Canadian Journal of Fisheries and Aquatic Sciences, Volume 78, Issue 5, Page 623-630, May 2021.
Small pelagic fish support some of the largest fisheries globally, yet there is an ongoing debate about the magnitude of the impacts of environmental processes and fishing activities on target species. We use a nonparametric, nonlinear approach to quantify these effects on the Pacific sardine (Sardinops sagax) in the Gulf of California. We show that the effect of fishing pressure and environmental variability are comparable. Furthermore, when predicting total catches, the best models account for both drivers. By using empirical dynamic programming with average environmental conditions, we calculated optimal policies to ensure long-term sustainable fisheries. The first policy, the equilibrium maximum sustainable yield, suggests that the fishery could sustain an annual catch of ∼2.16 × 105 tonnes. The second policy with dynamic optimal effort, reveals that the effort from 2 to 4 years ago impacts the current maximum sustainable effort. Consecutive years of high effort require a reduction to let the stock recover. Our work highlights a new framework that embraces the complex processes that drive fisheries population dynamics yet produces simple and robust advice to ensure long-term sustainable fisheries.

中文翻译：

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环境变化和捕捞对加利福尼亚湾太平洋沙丁鱼渔业的影响

《加拿大渔业和水生科学杂志》，第78卷，第5期，第623-630页，2021年5月。
小型中上层鱼类为全球一些最大的渔业提供了支持，但有关环境过程和捕捞活动对目标物种的影响程度的争论仍在不断。我们使用非参数，非线性方法来量化对加利福尼亚湾的太平洋沙丁鱼（Sardinops sagax）的这些影响。我们表明，捕鱼压力和环境可变性的影响是可比的。此外，在预测总捕获量时，最好的模型会同时考虑这两个驱动因素。通过在平均环境条件下使用经验动态规划，我们计算出了确保长期可持续渔业的最佳政策。第一项政策，即平衡的最大可持续产量，表明该渔业的年捕捞量可以维持在2.16×105吨左右。动态尽力而为的第二个策略，揭示了2到4年前的努力影响了当前最大的可持续努力。连续多年的努力需要减少以使库存恢复。我们的工作着重强调了一个新框架，该框架涵盖了推动渔业种群动态的复杂过程，同时又提出了简单而有力的建议，以确保长期可持续的渔业。