Temporal Variations in Phytoplankton Assemblages at Dol Net Fishing Grounds of Major Tidal Creeks of Maharashtra, India

Abstract

Phytoplankton dynamics plays a vital role in determining the productivity of any coastal ecosystem. In this study, temporal variability in phytoplankton composition and diversity was assessed with respect to the physico-chemical parameters of water in major dol net fishing grounds of two spatially adjacent tidal creeks (Thane and Vasai) of Maharashtra.The phytoplankters identified belonged to 84 and 69 species in Thane and Vasai creeks, respectively. Numerical abundance of phytoplankton ranged from 8.7×104 cells per litre to 4.3×105 cells per litre. Diatoms were the major group in both the creeks followed by dinoflagellates. Plankton density, diversity, evenness and richness were significantly higher in winter monsoon season. Phytoplankton density is positively correlated with phosphate, nitrate, nitrite, chlorophyll-a, diatoms and dinoflagellates, and negatively correlated with total suspended solids and silicates. Canonical correspondence analysis established that temperature, salinity and nutrients regulate the temporal patterns in phytoplankton composition. This study has provided fruitful insights on the diversity, abundance and temporal variations of phytoplankton assemblages under the influence of physico-chemical parameters of water in the tidal creeks of Maharashtra.