Abstract

Ecosystem-based approaches are increasingly used in fisheries management to account for the direct trophic impacts of fish population harvesting. However, fisheries can also indirectly alter ecosystem structure and functioning, for instance via the provision of new feeding opportunities to marine predators. For instance, marine depredation, where predators feed on fishery catches on fishing gear, is a behaviour developed by many marine species globally. This behaviour can modify both the ecological role of predators and fisheries performance. Yet, these ecosystem-wide effects of depredation are rarely considered holistically. In this study, we explored different ways of incorporating depredation into an Ecopath trophic model. We assessed, through a subantarctic case study, how three alternative model structures can account for depredation effects on fishery catches, predator and non-commercial prey populations, as well as target fish stocks. While none adequately addresses all facets of depredation, the alternative models can to some extent capture how depredation can lead to increased fishing pressure on stocks. As structural specificities of Ecopath prevented us from representing other depredation effects such as provisioning effects for predator populations, we conclude this study with a set of guidance to effectively capture the complex effects of depredation in marine ecosystems and fisheries models.

中文翻译：

---

比较将捕捞捕捞纳入Ecopath的方法

摘要

在渔业管理中越来越多地采用基于生态系统的方法来说明鱼类种群收获的直接营养影响。但是，渔业也可以间接改变生态系统的结构和功能，例如通过向海洋捕食者提供新的觅食机会。例如，海洋掠食活动是捕食者以渔具捕捞渔获物为食的行为，是全球许多海洋物种开发的一种行为。这种行为既可以改变捕食者的生态作用，又可以改变渔业的表现。但是，这些折旧在整个生态系统中的影响很少被整体考虑。在这项研究中，我们探索了将折旧纳入Ecopath营养模型的不同方法。我们通过亚南极案例研究评估了 三个替代模型结构如何解释捕捞对捕捞量，捕食者和非商业猎物种群以及目标鱼类种群的影响。尽管没有一个方法能够充分解决折旧的所有方面，但替代模型可以在某种程度上反映出折旧如何导致种群捕捞压力增加。由于“生态路径”的结构特殊性使我们无法代表其他掠夺作用，例如对捕食者种群的供应作用，因此，本研究以一套指导作为结论来有效捕获海洋生态系统和渔业模型中掠夺的复杂影响。替代模型可以在一定程度上反映出掠夺行为如何导致种群增加捕鱼压力。由于“生态路径”的结构特殊性使我们无法代表其他掠夺作用，例如对捕食者种群的供应作用，因此，本研究以一套指导作为结论来有效捕获海洋生态系统和渔业模型中掠夺的复杂影响。替代模型可以在一定程度上反映出掠夺行为如何导致种群增加捕鱼压力。由于“生态路径”的结构特殊性使我们无法代表其他掠夺作用，例如对捕食者种群的供应作用，因此，本研究以一套指导作为结论来有效捕获海洋生态系统和渔业模型中掠夺的复杂影响。