Fish restocking as a conservation strategy: Challenges and opportunities

Defined as the controlled breeding and rearing of aquatic organisms, conservation aquaculture has emerged as a strategy to support the management and conservation of natural resources. This study provides a comprehensive review of the literature on the subject, covering articles published between 1990 and 2025. Conservation aquaculture can be classified into three categories. The first, enhance , involves the restocking of populations at risk of extinction and encompasses strategies such as restocking, stock enhancement, and sea ranching. The second, restore , focuses on the recovery of native habitats through the use of cultivated species with key roles in environmental stability. Finally, replace refers to supplementing market demand with cultured organisms, thereby compensating for the removal from wild stocks, reducing fishing pressure, and contributing to the long-term sustainability of natural populations. The findings suggest that conservation aquaculture cannot be regarded as a universal solution to population declines and should be applied cautiously, preferably as a last resort, due to its considerable economic demands and potential ecological risks. Among the strategies evaluated, replace emerges as the most promising approach for mitigating the impacts of extractive fisheries. The development of standardized metrics and operational guidelines is strongly recommended to guide future interventions and improve the effectiveness of aquatic biodiversity conservation. • Conservation outcomes of fish restocking programs are examined • Ecological roles of released species in enhancement initiatives are discussed • Case studies from marine and freshwater systems are reviewed • Ecological risks associated with species releases are highlighted • Monitoring and governance challenges in restocking programs are analyzed