Abstract
Zooplankton are a primary component of the aquatic food chain and play an important role in the functioning of aquatic food webs. Seasonal variation in community structures of zooplankton and potential environmental drivers were studied during a 1-year cycle (summer 2015 – spring 2016) in subtropical maritime channel systems in the Bay of Bengal, coastal waters in Bangladesh. A total of 32 species representing 25 families, 13 orders and 15 taxonomic groups were identified. Of these species, 23 were distributed in all four seasons, of which 8 were dominant species with high contributions to the total community. Species number peaked in autumn and fell in summer, while maximum abundance was in winter and minimum in summer. Multivariate analyses showed that there was a clear seasonal shift in zooplankton community structures in relation to environmental conditions. Species diversity and evenness peaked in summer, while the highest value of species richness was found in autumn. Multivariate correlation (RELATE) and BIO-ENV analysis demonstrated that seasonal variation in community patterns was significantly correlated with temporal shifts in environmental conditions and that variation was mainly driven by water transparency, salinity, DO, TSS, and nutrients. Thus, this finding implies that the zooplankton community represented a clear seasonal shift shaped by environmental drivers in subtropical channel systems.