Sunday, November 26, 2000
Yampa A successful end to a two-year cleansing project at Finger Rock hatchery means trout raised there now are free of the whirling disease parasite.
The third and final test in a 16-month period performed by the Colorado Division of Wildlife to detect whirling disease was recently finished at Finger Rock. It came up the same as the first two: negative.
"It officially makes Finger Rock a whirling disease negative hatchery," DOW spokesman Todd Malmsbury said.
Finger Rock is just south of Yampa. It is now the seventh of eight hatcheries that has tested negative for the parasite that causes whirling disease, thanks to a $13 million effort to modernize the hatcheries, according to the DOW.
River water at Finger Rock infected with the parasite was stopped from going through the hatchery. Instead, ground water is being used at the hatchery to grow the fish.
Also, earthen ponds at Finger Rock were taken out of the fish-raising process. All fish are now reared in concrete pools where the parasite's host, the tubifex worm, can't survive. After the ground water was secured, the unit was disinfected and new fish eggs were brought in to start over.
"Our water is so much cleaner and clearer since we enclosed the spring water," said Dan Doering, who works at the hatchery.
Because of whirling disease, most of the fish from Finger Rock were released in waters on the Front Range that already had the parasite in them.
"We should now be able to stock some fish in Western Slope waters," Doering said.
The DOW allows only whirling-disease-negative fish to be stocked in most streams and lakes on the western slope, he said
Finger Rock is expected to produce around 280,000 WD-negative, 10-inch, catchable-size rainbow trout for stocking in 2001.
Those fish will be key for the DOW, division spokeswoman Babs Brockway said. In a Wildlife Commission meeting earlier this month, which is the entity that makes executive decisions for the DOW, commissioners voted to end stocking fish with whirling disease in nearly all waters in Colorado by 2003, Brockway said.
Last year, DOW biologist concluded that the parasites were increasing in number in streams where they already existed because the DOW was stocking fish that were infected.
"That's why the commission decided not to stock the WD-positive fish any more," Brockway said. "They want to stop the disease from spreading."
The goal is to eliminate whirling disease from Colorado waters, she added.
Whirling disease is a parasitic infection of trout and salmon that exhibits a complex life cycle including two hosts the fish and a small worm found in aquatic environments. Fish heavily infested with the parasite can become deformed or exhibit the erratic tail-chasing behavior from which the disease gets its name. Eventually, heavily infected young fish may die. It was first discovered in Colorado in the mid 1980s and eight hatcheries in the state still test positive.
The $13-million renovation and modernization of the state's hatcheries include Mount Ouray, Salida isolation, Buena Vista, Durango, the Bellvue production facility, the Research Hatchery, Mount Shavano, Roaring Judy, Rifle and Pitkin. Of these hatcheries, construction has been completed on all but Roaring Judy, Rifle and Pitkin.
"It was a thorough task that was painstakingly done," Doering said of the work done at Finger Rock. "But the results are positive, with negative (test) results."
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