Disease surveillance of cultured marine fish in the North of Bali, Indonesia
Abstract A regular surveillance of marine fish diseases was conducted from March to November 2019 in order to determine the occurrence time of the diseases within the mariculture centre of the North of Bali, Indonesia. The monthly surveillance was conducted by collecting 15 fish samples from each of the three hatcheries in Gerokgak and Penyabangan villages and of the two floating net cages in Pegametan Bay, Sumberkima village. Bacterial concentrations were grouped into 4 categories including low, moderate, high and very high. Surveillance data were analyzed using bivariate descriptive statistical methods. The results showed some important findings. First, the results of the study showed that NNV infection was found during the transitional seasons in March to June and September to November. Parasite infection were more frequent observed in fish with high and very high bacterial population. Second, high concentration of total bacteria in fish-feces occurred throughout the year. The prevalence of NNV infection and bacterial populations at the high to very high concentration were mostly occurred in the cultured fish in hatcheries at the size of 1-10 g, while in cultured fish at the net cages were mostly occurred at the size of > 50 g.