Fish health aspects in grouper aquaculture

The subfamily Epinephelinae comprises groupers including 159 species under 15 genera. Groupers enjoy a wide distribution in the Eastern Atlantic Ocean and Mediterranean Sea. With increasing demand as luxury aquaprotein, the global production of groupers reached 198,690 ,mt in 2007. In Chinese live-fish markets they fetch a wholesale premium price of US$100/kg. However, the large scale seed production and culture of groupers continue to encounter increasing difficulties, especially with a host of infectious diseases including different viral, bacterial, and parasitic pathogens. Apart from some documented viral problems in Southeast Asia in groupers, little is known about the impact of major diseases that may go beyond direct mortalities and loss in production. Use of chemicals in disease management is discouraged because of their negative impacts to the aquatic environments and strictures passed by importing countries due to consumer reluctance. Besides, frequent use of traditional therapeutics also paves the way for the emergence of disease resistant strains of pathogens. Even most of the available antiviral drugs often lead to the development of viral-resistance coupled with problems of side effects, recurrence, and viral latency. Studies on cloning and growth characterization of immune related genes in groupers are limited. This review presents the currently available prophylactic measures in grouper culture in Asia-Pacific region. It also enlists the recommended health management strategies, which may be applied or further explored for improving health status and to make grouper aquaculture sustainable.