College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Juneau, Alaska, USA.
Alaska Center for Conservation Science, University of Alaska Anchorage, Anchorage, Alaska, USA.
Glob Chang Biol. 2024 Oct;30(10):e17508. doi: 10.1111/gcb.17508.
Disentangling the influences of climate change from other stressors affecting the population dynamics of aquatic species is particularly pressing for northern latitude ecosystems, where climate-driven warming is occurring faster than the global average. Chinook salmon (Oncorhynchus tshawytscha) in the Yukon-Kuskokwim (YK) region occupy the northern extent of their species' range and are experiencing prolonged declines in abundance resulting in fisheries closures and impacts to the well-being of Indigenous people and local communities. These declines have been associated with physical (e.g., temperature, streamflow) and biological (e.g., body size, competition) conditions, but uncertainty remains about the relative influence of these drivers on productivity across populations and how salmon-environment relationships vary across watersheds. To fill these knowledge gaps, we estimated the effects of marine and freshwater environmental indicators, body size, and indices of competition, on the productivity (adult returns-per-spawner) of 26 Chinook salmon populations in the YK region using a Bayesian hierarchical stock-recruitment model. Across most populations, productivity declined with smaller spawner body size and sea surface temperatures that were colder in the winter and warmer in the summer during the first year at sea. Decreased productivity was also associated with above average fall maximum daily streamflow, increased sea ice cover prior to juvenile outmigration, and abundance of marine competitors, but the strength of these effects varied among populations. Maximum daily stream temperature during spawning migration had a nonlinear relationship with productivity, with reduced productivity in years when temperatures exceeded thresholds in main stem rivers. These results demonstrate for the first time that well-documented declines in body size of YK Chinook salmon were associated with declining population productivity, while taking climate into account.
“Disentangling the influences of climate change from other stressors affecting the population dynamics of aquatic species” 为动名词短语，可译为“解析气候变化对水生物种种群动态的影响与其他压力因素的区别”。
“range”在这里不是“范围”的意思，而是“分布区”，可译为“分布区”。
“resulting in fisheries closures and impacts to the well-being of Indigenous people and local communities” 为现在分词短语作结果状语，可译为“导致渔业关闭以及对土著人民和当地社区福祉的影响”。
“indices of competition” 为名词短语，可译为“竞争指数”。
“adult returns-per-spawner” 为复合名词，可译为“每尾亲鱼的洄游成鱼数”。
“across most populations” 为介词短语作状语，可译为“在大多数种群中”。
“had a nonlinear relationship with productivity” 为固定搭配，可译为“与生产力呈非线性关系”。
“thresholds” 在这里不是“门槛”的意思，而是“（河川的）最低水位”，可译为“最低水位”。
解析完毕，译文如下：
解析气候变化对水生物种种群动态的影响与其他压力因素的区别，特别是在北纬地区的生态系统中，这些地区的气候驱动型变暖速度快于全球平均水平。育空-科尤库克地区（YK）的奇努克鲑鱼（Oncorhynchus tshawytscha）位于其物种分布区的最北端，其数量一直在持续减少，导致渔业关闭，并对土著人民和当地社区的福祉产生影响。这些减少与物理因素（如温度、水流）和生物因素（如体型、竞争）有关，但仍不确定这些驱动因素对各种群生产力的相对影响，以及鲑鱼与环境的关系在各流域之间的差异。为了填补这些知识空白，我们使用贝叶斯分层种群-补充模型，估计了海洋和淡水环境指标、体型和竞争指数对育空-科尤库克地区 26 个奇努克鲑鱼种群生产力（每尾亲鱼的洄游成鱼数）的影响。在大多数种群中，生产力随着亲鱼体型变小和冬季海水温度较低、夏季海水温度较高而下降。生产力下降还与秋季最大日流量高于平均水平、幼鱼外移前海冰覆盖增加以及海洋竞争者的丰度增加有关，但这些影响的强度在不同种群之间有所不同。在产卵洄游期间，每日最高水温与生产力呈非线性关系，当温度超过主要河流的最低水位时，生产力会降低。这些结果首次表明，育空-科尤库克地区奇努克鲑鱼体型的明显减小与种群生产力的下降有关，同时也考虑了气候变化的因素。
