Threats and challenges for the conservation of marine molluscs in the southwestern Atlantic

The southwestern (SW) Atlantic is bordered by the coastlines of Brazil, Uruguay, and Argentina and is characterized by a great diversity of ecosystems, in which estuarine and marine molluscs are among the most representative invertebrates. The accelerating degradation of the environment due to human activity is resulting in the loss of species, leaving us insufficient time to comprehensively understand their morphology, ecological interactions, and the ecosystem services they provide. The aim of this manuscript is to review the conservation status of estuarine and marine molluscs in the SW Atlantic, identify the main threats and knowledge gaps, and indicate the challenges and prospects for their conservation. Physical degradation of environments, pollution, exotic species, and overexploitation of fishery resources are among the main non-climatic drivers threatening marine molluscs in the SW Atlantic. In addition, climate threats, such as rising temperatures and sea levels, and ocean acidification, create synergistic effects that are still not fully understood. Given this scenario, it is imperative to implement measures to mitigate this situation. These measures include strengthening management and governance to conserve habitats and control pollution and non-native species, with the aim of reducing ecosystem deterioration and establishing the foundations for monitoring environmental changes through long-term interdisciplinary projects. Additionally, there is a need to improve legislation aimed at regulating fishery practices. To achieve the effective conservation of estuarine and marine molluscs in the SW Atlantic, it is also essential to strengthen scientific dissemination projects and expand and support the training of researchers specialized in molluscs.