Increase in maturation size after the closure of a high seas gillnet fishery on hatchery‐reared chum salmon Oncorhynchus keta
Abstract Gillnet fisheries are strongly size‐selective and seem to produce changes in size at maturity for exploited fishes. After Word War II, large‐scale gillnet fisheries targeted Pacific salmon ( Oncorhynchus spp.) in the high seas area of the North Pacific and the Bering Sea, but these fisherie...
| Published in: | Evolutionary Applications |
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| Main Authors: | , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Wiley
2008
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| Subjects: | |
| Online Access: | http://dx.doi.org/10.1111/j.1752-4571.2008.00029.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1752-4571.2008.00029.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1752-4571.2008.00029.x |
| Summary: | Abstract Gillnet fisheries are strongly size‐selective and seem to produce changes in size at maturity for exploited fishes. After Word War II, large‐scale gillnet fisheries targeted Pacific salmon ( Oncorhynchus spp.) in the high seas area of the North Pacific and the Bering Sea, but these fisheries were closed in 1993. To assess the effects of this high seas gillnet fishery (and its closing) on size at maturity, we examined long‐term trends in size at 50% probability of maturing ( L 50) for chum salmon ( O . keta ) from three populations in Hokkaido, Japan. The L 50 trends were statistically different among rivers, but showed similar temporal patterns with decreases in the 1970s and early 1980s and increases after the 1985 brood year. While fishery‐induced evolution seemed largely responsible for this temporal change in L 50 during the fishing period, natural selection and phenotypic plasticity induced by environmental changes could contribute to the increases in L 50 after the relaxation of fishing pressure. |
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