Associated Press Signs of whirling disease found
SALT LAKE CITY - Signs of whirling disease have been found at the Midway fish hatchery and it will mean the loss this season of more than 300,000 catchable rainbow trout - 21 percent of the catchable fish stocked in Utah each year.
Traces of the parasitical disease were detected through new DNA testing. Standard tests continued to be negative, the state Division of Wildlife Resources said Tuesday.
It is the first time the disease has been found in a state-operated hatchery in Utah.
The affected fish were found in dirt raceways at the lowest portion of the hatchery, closest to Deer Creek Reservoir, where the parasite recently was confirmed.
It was believed the disease was introduced at the hatchery by fish-eating birds or other predators.
The state Fish Health Board agreed Monday to have 220,000 7- to 9-inch fish, which did not test positive for the disease, stocked in Jordanelle Reservoir, which also has tested positive for the parasite, said Tom Pettengill, DWR sport fisheries and aquatic education coordinator.
Another 600,000 2-inch fish will be released at the Jordanelle and Deer Creek reservoirs, but, because of their small size, only a small percentage are expected to survive and grow large enough to be caught.
Most of the catchable fish from Midway are stocked in northern, central and northeastern waters.
To lessen the impact on these waters, some of the fish that would have been stocked in southern Utah from other hatcheries will be put in the northern waters.
Whirling disease is caused by parasites that attack cartilage in the head and spine of young trout, deforming the fish. In advanced stages, the nervous system is affected and fish swim in circles. It is not harmful to humans.
The disease was first discovered in Utah in 1991 in a hatchery in Wayne County.