Nutrient and Plankton Abundance in the Major Nursery Grounds of Hilsa (Tenualosa ilisha) in Perspective of Water Quality Factors

Abstract

This study was contemplated to depict the nutrient composition and dissertation of plankton present in the six hilsa sanctuaries. The water temperature (25.6±0.8ºC), nitrate (0.005±0.01 mg/L), phosphate (0.002±0.0004 mg/L) and DO (7.7±1.1 mg/L) followed by pH (7.6±0.6), transparency (44.4±10.6 cm), alkalinity (112.4 ±26.4 mg/L), hardness (304.5±69.5 mg/L) and CO2 (10.3±1.2 mg/L). The chlorophyll a was estimated and represents the biomass of phytoplankton (8.21 ± 2.3 µg/L). Twelve groups (families) of phytoplankton (Bacillariophyceae, Ulvophyceae, Zygnematophyceae, Bacillariophyceae, Dinophyceae, Fragillariophyceae, Gonatozygeceze, Cyanophyceae, Hydrodictyaceae, Stephanodiscaceae, Trebouxiophyceae, Melosiraceae and Euglenoida) comprising 26 genera and zooplankton (Branchiopoda, Hexanauplia, Heterotrichea, Diaptomidae, Eurotatoria, Cryptophyceae, Rotifera, Copepod, Crustacea, Monogononta, Bdelloida) having 14 genera were identified at all sampling stations. The present biological investigation disclosed the variation of physicochemical parameters and their influences on plankton community (phytoplankton and zooplankton) of hilsa sanctuary area with an exploration statistical data output to acquire the insights of the study sites and suggested the suitable hilsa fisheries management action plan for the sustainable management of hilsa fishery.