FISH DIVERSITY ASSESSMENT OF THE IBAR RIVER: A 20-YEAR PERSPECTIVE

Abstract

The aim of this study was to present the diversity of the fish communities of the upper and lower reaches of the Ibar River in the last 20 years. We calculated several species diversity indices, namely the Shannon Index (H), Reciprocal Simpson’s Index (1/D), Fisher’s Alpha Diversity Index (A), Margalef’s Index, and Pielou’s Evenness Index (J). We recorded 16 fish species from 7 families between the 2003 and 2023 investigation period. The highest value of Shannon's diversity index was recorded in the upper course of the river (0.691), while the lowest was in the lower course (0.314) in 2017 and 2019. The relatively low values of diversity indices are most likely the consequence of the dominance of a few species, but they also may be the result of strong anthropogenic influence. Evenness Index ranged from 0.226 to 0.424, indicating a low level of homogeneity of fish assemblages. This study has contributed to the knowledge of fish diversity in the Ibar River and could assist in carrying out future ecological studies in line with conservation, restoration, and management strategies.