College of Fisheries, Mangaluru, has detected a rare viral disease, Red Sea Bream Iridovirus (RSIV), in marine fish found in Udupi region.
According to A. Senthil Vel, professor and Dean (Fisheries) of the college, it has been detected in the Asian Sea bass (marine fish) for the first time.
“The RSIV, earlier unknown in Indian waters, was for the first time identified and isolated in the country,” he said in a release on Thursday. Mr. Senthil Vel said fish farmers in Udupi region had informed the college on the mortality of Asian Sea bass (Lates calcarifer) grown in the cages. The affected fishes exhibited abnormal behaviour and clinical signs, including slow movement, lethargy, reduced feeding, and erratic movement along the sides of the cages.
Pathologists from the college analysed the samples collected. The laboratory test included microscopic examination, histopathology and molecular-based assays. “It was found that the Asian Seabass were infected by RSIV,” the release said.
The RSIV was first observed in Japanese-cultured red sea bream farm in the 1990s. More than 30 marine and brackish water fish species such as sea bass, grouper, and red sea bream etc. are known to be susceptible to this virus.
This virus can causes mortality up to 100% depending on host fish species, size, age, water temperature, and other culture conditions. The main target organs for RSIV are spleen, kidney, heart, intestine, and gill. “Since RSIV is a emerging virus in Indian waters, proper management measures have to be undertaken to mitigate its spread,” Mr. Senthil 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 the progress. However proper scientific management practices can be adopted to control and prevent the spread. It included stocking pathogen-free fish, implementing hygiene practices on farms, and avoiding practices that can decrease water quality such as overcrowding and overfeeding.
Unfit for consumption
Mr. Senthil Vel told The Hindu that fish affected by RSIV is not advised for human consumption. The college is yet to study on what health issues humans could face if affected fish are consumed.
The team of pathologist of the college who detected the disease comprised Girisha S.K., Puneeth T.G, Nithin M.S., Naveen Kumar B.T., Ajay S.K., Vinay T.N., Suresh T., Venugopal M.N., and Ramesh K.S. from the Department of Aquatic Animal Health Management at the college.
If fish farmers find any of the symptoms mentioned, they can contact the college on 0842-2246384.
