Size Selective Predation Among Juvenile Salmonid Fishes in a British Columbia Inlet
Field observations suggest early sea mortality of pink (Oncorhynchus gorbuscha) and chum (O. keta) salmon fry is largely due to predation by juvenile coho (O. kisutch) salmon. A series of experiments demonstrates a strong bias toward the smaller individuals of the prey population. This results in an...
| Published in: | Journal of the Fisheries Research Board of Canada |
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| Main Author: | |
| Format: | Article in Journal/Newspaper |
| Language: | English |
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Canadian Science Publishing
1971
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| Subjects: | |
| Online Access: | http://dx.doi.org/10.1139/f71-231 http://www.nrcresearchpress.com/doi/pdf/10.1139/f71-231 |
| Summary: | Field observations suggest early sea mortality of pink (Oncorhynchus gorbuscha) and chum (O. keta) salmon fry is largely due to predation by juvenile coho (O. kisutch) salmon. A series of experiments demonstrates a strong bias toward the smaller individuals of the prey population. This results in an apparent growth rate 0.3–0.5% per day due to the biased mortality alone. With a high innate growth rate [Formula: see text], the prey are shown to "outgrow" the predator [Formula: see text], and hence become unavailable. Chums are shown to have an advantage over pinks through slightly earlier entry into the estuary and a larger initial size. The mechanism of selection used by the predator is not known from this study. |
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