Abstract:Mesozooplankton (Body size 20–200 μm) along with the surface water were collected from coastal regions of Sundarban, northeastern part of Bay of Bengal considering three seasons, namely premonsoon, monsoon and postmonsoon. Samples were analyzed for community structure and the dominant copepod species were further analyzed for trace metal concentration. In total, 50 copepods were identified (22 families and 43 genera). The dominant mesozooplankton species included 9 copepods and an epipelagic chaetognath, exhibited both spatial and seasonal variations. Metal concentration exhibited considerable inter-specific variations for the copepods and the mean concentrations were: Fe, 1350.2–51118.3 μg/g; Al, 647.2–73019.1 μg/g; Ni, 32.4–110.3 μg/g; Mn, 122.8–1066.5 μg/g; Pb, 0.04–97.5 μg/g; Pb, 10.6–97.5 μg/g; Cd, 4.2–21.6 μg/g; Cu, 17.4–145.1 μg/g; Zn, 225.7–1670.9 μg/g; Cr, 21.7–194.3 μg/g; Co, 1.32–111.1 μg/g. Metal concentrations showed the following order: Sagitta bedoti > Coryceas danae > Oithona sp. > Eucalanus subcrassus > Labidocera euchaeta > Paracalanus parvus > Acartiella tortaniformis > Acartia spinicauda > Pseudocalanus serricaudatus.