Hatchery fish stocking: case study, current Brazilian state, and suggestions for improvement

Hatchery fish stocking is one of the main actions adopted as a form of conservation and replacement of fishing stocks. Under Brazilian law, the release of fish has become mandatory and is seen as one of the main ways of mitigating the negative effects on fish populations and preserving the ichthyofauna. Since its institution, the efficiency of this method has been questioned by the Brazilian scientific community, due to the lack of monitoring based on scientific criteria. The objective of this work was to discuss the few available reports and to analyze their deficiencies and analyze the real risks and/or benefits arising from the methodologies employed in hatchery stocking activities developed in Brazil. For this, three different studies developed in the Paranapanema River, Southeast/South of Brazil, were evaluated seeking evidence of the efficiency or inefficiency of these actions, such as management of the conservation of fish species and stocks. Our analysis shows that this management policy is poorly evaluated, and review of the planning of the stocking programs is essential, in order to improve, update, modernize, and unify the knowledge of the producing stations with respect to the existing ecological and genetic studies, aiming at better monitoring and greater effectiveness in the results advance. Also, a protocol is suggested to standardize and guide new conservationist policies of hatchery fish stocking.