Structural variability and composition of fish communities in the northern continental shelf of the Bay of Bengal, Bangladesh

The structural variability and composition of fish communities in the northern continental shelf of the Bay of Bengal, Bangladesh were assessed from monsoon 2014 to pre-monsoon 2015. A total of 73 species belonging to 43 orders, comprising 61 species of finfishes and 12 species of shellfishes were identified from estuarine set bag net (ESBN) fisheries. Of these, sixty species were commonly found throughout the study period and while nine species were dominant with higher contribution to the total communities. Community parameters and abundance were higher in monsoon and lower in winter. Multivariate analysis revealed a clear structural and compositional variation in fish communities. Furthermore, RELATE (coefficient of correlation between the fisheries communities and environmental parameters) and BIOENV/BEST (Biotaenvironment best matching) analyses showed that these variations were driven by both single (transparency) and multistressors [transparency in combination with associated factors such as salinity, total dissolved solids (TDS), total suspended solids (TSS), phosphate-phosphorus (PO4-P) and nitrite-nitrogen (NO2-N)]. Community parameters showed significant positive correlation with transparency, salinity and PO4-P which indicated that structure of fish communities is shaped by ecological conditions in this coastal habitat.