Conservation of migratory fishes in the Amazon basin

1. The Amazon basin hosts the Earth's highest diversity of freshwater fish. Fish species have adapted to the basin's size and seasonal dynamics by displaying a broad range of migratory behaviour, but they are under increasing threats; however, no study to date has assessed threats and conservation of Amazonian migratory fishes.2. Here, the available knowledge on the diversity of migratory behaviour in Amazonian fishes is synthesized, including the geographical scales at which they occur, their drivers and timing, and life stage at which they are performed.3. Migratory fishes are integral components of Amazonian society. They contribute about 93% (range 77-99%) of the fisheries landings in the basin, amounting to -US$436 million annually.4. These valuable fish populations are mainly threatened by growing trends of overexploitation, deforestation, climate change, and hydroelectric dam development. Most Amazonian migratory fish have key ecological roles as apex predators, ecological engineers, or seed-dispersal species. Reducing their population sizes could induce cascading effects with implications for ecosystem stability and associated services.5. Conserving Amazonian migratory fishes requires a broad portfolio of research, management, and conservation actions, within an ecosystem-based management framework at the basin scale. This would require trans-frontier coordination and recognition of the crucial importance of freshwater ecosystems and their connectivity.6. Existing areas where fishing is allowed could be coupled with a chain of freshwater protected areas. Management of commercial and subsistence species also needs fisheries activities to be monitored in the Amazonian cities and in the floodplain communities to allow assessments of the status of target species, and the identification of management units or stocks. Ensuring that existing and future fisheries management rules are effective implies the voluntary participation of fishers, which can be achieved by increasing the effectiveness and coverage of adaptive community-based management schemes.

1. 亚马孙河流域拥有地球上最多样的淡水鱼类。鱼类物种通过表现出广泛的洄游行为来适应流域的规模和季节动态，但它们面临着日益增加的威胁；然而，到目前为止，还没有研究对亚马孙洄游鱼类的威胁和保护进行评估。 2. 在此，综合了有关亚马孙鱼类洄游行为多样性的现有知识，包括它们发生的地理范围、驱动因素和时间，以及进行洄游的生命阶段。 3. 洄游鱼类是亚马孙社会不可或缺的组成部分。它们约占该流域渔业捕捞量的93%（范围在77% - 99%之间），每年价值约4.36亿美元。 4. 这些珍贵的鱼类种群主要受到过度捕捞、森林砍伐、气候变化和水电大坝开发等日益增长的趋势的威胁。大多数亚马孙洄游鱼类作为顶级掠食者、生态工程师或种子传播物种具有关键的生态作用。其种群数量的减少可能会引发连锁反应，影响生态系统的稳定性和相关服务。 5. 保护亚马孙洄游鱼类需要在流域尺度的基于生态系统的管理框架内进行广泛的研究、管理和保护行动。这将需要跨境协调，并认识到淡水生态系统及其连通性的至关重要性。 6. 现有的允许捕鱼区域可以与一系列淡水保护区相结合。对商业和自给性物种的管理还需要对亚马孙城市和洪泛区社区的渔业活动进行监测，以便对目标物种的状况进行评估，并确定管理单位或种群。确保现有和未来的渔业管理规则有效意味着渔民的自愿参与，这可以通过提高基于社区的适应性管理方案的有效性和覆盖范围来实现。