Ichthyofauna composition and population parameters of fish species from the special nature reserve Koviljsko-Petrovaradinski Rit (Vojvodina, Serbia)

Abstract

Qualitative and quantitative ichthyofauna composition, morphometric characteristics, sex ratio, age and growth for fish species from Koviljsko-Petrovaradinski Rit were examined. A total of 1715 individuals which were classified into 18 species, from 7 families, were caught between August 2006 and October 2008. The greatest proportional contribution in total number of fish had Rutilus rutilus, while the greatest mass contribution had Carassius gibelio. Diversity and richness indices showed the highest values in the Dunavac locality. Female:male sex ratio varied from 1:0.33 in Sander lucioperca to 1:3.67 in Leuciscus idus and could not be observed in Aspius aspius, Neogobius fluviatilis and Cobitis taenia due to presence of only juvenile individuals. According to the scale readings, age distribution varied from I to VII year. The von Bertalanffy equation and growth performance index were determined by FiSAT II software in Esox lucius, Perca fluviatilis, Lepomis gibbosus, R. rutilus, L. idus, C. gibelio and Alburnus alburnus. Finally, distribution and population parameters of an invasive C. gibelio were discussed. Slightly poorer ichthyofauna diversity, low presence of economically significant species and reduced presence of individuals from higher age categories can point to irrational fishing, degradation of habitat, destruction of spawning areas and pronounced anthropogenic influence.