The department of Aquatic Animal Health Management in the College of Fisheries, Mangalore in India has detected a new viral disease in Asian sea bass, hitherto unknown in Indian waters.
The fish were infected with red sea bream iridovirus (RSIV), which was first observed in a Japanese cultured red sea bream farm in the 1990s, The Times of India reported.
In the year 2018 through to 2019, fish farmers in the Udupi region in the southwest state of Karnataka experienced mortalities of Asian sea bass (Lates calcarifer) grown in cages. The infected fish showed abnormal behavior and clinical signs including slow-moving, lethargy, reduced feeding, and erratic movement along the sides of the cages, said A. Senthil Vel, Professor and Dean of Fisheries for Karnataka Veterinary at the Animal and Fisheries Sciences University, Mangalore.
Laboratory tests by pathologist from the college indicated that Asian sea bass were infected by RSIV. More than 30 marine and brackish water fish species such as sea bass, grouper fish, and red sea bream are known to be susceptible to this virus. This virus, which mainly targets the spleen, kidneys, heart, intestines, and gills, can cause mortality up to 100 percent depending on host fish species, size, age, water temperature, and other culture conditions.
Vel said further studies are being carried out in the college and the process of preparing preventive measures for mitigation of the virus is in progress. He cautioned that proper scientific management practices should be adopted to control and prevent the spread of RSIV, including such stocking pathogen-free fish; implementing hygiene practices on farms; and avoiding practices that can decrease water quality such as overcrowding and overfeeding.
The College of Fisheries, Mangalore, is a fisheries education and research institute established in 1969. It is now part of the Karnataka Veterinary, Animal and Fisheries Sciences University in Bidar.
The college has been carrying out a disease surveillance program under the “National Surveillance of Aquatic Animal Disease” project in both fresh water and brackish water cultured fishes. The program was initiated by the National Bureau of Fish Genetic Resources, Lucknow. The prime objective of the project is to create awareness about emerging aquatic animal diseases and preventive measures among the fish farmers in the regions where fish culture and shrimp farming are being carried out in Karnataka through passive and active surveillance, the Time of India said.
Photo courtesy of Faiz Zaki/Shutterstock
