Effects of fishing and environmental parameters on the commercial bony fish assemblage in the southern Caspian Sea

Since the 1990s, anthropogenic activities have been major direct or indirect threats to structural and functional organization of unique ecosystem Caspian Sea (CS). This study attempts investigate relationships between fish community structure environmental parameters analyze Abundance Biomass Comparison (ABC) in CS. The input data, including catch data by species parameters, were collected from 1996 2017. Of 13 bony identified, only two Rutilus kutum Chelon aurata accounted for 47.14% 62.65%, 40.80% 29.34% CPUE NPUE, respectively. DisTLM revealed that five variables showed a significant linear relationship with NPUE resemblance matrix. Based on AIC criteria, combination year, precipitation, SST_Apr, SSL, SST, GTA, Iranian rivers, Volga discharges explain 80.3% total variability. ABC curves W statistics, it was concluded assemblage environmentally stressed 2003. Shannon diversity index (H´) decreasing trend, suggesting exposed increasing stress over past 22 years. Considering current conditions (downward trend SSL river discharge increase SST) activities, appears downward will continue future.