The rapid decline in Pacific cod (Gadus macrocephalus, Gadidae) biomass following multiple Gulf of Alaska marine heatwaves (2014–2016 and 2019) may be one of the most dramatic documented changes in a sustainably managed marine fishery. As such, fisheries managers are exploring new recruitment paradigms for Pacific cod under novel environmental conditions. In this review, we address the challenges of managing and forecasting Pacific cod populations in the Eastern Pacific where thermal habitats for early life stages are undergoing varying rates of change across space and time. We use observational data to examine changes in distribution, abundance and demographics of the population from 1993 to 2020, and model contemporary and future changes of thermal habitat for both spawning success and age-0 juvenile growth potential. Results indicate that reduced spawning habitat and early life stage abundance may be a precursor to regional population decline, but the recent apparent increases in size-at-age of pre-recruits will have unknown impacts on future recruitment in these regions. We contend that continued monitoring of early life stages will be necessary to track changes in phenology and growth that likely determine size-at-age and the survival trajectories of year classes into the adult population. These include complex size- and temperature-dependent energetics spanning seasonal habitats through the first winter. Climate-ready management of Pacific cod will, therefore, require new process investigations beyond single-season surveys focused on one-life stage.

中文翻译：

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人类世的太平洋鳕鱼：热栖息地变化下的早期生活史视角

阿拉斯加湾多次海洋热浪（2014-2016 年和 2019 年）后，太平洋鳕鱼（ Gadus macrocephalus ，Gadidae）生物量迅速下降，可能是可持续管理海洋渔业中最显着的记录变化之一。因此，渔业管理者正在探索新环境条件下太平洋鳕鱼的新招募模式。在这篇综述中，我们解决了管理和预测东太平洋太平洋鳕鱼种群的挑战，那里生命早期阶段的热栖息地正在经历不同的空间和时间变化率。我们使用观测数据来研究 1993 年至 2020 年种群分布、丰度和人口统计的变化，并为产卵成功和 0 岁幼鱼生长潜力模拟当代和未来热栖息地的变化。结果表明，产卵栖息地和生命早期阶段丰度的减少可能是区域种群数量下降的先兆，但最近新招募者的年龄体型明显增加将对这些地区未来的招募产生未知的影响。我们认为，有必要对早期生命阶段进行持续监测，以跟踪物候和生长的变化，这些变化可能决定年龄大小和年级到成年人口的生存轨迹。其中包括复杂的大小和温度依赖性能量，跨越第一个冬季的季节性栖息地。因此，太平洋鳕鱼的气候适应管理将需要在关注单一生命阶段的单季节调查之外进行新的过程调查。