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Mad Fish – 900,000 Whirling Disease Trout Exterminated
By Caleb Warnock Daily Herald
From Patricia Doyle, PhD
From ProMED-mail
4-29-5An outbreak of whirling disease has been discovered in the Springville fish hatchery, requiring that 900 000 fish, mostly rainbow trout destined for lakes and ponds around the state, be destroyed.
Whirling disease spores were discovered in routine tests of 60 fish in early April 2005, said Joe Valentine, Division of Wildlife Resources aquatic culture supervisor. Additional tests found more infected fish, and DNA tests confirmed the spores to be whirling disease on Wednesday.
Wildlife officials announced in July 2004 that they would close the Springville fish hatchery to the public because of fears of spreading the disease through mud on shoes, for example. The disease causes fish to spin and deforms them, causing them to eventually starve to death.
Both Hobble Creek and Provo River are known to be infected with the disease, “and we’re right in between,” Valentine said of the hatchery. The disease was likely spread to hatchery fish by birds or mammals that had been in one or both of those streams.
The news is a double blow to state wildlife officials. The Springville hatchery is the 3rd in Utah to suffer an outbreak of the disease, and a 4th hatchery is being reconstructed, leaving only 6 of the state’s 10 hatcheries to produce stock fish.
Recovering from the outbreak will cost at least $2 million, Valentine said. A water treatment system sensitive enough to remove all disease spores must now be built, and all raceways where the fish live must be sterilized after the fish are destroyed.
The financial impact is also escalated because the fish to be destroyed are worth at least $200 000, he said. They include 250 000 9- to 11-inch mature fish that were ready to be stocked in lakes and streams this year.
Fish from the Springville hatchery are taken to streams, lakes and reservoirs around the Wasatch Front, including Spring Lake south of Payson.
Once a hatchery has been infected, the recovery process is not fast. “We haven’t gotten one back into full production,” Valentine said.
The Midway hatchery was hit in April 2000, he said. Before the outbreak, it was home to 150 000 fish; after spending $800 000 to drill 3 new wells to supply the hatchery with disease-free water, it now supports only 20 000 fish.
Another $7-8 million is needed to build new raceways before production can be increased to former levels. “We just don’t have the money,” Valentine said.
An outbreak at the Mammoth hatchery was discovered in 2002, causing all 70 000 fish there to be destroyed. The hatchery is empty today as crews struggle to install a water sterilization system that is only 1/3 the size of what Springville will now require.
“It takes a long time to get a hatchery back, and a lot of money,” he said.
Officials are hoping to stretch supplies from existing hatcheries, he said.
“This is the 3rd time we’ve had to come up with fish in a shortfall,” he said. “With more water at other hatcheries this spring, they can produce more.”
Whirling disease was first found in Utah in 1991 in a private hatchery, reportedly owned by the family of former Gov. Mike Leavitt. The disease is believed to have originated in the United States after infected frozen rainbow trout were transported here from Denmark in the 1950s.
Patricia A. Doyle, PhD
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