S. Boonyaratpalin
Shrimp farming in Thailand has been practiced for the last 80 years. The farming system has evolved from extensive to semi-intensive, and further to intensive and super-intensive. Thailand has been the leading country in shrimp aquaculture production in the world since 1991. This position can be attributed to many factors that favor marine shrimp farming development. Among these are suitable sites, the long experience in aquaculture among Thai farmers, the small-scaIe structure of the industry which enables closer farm supervision and management, control of environment impacts, strong promotion by the government, and other favorable conditions.
However, its rapid development has also created adverse on the coastal environment, about which the Royal Thai Government has tried various measures to mitigate the adverse effects with the view of promoting a sustainable shrimp culture industry. One of these is the prevention and control of shrimp diseases which have been linked to deterioration in the culture environment.
Diseases in cultured black tiger shrimp in Thailand are caused mainly by five groups of organisms. These include viruses, bacteria, fungi, protozoa and metazoa. Among these, the yellow-head and white spot viruses are considered highly virulent in cultured black tiger shrimp and have caused severe losses in cultured shrimp. On the other hand, monodon baculovirus (MBV) and hepatopancreatic parvo-like virus are associated with healthy shrimp.
Vibriosis is a disease caused by bacteria of the genus Vibrio (Vibrio harveyi, V. parahaemolyticus, V. vulnificus, V. anguilarum, V.alginolyticus). Bacterial diseases are infectious both in the hatcheries and growout farms and the incidence of antibiotic resistance in the isolated strains is high. Diseases caused by fungi, protozoa and metazoa are not significant compared to bacterial and virus infections. Prevention strategies include measures to control virus outbreak such as increasing water reservoirs, eradicating virus carriers (such as wild shrimp, crab, etc.), production of healthy seed, and others. The use of probiotics in pond management is gaining attention as a means to prevent or minimize bacterial diseases.
(Department of Fisheries, Kasetsart University Campus, Ladyao, Jatujak, Bangkok 10900, Thailand)