Whirling Disease: Fly Fishermen and Guides take extra care in the Boone Area

Alarming excerpt from article in Watauga Democrat:

“Biologists have confirmed the presence of two parasites affecting trout in the Watauga River in Foscoe — including the first occurrence of whirling disease in North Carolina.
The N.C. Wildlife Resources Commission said Wednesday that whirling disease was confirmed in rainbow trout collected from Watauga River near Foscoe in Watauga County.
Whirling disease affects fish in the trout and salmon family with rainbow and brook trout, two species found in North Carolina waters, being the most susceptible.
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.
Although the infected trout were collected from a section of the Watauga River well upstream of public trout stocking locations, the commission has proactively suspended stocking fish raised at its three trout hatcheries until it can confirm that hatchery trout are free of the disease.
Doug Besler, WRC regional fisheries supervisor for the mountain region, said an angler observed deformities in the fish and alerted the commission. Biologists then collected 20 trout, two of which were confirmed to be infected with whirling disease by a lab at Auburn University, according to Besler.
Based on the location and size of the fish, the WRC believes the infected fish are wild trout, he said.
Biologists also determined that another parasite is affecting area trout.
“We found gill lice on some rainbow trout as well,” said Besler.
Gill lice were first reported in North Carolina late last year — on brook trout in Macon County. Since then, he said, the tiny white crustaceans have been found on trout in the Pigeon River, the Boone Fork in Watauga County and now the Watauga River in Foscoe.
“They’re both definitely a concern,” he noted. “Any animal that gets a large parasite load has less energy for its own needs, and it affects the fish’s ability to stay healthy and makes it vulnerable to other diseases.”
The parasite that causes whirling disease was first discovered in Pennsylvania in 1956, according to the WRC. In some states, whirling disease has been observed in isolated cases and has had little impact, while in other states, such as Montana and Colorado, the impacts on trout populations have been more pronounced.
This is the first time whirling disease has been confirmed in the Southeast in the wild, Besler said.
“There’s a lot of unknowns at this point. We don’t know what will happen,” he said. “We are hopeful that we will not see large-scale impacts in North Carolina.”
While gill lice is spread from animal to animal, the spores causing whirling disease can remain viable in stream sediment for up to decades.
But “trying to keep people (away) from bodies of water is not practical,” said Besler. “Other states have not tried to do that.”
Instead, the commission encourages the public to help prevent the spread of the parasite that causes whirling disease 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.
As one of many precautionary measures, staff is collecting fish from commission trout hatcheries and sending them to the Fish Disease Laboratory at Auburn University for testing.
“So far, we have no indications that trout at any of our hatcheries are infected with whirling disease, but we are being extra cautious and having fish tested before we resume stockings,” Besler said in a statement. “We hope to have test results back within the next few weeks and once we rule out whirling disease infection at our production facilities, we will resume planned trout stocking operations.”
Besler said the suspended stockings would affect 14 locations in 12 counties, but not Watauga, which had no stockings scheduled in August.
Watauga’s last stocking was on July 22, he said.
Commission staff will also collect trout from the Watauga River and tributary streams to test for whirling disease and to determine its distribution in the watershed.
In addition, commission staff is working closely with N.C. Department of Agriculture and Consumer Services and N.C. State University to sample commercial aquaculture operations in the area where the infected trout were found.
Anglers are asked to contact the WRC if they observe deformities, strange swimming behaviors, or other signs of disease in trout.
“We’re trying to put info on there on what anglers can do to help us,” Besler said. “Take a picture and send us the coordinates.”
For a list of frequently asked questions on whirling disease, to learn more about whirling disease and its effects on trout, and to report signs of disease in trout visit www.ncwildlife.org/whirlingdisease. The page will be updated as test results become available.”

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