White faeces disease and abundance of bacteria and phytoplankton in intensive pacific white shrimp farming

Shrimp farming intensification has impacted various diseases; one of these is white faeces disease (WFD). Factors that cause WFD remain unknown. The research analysed phytoplankton and bacteria abundance and community composition in intensive Pacific white shrimp farming during an outbreak of WFD. Composite sampling was conducted. Fifty litres of water samples were taken and filtered using a plankton net. Filtered water was preserved in bottle samples by adding 8–10 drops of Lugol solution and labelled. Bacteria were enumerated by total plate count. Symptoms began to appear on the 49th day of culture, which are the size of the shrimp that is smaller than the normal size, the soft carapace condition, the intestinal tract that is not filled, and the appearance of spots of white faeces on the surface of the water. The results showed that the number of Vibrio in the water and shrimp intestines infected with WFD was higher than the abundance of bacteria in the culture water and the normal intestine of shrimp. There were four phytoplankton classes: Bacillariophyceae, Chlorophyceae, Cyanophyceae and Dinophyceae. Phytoplankton abundance increased significantly in the WFD‐infected pond.