Structural patterns of fisheries communities with relation to ecological condition in subtropical coastal waters of the northern Bay of Bengal, Bangladesh

Abstract

Fisheries assemblages with notes on the ecological conditions in coastal waters of the northern Bay of Bengal, Bangladesh, were investigated based on beach seine fishing net data form a one-year cycle (2015-2016) data collected by beach seine net. A total of 75 species comprising of 61 finfishes, 7 shrimps, 2 cephalopods, 2 lobsters and 3 crab species were identified. Among them, 58 species were commonly distributed in all four seasons, while 16 species were found dominant to the total communities. The species number, richness, evenness, and species diversity peaked in the monsoon and fell in the winter. Multivariate analysis of CAP and dbRDA revealed that there were clear temporal and spatial variations in fisheries assemblages in the Kohelia channel. RELATE analysis showed a significant correlation between fisheries communities with environmental variables. Furthermore, best matching analysis (BEST/BIOENV) confirmed that these temporal and spatial variations were driven by changing salinity, transparency and nutrients either alone or combined with soil nutrients. Thus, these findings suggest that fisheries community structure is shaped by the ecological condition in this marine channel system.