Increased Occurrences of Infectious Hematopoietic Necrosis Virus in Fish at Columbia River Basin Hatcheries: 1980-1982

摘要

From 1980 through 1982 a significant increase in isolations of infectious hematopoietic necrosis virus (IHNV) from hatchery salmonids in the Columbia River basin was documented. Losses of cultured salmonids to the disease increased more than twentyfold from 1980 to 1981, and mortality-related losses were almost forty times that of 1980 levels during 1982. Extreme modifications of conventional hatchery practices have been adopted at certain locations where viral-infected stocks of fish must be used as a source for eggs.