The aim of the work was attempt of pricing of losses incurred by fishing plant, which runs production in the area of occurrence of species of water birds. Research was carried out by three methods: 1. calculating losses in potential ready production of fish, 2. calculating profitability of assets, which subject of research owns comparison to CPI factor of average profitability of fishing subjects, also of those which were socialized, 3. by comparative analyses of own results of research with data from literature. Scale of gotten production of fish in year of research amount to 156 kg*ha-1. Elimination of losses evoked by rapacious and fodder feed birds would allow boost of production of fish about 26 kg*ha-1 in year, but additional transition on intensive methods of production would boost production about 46 kg*ha-1. It would enable to increase value of production respectively about 198 PLN*ha-1 and about 331 PLN*ha-1.