Mass mortality of larval and juvenile hatchery-reared halibut (Hippoglossus hippoglossus L.) associated with the presence of virus-like particles in vacuolated lesions in the central nervous system and retina.

Grotmol, S., Totland, G.K., Kvellestad, A., Fjell, K. and Olsen, A.B.
Bull. Eur. Ass. Fish Pathol.
Commercial production of halibut (Hippoglossus hippoglossus L.) is a steadily growing industry in Norway despite a number of problems that give a high mortality in the larval and juvenile stages. The high mortality has been causally connected to nutritional factors in start feeding and weaning periods. In addition, mortality has also been caused by defined bacterial and viral infections such as vibriosis and IPN.

During the summer of 1995 high mortality occurred in two production units in Norway. In one production facility the larvae were extensively reared in floating bags in a marine lagoon. The second facility was an intensive land-based unit. This report describes a nodavirus-like agent associated with vacuolating encephalomyelopathy and retinopathy found in halibut larvae and juveniles from both facilities.
Unspecified source