsAlien species Boreal streams Interspecific competition Multiscale Salmonids
- Does the introduced brook trout (Salvelinus fontinalis) affect growth of the native brown trout (Salmo trutta)?
Volume 96, Issue 3 , pp 347-353
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- Alien species
- Boreal streams
- Interspecific competition
- Industry Sectors
- Author Affiliations
- 1. Department of Biology, University of Oulu, P.O. Box 3000, 90014, Oulu, Finland
- 2. Finnish Game and Fisheries Research Institute, Kainuu Fisheries Research, Manamasalontie 90, 88300, Paltamo, Finland
- 3. Finnish Environment Institute, Research Program for Biodiversity, University of Oulu, P.O. Box 413, 90014, Oulu, Finland