The article outlines the closed fishing season for spawning fish species in the Paraná, Paraíba do Sul, and Ribeira de Iguape river basins in São Paulo State, Brazil, which runs from November 1, 2021, to February 28, 2022. This regulation, enforced by the Fisheries Institute (IP-APTA) and the Brazilian Institute for the Environment and Renewable Resources (IBAMA), aims to safeguard native aquatic life by imposing a ban on fishing certain species. It also requires fishermen, traders, and industries to declare their fish stocks to IBAMA before the season, to ensure compliance with the closed season regulations. Despite the ban on specific fish, the closed season permits fishing for non-native species, hybrids, and Malaysian giant shrimp under certain conditions. Additionally, fishing in reservoirs with specific equipment and restrictions is allowed for both amateur and professional fishermen.