Soft bottom macrobenthos are highly diverse benthic invertebrates, and their diversity depends mainly on the health of the benthic habitat. The impact of anthopogenic stress and port related activites on macrobenthos diversity was studied in New Mangalore port, a tropical monsoon influenced environment. A shift in the macrobenthos abundance and diversity was observed with seasons, along with shift in the dominance of opportunistic species. The ecological quality status (EcoQS) indicated 'poor' to 'moderate' and also 'bad' status of benthic habitat, and this changed with the seasons and regions within the port. Higher diversity of macrobenthos at stations located in the high circulation area (HCA) compared to low circulation area (LCA) and oil and fertilizer wharf (OFW) indicated pivotal role of local hydrodynamics and activities within the port in structuring macrobenthos diversity. The occurrence of opportunistic species within the port demonstrated the role of anthropogenic stress in structuring macrobenthos community.
