Diversity of the fi sh species important for fi shery on the territory of Serbia has changed both spatially and temporally. Temporal changes are connected with historical and anthropogenic factors, while spatial changes are mostly the results of anthropogenic activity. Based on the analysis of the "BAES-ex situ" national database, there are two temporal and spatial periods. The fi rst period (from 1860 to 1950) is characterised by great diversity of the fi sh species important for fi shery in natural ecosystems, above all in rivers. The second period (from 1950 until today) is characterised by reduction in the diversity of the fi sh species important for fi shery, especially sturgeon species, in natural ecosystems, predominantly rivers, and the increasing diversity in anthropogenic water ecosystems. The increasing diversity in accumulations is predominantly related to Cyprinidae and Percidae species. The reduction in diversity in natural ecosystems is most often the result of irrational fi shery, habitat degradation, prominent anthropogenic infl uence and presence of introduced species. Many species important for fi shery are, according to the newest legal regulations of the Republic of Serbia, classifi ed in the category of strictly protected and protected species, and the permanent close hunting season or close season in certain periods and ban on hunting for individuals below prescribed size was declared for many of them. Taking into consideration prominent reduction in diversity, some of the fi sh species important for fi shery are also in "The preliminary list of species for the Serbian red list of vertebrates" because they are in danger of being extinct
