School of Aquatic and Fishery Sciences, University of Washington, Seattle, Washington, USA.
Conservation Biology Division, Northwest Fisheries Science Center, National Oceanic and Atmospheric Administration, Seattle, Washington, USA.
Glob Chang Biol. 2022 Mar;28(6):2026-2040. doi: 10.1111/gcb.16049. Epub 2021 Dec 24.
Pacific salmon (Oncorhynchus spp.) are exposed to increased environmental change and multiple human stressors. To anticipate future impacts of global change and to improve sustainable resource management, it is critical to understand how wild salmon populations respond to stressors associated with human-caused changes such as climate warming and ocean acidification, as well as competition in the ocean, which is intensified by the large-scale production and release of hatchery reared salmon. Pink salmon (O. gorbuscha) are a keystone species in the North Pacific Ocean and support highly valuable commercial fisheries. We investigated the joint effects of changes in ocean conditions and salmon abundances on the productivity of wild pink salmon. Our analysis focused on Prince William Sound in Alaska, because the region accounts for ~50% of the global production of hatchery pink salmon with local hatcheries releasing 600-700 million pink salmon fry annually. Using 60 years of data on wild pink salmon abundances, hatchery releases, and ecological conditions in the ocean, we find evidence that hatchery pink salmon releases negatively affect wild pink salmon productivity, likely through competition between wild and hatchery juveniles in nearshore marine habitats. We find no evidence for effects of ocean acidification on pink salmon productivity. However, a change in the leading mode of North Pacific climate in 1988-1989 weakened the temperature-productivity relationship and altered the strength of intraspecific density dependence. Therefore, our results suggest non-stationary (i.e., time varying) and interactive effects of ocean climate and competition on pink salmon productivity. Our findings further highlight the need for salmon management to consider potential adverse effects of large-scale hatchery production within the context of ocean change.
太平洋三文鱼（Oncorhynchus spp.）面临着日益增加的环境变化和多种人为压力。为了预测未来全球变化的影响，改善可持续资源管理，了解野生三文鱼种群对与人类引起的变化相关的压力源的反应至关重要，这些变化包括气候变暖、海洋酸化以及海洋中的竞争，海洋中的竞争因大规模生产和释放养殖三文鱼而加剧。粉鲑（O. gorbuscha）是北太平洋的关键物种，支持着极具价值的商业渔业。我们研究了海洋条件变化和鲑鱼数量对野生粉鲑生产力的综合影响。我们的分析集中在阿拉斯加的威廉王子湾，因为该地区占全球养殖粉鲑产量的~50%，当地的养殖场每年释放 6 亿至 7 亿条粉鲑鱼苗。利用 60 年来有关野生粉鲑数量、养殖场释放和海洋生态条件的数据，我们有证据表明，养殖场释放的粉鲑会对野生粉鲑的生产力产生负面影响，可能是因为近海海洋生境中野生和养殖幼鱼之间的竞争。我们没有发现海洋酸化对粉鲑生产力的影响。然而，1988-1989 年北太平洋气候主导模式的变化削弱了温度与生产力之间的关系，并改变了种内密度依赖性的强度。因此，我们的研究结果表明，海洋气候和竞争对粉鲑生产力的影响是非平稳的（即随时间变化的）和相互作用的。我们的研究结果进一步强调了在海洋变化的背景下，鲑鱼管理需要考虑大规模养殖场生产的潜在不利影响。
