Whirling disease has been confirmed in rainbow trout in the Watauga River in the Banner Elk area, and biologists are concerned that the disease could spread to other trout populations. 

Biologists have suspended trout stockings until they can test hatchery fish to ensure they’re disease-free — even though the diseased fish came from a trout stream that was not stocked with fish raised by the N.C. Wildlife Resources Commission. 

The disease, caused by a parasite, affects all species of trout and salmon, with rainbow and brookies — especially younger fish — appearing to be the most susceptible. Brook trout, North Carolina’s only native species, lives mainly in colder waters — the parasite’s preferred habitat. 

The Commission is also testing trout from the Watauga River, its tributaries and area aquaculture operations to determine how far the disease has spread. 

The disease, now present in more than 20 states, is spread mainly through infected fish and fish parts but can also be transmitted by birds and anglers who transfer the parasite on their equipment. 

Though there is no cure for the disease, the presence of whirling disease isn’t necessarily a death knell for fish populations. In other states, the disease has been present for decades, and impacts on both wild and stocked trout were not as devastating as feared. 

Whirling disease damages nerves and cartilage in the species it affects, which can cause fish to swim in a circular, tail-chasing pattern — hence the name of the disease. 

Report sightings of trout with deformities and strange swimming behaviors at www.ncwildlife.org/Fishing/WhirlingDisease/WhirlingDiseaseContactForm.aspx.