Seasonal variation of the Malascostraca (Crustacea) fauna and their relationship with physicochemical parameters in Seyhan Basin, Türkiye.

This study aimed to investigate the seasonal distribution of the Malacostraca fauna in the Seyhan Basin by examining their relationship with some physicochemical parameters. Field studies were done in the spring, summer, and autumn of 2019 at 23 stations. As a result, 4302 individuals were examined, and 5 families (Niphargidae, Gammaridae, Palemonidae ve Potamidae) and 10 species belonging to the orders Amphipoda and Decapoda were recorded. Echinogammarus ischnus, Gammarus mladeni and G. pseudanatoliensis are the first records for this basin. According to the results of the Shannon-Wiener diversity (H) index, the highest diversity was calculated at station 11 in the spring (0.72), at station 22 (0.66) in the summer and autumn, the lowest diversity was recorded at station 3 in the spring (0.22) and autumn (0.05), and at station 1 in the summer (0.17). According to Shannon Evenness (E), the most balanced distribution was found at station 22 in the spring and summer (0.97), and at station 1 in the autumn (0.96). The stations with the lowest homogeneity were determined as at station 3 in the spring (0.22) and autumn (0.53), and at station 1 in the summer (0.59). According to the results of the clustering analysis, the highest similarity was observed between the 3rd and 5th stations (89%), while the 2nd station was determined to be the station with the lowest similarity, separating from all other stations. According to the Pearson correlation analysis, a significant negative correlation was observed between DO and temperature and total nitrogen, while a significant positive correlation was found between temperature and EC (P<0.01). When the water quality classes of the stations are examined according to the criteria of the Water Quality Regulation, stations have 1st (very clean) or 2nd (moderately polluted) class water quality. [ABSTRACT FROM AUTHOR]