Non-native fish fauna in the lower Tigris Basin (Khuzestan Province, Iran)

The introduction of non-native species causes a variety of negative ecological and economic-social impacts on aquatic ecosystems. One of the first studies conducted on these species was the study of their composition and abundance in recipient ecosystems. The present study aimed to investigate the distribution, composition, and abundance of non-native fishes in the lower Tigris basin in a fishing year from fall 2014 to summer 2015. To update and compare the information, the latest fishing situation in the fishing year 2022-2023 was also examined. In total, 31 species from 15 families, including eight non-native species were caught from the studied water bodies. According to the results, non-native species are widely spread to the most aquatic ecosystems of the studied area, among which tilapia, including the redbelly tilapia Coptodon zillii (Gervais, 1848) and the blue tilapia Oreochromis aureus (Steindachner, 1864) were the most abundant species. The redbelly tilapia showed the most distribution in the studied area. According to the local fishermen, the amount of catch in many areas of inland waters of Khuzestan province has decreased compared to 2014-2015, and their statements indicate that they are not satisfied with the state of fishing.