The delimitation of fishery stocks is an important aspect for the development and implementation of fishery stock management and sustainable use programs. Genetic analyses can provide useful information for the definition of population units, migration rates and changes in effective population sizes over long time frames. The black drum Pogonias courbina (Lacepede, 1803) is a marine fish that inhabits estuaries, bays and coastal waters of both hemispheres of the Western Atlantic, including Brazil, Uruguay and Northern Argentina. Intensely exploited at the Lagoa dos Patos Estuary in South Brazil, it is considered locally collapsed and since 2014 it is included in the National List of Endangered Fauna. Here we studied the population genetics of Pogonias courbina from South Brazil and the Argentinean and Uruguayan margins of the Río de la Plata Estuary, using the mitochondrial DNA control region. We showed that along the study area Pogonias courbina groups present high genetic diversity, no genetic structure, and are undergoing slight expansion. These characteristics favor resilience of the population, decreasing the extinction risk of local stocks. However, the slow recovery after the black drum fisheries collapse at Lagoa dos Patos indicates that the recolonization process is slow; this is corroborated by migration estimates, in which we observe a low number of migrants between Argentina/Uruguay and South Brazil. Therefore, we suggest that the South Brazil reproductive stock, impacted by regional fisheries, can be considered a unique stock in terms of management, independent of Uruguayan and Argentinean management strategies. However, an integrated management plan should ideally be considered for these groups, since impacts and conservation efforts are likely shared between areas.

中文翻译：

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大西洋西南部黑鼓（Pogonias courbina）种群的遗传连通性

渔业种群的划界是制定和实施渔业种群管理和可持续利用计划的一个重要方面。遗传分析可以为人口单位的定义、迁移率和长期有效人口规模的变化提供有用的信息。黑鼓 Pogonias courbina (Lacepede, 1803) 是一种海洋鱼类，栖息在西大西洋两个半球的河口、海湾和沿海水域，包括巴西、乌拉圭和阿根廷北部。它在巴西南部的 Lagoa dos Patos 河口被大量开发，被认为是局部坍塌，自 2014 年以来，它被列入国家濒危动物名录。在这里，我们使用线粒体 DNA 控制区域研究了来自巴西南部以及拉普拉塔河口的阿根廷和乌拉圭边缘的 Pogonias coubina 的种群遗传学。我们发现沿研究区的Pogonias coubina群体呈现出高遗传多样性，没有遗传结构，并且正在经历轻微的扩张。这些特征有利于种群的恢复能力，降低当地种群的灭绝风险。然而，Lagoa dos Patos 黑鼓渔业崩溃后的缓慢恢复表明重新殖民化进程缓慢；移民估计证实了这一点，其中我们观察到阿根廷/乌拉圭和巴西南部之间的移民数量很少。因此，我们建议受区域渔业影响的巴西南部繁殖种群，在管理方面可以被认为是一种独特的股票，独立于乌拉圭和阿根廷的管理策略。然而，理想情况下，应为这些群体考虑综合管理计划，因为影响和保护工作可能会在不同地区共享。