Mariculture, especially cage farming of finfish in marine and coastal waters is a highly
economically viable culture system in the world, due to its high production and export
market value. Recirculation technology is emerging in the marine aquaculture industry
due to its unique form of fish farming and is gaining lot of attention all over the world.
High density intensive culture of fish in indoor tanks, with a controlled system will be
highly beneficial compared to the traditional method of growing fish in open marine waters
(cages/raceways/pens etc), where control of environmental conditions is not possible. RAS
with proper management will have several advantages such as year round culture, harvest,
flexibility in species selection and site of culture, conservation of water, improvement in
water quality through filtration and recycling of clean water, reduction in stress and high
survival and production of fish as compared to other mariculture systems. But high density
production in a confined volume without proper management will always result in disease
outbreaks, which leads to economic loss in a short span of time. Consideration of good
health management is the most critical part of successful and efficient operation of
recirculating systems. Occurrence of diseases in recirculating systems varies between the
species and is mainly due to the lack of management practices. In recent years, prevalence
and spread of diseases has been increasing enormously in mariculture systems which are
caused by a wide range of infections, including bacteria, viruses, fungi, protozoan and
metazoan parasites; nutritional and environmental problems etc. Many of the marine finfish
are encountered with many viral, bacterial and parasitic infections during the culture period,
due to several environmental stress conditions and also through horizontal transmission.
Hence, a thorough knowledge on diseases and pathogen profiling, surveillance and
monitoring programmes and also development and implementation of preventive protocols
as better management practices of RAS farming, is the need of the hour. Major common
diseases encounter in cultivable marine fish and their management practices are mainly
discussed in this chapter
