The addition of natural reproduction of hydrobionts by the fish farming to provide a fishery resources and preserve the biological diversity of water ecosystems. Fish farming based on scientific recommendations in Russia according to federal legislation. The need to develop scientific recommendations has been related to the fact conditions of each water body determine the number of fish juveniles that can be provided with conditions for their growth. Currently, the term "maximum permissible volumes of release" (PDOV) used in regulatory documents governing the development of recommendations for fish farming. At the same time, the definition of this term is not given in the legislation, which implies its interpretation. The lack of explicit wording of the term makes it possible to use a variety of approaches and methods in the preparation of recommendations. Аs expected, the use of different methods gives different results. There is debate about the eligibility of applying different approaches when discussing the results, since each expert has a different view on the problem of determining the maximum permissible number for release. This situation indicates the need to approve unified methodological approaches to assessing the maximum permissible number of fish juveniles to release. It is necessary to supplement governing document with provisions in which, based on the availability and quality of available information on the reproduction conditions and the feed base of juvenile fish, existing methodological approaches to determining the maximum permissible number for release, various levels of information support can be distinguished to substantiate the maximum permissible number of fish juveniles.