Seasonal variation of mesozooplankton communities in relation to environmental variables from a subtropical estuary of Bangladesh

Mesozooplankton are essential trophic intermediaries and bioindicators in estuarine ecosystems. However, their seasonal response to environmental variability remains underexplored in the subtropical estuaries of Bangladesh. This study investigated the seasonal variation of mesozooplankton community composition and its environmental drivers in the Moheshkhali Channel, southeastern Bangladesh, based on data collected between 2023 and 2024. Mesozooplankton were sampled using conical net tows, and environmental variables were measured concurrently. Community structure was analysed using ecological indices and multivariate approaches. A total of 24 taxa across six phyla were recorded, with copepods as the dominant group. Mesozooplankton abundance peaked in winter (1845 ind/m³), while diversity ( H′ = 0.90), evenness ( J′ = 0.33), and richness ( D mg = 2.33) were highest during…