Walt Donaldson, aquatics section chief, said the agency is committed to stocking healthy fish, and "good science requires that we not stock infected fish. We discovered the problem, notified the Fish Health Policy Board and are committed to sustaining healthy fisheries."

Whirling disease affects trout and salmon and results in deformities and neurological damage that cause the fish to swim in circles.

Whirling disease was first found in a private hatchery in Loa in 1991 that was owned and operated by the family of former Utah Gov. Mike Leavitt. The family has since gotten out of the fish-ranching business.

Since that time, the disease has spread to a large number of public waters, including such popular areas as Porcupine, Causey, Logan River, Provo River, Weber River, Ogden River and Otter Creek. It has also been found in the Green River above Flaming Gorge and more recently in waters on the south slopes of the Uintas, including the Duchesne River and waters around Altamont.

It was also reported last year that all but one of the state's 10 commercial fish growers tested positive.

The disease starts with a parasite. It is spread by small worms that eat the parasite that in turn are eaten by fish. The parasite causes, among other things, a curving of the spine in fish, which causes them to swim in circles — or whirl — and eventually die. The disease does not affect humans.

---

E-mail: grass@desnews.com