ABSENCE OF INFECTIOUS HEMATOPOIETIC NECROSIS VIRUS (IHNV) IN NEW-ZEALAND SOCKEYE-SALMON, ONCORHYNCHUS-NERKA

A study was undertaken of wild and hatchery stocks of freshwater resid ent sockeye salmon for infectious haematopoietic necrosis virus (IHNV) in New Zealand. From 1988 to 1991, 306 fish were sampled at egg colle ction from a broodstock reared entirely in captivity. Kidney and some ovarian fluids from 89 wild fish (kokanee) were removed and frozen at -70-degrees-C after they spawned in the Waitaki River catchment. Mater ial from the samples was inoculated into tissue culture cell lines of Epithelioma papulosum cyprini (EPC) and chinook salmon embryo (CHSE-21 4) cells. No IHNV was detected in any of the samples, suggesting that sockeye salmon stocks in New Zealand are free of detectable IHNV.