Following confirmation of whirling disease in rainbow trout from the Watauga River in North Carolina, biologists with the N.C. Wildlife Resources Commission are concerned about potential significant impacts the disease may have on other trout populations, in particular native brook trout populations.
The disease, which is caused by a parasite, affects all species of trout and salmon; however, rainbow and brook trout, two species found in North Carolina waters, appear to be the most susceptible. Brook trout is the only trout species native to North Carolina, and it lives mainly in colder waters, which is also the preferred habitat of the parasite.
Despite their concern, biologists acknowledge that the presence of whirling disease doesn’t necessarily equate to a dramatic loss of fish, given that other states where the disease has been present in waters for decades have been able to manage the disease so that impacts on both wild and stocked trout haven’t been nearly as devastating as previously thought.
Biologists, however, aren’t taking a wait-and-see approach to how whirling disease will impact North Carolina trout populations. They are taking every precaution to limit the spread of the disease now.
While the diseased fish came from a trout stream that was not stocked with trout raised at one of three Commission-owned hatcheries, Commission staff have suspended trout stockings until they have tested hatchery fish and determined that they are free of the disease.
Commission staff are currently collecting trout from the Watauga River and tributary streams to test for whirling disease and to determine its distribution in the watershed. The N.C. Department of Agriculture and Consumer Services and N.C. State University are working with the Commission to sample commercial aquaculture operations in the area where the infected trout were found.
To learn more about whirling disease and to report signs of disease in trout visit: www.ncwildlife.org/whirlingdisease.
source: North Carolina Wildlife Resources Commission