A REVIEW OF VIRAL DISEASES OF CULTURED SHRIMP

The culture of aquatic organisms has been growing steadily in recent y ears. Many economically important marine species such as shrimp, lobst er, clams and oysters are farmed, and several techniques have been dev eloped to improve their rate of growth and production. Basic veterinar y knowledge of animal nutrition, physiology and pathology can be appli ed to aquatic culture. This review focuses on the medical aspects of s hrimp culture, with special emphasis on the recognition, diagnosis and prevention of viral diseases affecting shrimp farming. In 1990, shrim p farming produced more than 25% of all the shrimps on the world marke t (2.6 million tonnes) (Rosenberry, 1991). The total revenues for this production amounted to 6 billion dollars in Japan and the United Stat es alone. Around the world there are 18 000 shrimp farms, 3500 hatcher ies and more than 1 million ha of shrimp ponds. Traditional shrimp fis hing is threatened by over-fishing, pollution and fuel prices. Since f ishing soon will be unable to satisfy world demand, shrimp farming is becoming increasingly important (Tseng, 1987). There are many species of cultured penaeid shrimp: the family Penaeidae (suborder Natantia) h as 318 species belonging to 13 genera. Approximately 80 species of thi s family are exploited by commercial fisheries or farming. Within the family Penaeidae, the genus Penaeus is commercially the most important (Brock et al., 1983).