Iron River NFH Efforts to be Disease Free
BY CAREY EDWARDS, IRON RIVER NFH
Furunculosis (pronounced fur-unc-you-low-sis) is a bacterial disease primarily found in cultured salmonid and warm water species. It is found widespread in natural waters. Diseased fish appear lethargic, go off feed and display clinical signs such as exophthalmia (bulging eyes), hemorrhagic fins, and furuncles (open boil-like sores). The pathogen is usually transmitted as the result of contact with diseased or carrier fish but can also occur via water passed from one contaminated water supply to another (tank to tank). Fish may be carriers of the disease without showing any clinical signs, which is why hatchery fish are biannually tested by the La Crosse Fish Health Lab.
The disease positive classification can impact the U.S. Fish & Wildlife Service’s ability to meet stocking goals with its many partners including state and tribal agencies because some states have regulations regarding the transport of eggs and fish from positive facilities. A priority for Iron River National Fish Hatchery has been to maintain a disease free status.
vaccine and moved back into the raceways. Credit: USFWS
Small brood fish (approximately two grams in weight) are immersed in a dip while larger brood fish receive an injectable version of the vaccine. This is the fourth year that the vaccine has been implemented with adults being injected in mid-July and the final immersion of juveniles in early September. It is hoped that the early vaccination process will be part of a successful biosecurity plan at the Iron River National Fish Hatchery to help maintain a disease free status.