State Trout Hatcheries To Resume Stocking Fish After Testing Negative for Whirling Disease, Biologists Continue To Sample Waters In Watauga River Basin

Last Updated on August 19, 2015 6:53 pm

The N.C. Wildlife Resources Commission resumed stocking Hatchery Supported trout waters today after receiving confirmation that trout from Armstrong State Fish Hatchery in Marion and Setzer State Fish Hatchery in Brevard tested negative for whirling disease, a disorder affecting trout.

Whirling disease affects fish in the trout and salmon family. The disease, caused by the microscopic parasite, Myxobolus cerebralis, damages cartilage and skeletal tissue in a fish, causing it to swim in a whirling motion. While often fatal to juvenile fish, the disease does not infect humans or pets, and eating an infected fish is not known to cause any harmful effects.

The Commission will not retroactively stock Hatchery Supported locations that did not receive fish during the hatchery-testing period due to recent drought conditions and concerns of high water temperatures at those locations.

The Commission also has implemented safeguards to reduce the chance of the parasite being transported to agency trout hatcheries.

“We are initiating disinfection protocols for all gear and stocking trucks returning from stocking runs before they enter the hatchery,” said David Deaton, fish production supervisor. “Additional security measures are being developed to minimize the potential introduction or spread of the disease into other trout waters or our production facilities.”

Whirling disease was confirmed in rainbow trout collected from the Watauga River on July 28 — the first occurrence of it in North Carolina. Commission biologists sampled trout from its two trout hatcheries, Armstrong and Setzer, and sent them for testing at the fish disease laboratory at Auburn University in Alabama.

Commission biologists are continuing to sample waters in the Watauga River basin to determine the extent of whirling disease within the basin. They expect test results within two weeks.

Commission biologists also have instituted a gear-disinfection protocol to ensure the parasite is not spread to new locations when staff is in the field collecting trout and sediment from streams that could potentially contain the whirling disease parasite, tubifex worms or gill lice.

Help Prevent the Spread of Aquatic Nuisance Species

The discovery of whirling disease, along with a new gill lice species in rainbow trout this summer, underscores the importance of preventing the spread of aquatic nuisance species, because once established in a body of water, they are almost impossible to eradicate. The Commission encourages the public to help prevent the spread of whirling disease, gill lice and other harmful pathogens by cleaning and drying equipment, clothing or anything else that comes into contact with water. In addition, no one should move live fish or aquatic wildlife from one body of water to another without first obtaining a permit from the Commission.

Anglers are asked to contact the Commission at if they observe deformities, strange swimming behaviors, or other signs of disease in trout. Anglers who see trout with parasitic gill lice, which look like tiny grains of white rice typically on the gills, can also share their observations at

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