Qualitative and quantitative analysis of phytoplankton in culture pond of Noakhali district, Bangladesh

A study was conducted on qualitative and quantitative analysis of phytoplankton in cultured ponds of two fish farms of Noakhali district, Bangladesh from 15 September to 15 November 2012 to identify and estimate the abundance of phytoplankton in various culture ponds of two fish farms. Analyses of phytoplankton samples recorded a total of 4 classes phytoplankton viz.; Bacillariophyceae, Chlorophyceae, Cyanophyceae, Euglenophyceae. Out of 21 phytoplankton genera identified, 5 belong to Cyanophyceae, 7 to Chlorophyceae, 5 to Bacillariophyceae and 4 to Euglenophyceae. Among the identified genera, Euglena, Microcystis, Eurolena were found to be dominant genera. Total phytoplankton abundance was varied from 36×105 cells/L to 94.92×105 cells/L in the experimental ponds. Among all experimental ponds, Chlorophyceae was found dominant (44.4×105 cells/L). Second dominant group was Euglenophyceae (39.6×105 cells/L) observed in pond-1 of Bismillah Agro Production (BAP). Total phytoplankton densities were recorded 47.82×105cells/L and 51×105 cells/L in pond-1 and pond-2 of Subarna Agro Based Initiative (SABI) respectively. In BAP, total phytoplankton densities were recorded 94.92×105cells/L and 36×105 cells/L in pond-1 and pond-2 respectively. Management technique and water quality parameters were also studied during study period namely water temperature, conductivity, salinity, transparency, dissolve oxygen and pH. The present study reveals that phytoplankton species are variable among the culture ponds and their density is also variable. The information provides for more research to compare water quality and pond phytoplankton characteristics in earthen aquaculture systems with and without fish stocking. Further studies on the seasonal changes of water quality parameters and its effects on phytoplankton production in the fish ponds and all year extended monitoring is recommended in future studies.