Profile Of Bacterial Composition In Relation To Water Quality Parameters In A Brackish Water Aquaculture System

Abstract

Microorganisms especially bacteria play a vital role in aquaculture system. Naturally occurring bacteria are of both beneficial as well as harmful to the culture organisms. The present study aims at screening the total microbial load and other pathogens to illustrate the common microbes usually present in the aquaculture pond and to understand their role in fulfilling the growth and healthy yield of shrimps. In this context, it is imperative to have regular monitoring of microbial composition in relation to essential water quality parameters for predicting the development of aquaculture industry. This study was carried out in a demonstrate-shrimp aquaculture system of CAS in Marine Biology located at the intertidal region of Vellar estuary. The physico-chemical parameters (Temperature, Salinity, pH, Dissolved Oxygen and Ammonia) were found in the normal range that was suitable for shrimp culture system. The correlation/regression was made between the inter-related parameters in source and pond water to know their influence over others and it was noticed that temperature and salinity (R² = 0.69; R² = 0.75) as well as ammonia and pH (R² = 0.286; R² = 0.601). ANOVA was also made between the source and pond waters for the parameters examined and it was observed that all the parameters between source and pond waters were found insignificant (p > 0.05) except ammonia that showed a significant variation (p<0.05) between the source and pond waters. In the present study, the microbial load was noticed with normal range and not shown any microbial diseases in the cultured shrimp. In the source waters, the TPC was found in the range of 9.9x10^-1.8x10² CFU/ml/10^-3, Vibrio sp was observed in the range of 72-96 CFU/ml, Escherichia coli was found in the range of 102-132 CFU/ml and Staphylococcus sp. was noticed in the range of 36-44 CFU/ml. In the pond waters, the TPC was found in the range of 7.4x10^-1-2.9x10² CFU/ml/10^-3, Vibrio sp was observed in the range of 28-57 CFU/ml, Escherichia coli was found in the range of 44-204 CFU/ml and Staphylococcus sp. was noticed in the range of 18-76 CFU/ml.