Assemblage structure of bottom associated fishes in relation to environmental variables in the northeastern Persian Gulf, Iran

The assemblage structure of bottom associated fishes across the northern coast of the Persian Gulf has received little attention. The present study was conducted in the waters more than 10 m. of northeast coasts of the Persian Gulf. The autumn data of a bottom trawl survey targeting demersal fishes were used to describe the assemblage structures and their response to environmental variables. A total of 165 and 145 demersal fish species were sampled in 2014 and 2016, respectively. The assemblages were dominated by bony fishes, prevailed by Gilded goatfish (Upeneus doriae), followed by batoid fishes, prevailed by the Arabian banded whipray (Maculabatis randalli), and sharks, prevailed by Whitecheek shark (Carcharhinus dussumieri). The results indicated a reduction in the species richness over the two-year periods in the studied area. The highest species richness was observed at depths of 20 to 30 meters, with a downward trend to shallower and deeper waters. The BEST routine showed that temperature, EC, salinity and pH best described the distribution pattern of bottom-associated fishes in both years. Additionally, CCA analysis demonstrated three bathymetrical assemblage structures for bottom-associated fishes in the studied area. Among different environmental variables, the depth seems to be a major one distinguishing the communities.