Aquaculture disease and health management.

Disease problems constitute the largest single cause of economic losses in aquaculture. In 1988, channel catfish producers lost over 100 million fish worth nearly $11 million. Estimates for 1989 predict even higher losses. The trout industry reported 1988 losses of over 20 million fish worth over $2.5 million. No data are available on losses sustained by producers of shellfish. Bacterial infections constitute the most important source of disease problems in all the various types of production. Gram-negative bacteria cause epizootics in nearly all cultured species. Fungal diseases constitute the second most important source of losses, especially in the culture of crustaceans and salmon. External protozoan parasites are responsible for the loss of large numbers of fry and fingerling fin fishes and are a cause of epizootics among young shellfish. The number of therapeutants approved by the Food and Drug Administration is limited. Research to support the registration of promising therapeutic agents is urgently needed.