Disease changes how fish are raised
Glenwood Springs Correspondent
Vail, CO Colorado
RIFLE ” Whirling disease was first discovered in Colorado in the late 1980s, Rifle Falls Fish Hatchery Manager Dave Capwell said.
And even though the Colorado Division of Wildlife is still battling the disease in many waters around the state and nation, the Rifle hatchery has made gains in breeding a healthy stock of trout on the Western Slope.
Around 2001, whirling disease was eradicated from the Rifle Falls Fish Hatchery eradicated, Assistant Manager Mark Jimerson said.
One reason was a switch to using spring water rather than Rifle Creek water.
“We isolated the spring water from Rifle Creek so that none of the contaminated creek water gets into the facility,” he said.
The change ensured a clean water source to raise healthy fish crops.
“A lot of hatcheries nationwide were affected by the disease,” Capwell said. “But today, we know for sure that the fish here are clean from everything.”
Twenty-two states nationwide have reported infected fish, according to the Whirling Disease Foundation’s Web site.
The Rifle hatchery started an “isolation facility” mostly used for raising native cutthroat trout. The facility is separate from the rest of the hatchery and uses its own water supply from another natural spring.
The fish are raised and sent out for disease testing.
Species are separated from one another at the hatchery to prevent the spread of disease.
The hatchery had to quit using its original storage ponds because the soil was ” and still is ” contaminated with whirling disease, Capwell said.
Instead of destroying infected fish, the hatchery tries to find other uses for them.
“Normally we don’t destroy them,” Jimerson said. “We will put (infected) fish into whirling disease positive waters. We avoid destroying them if we can.”
The isolation facility has improved the way the Division of Wildlife breeds and raises fish nowadays.
For instance, Capwell said that wild fish used for breeding have to be tested every three years. Testing requires a sample of 60 fish. In some instances, Capwell said, there may only be 40 or 50 fish inhabiting a certain lake or river system.
The isolation facility allows them to bring in 10 fish, breed and raise a crop for testing, then release the original 10 back into the river or lake.
“It doesn’t make sense to take the 50 out of the drainage and test them,” Capwell said. “Out of that 10 we can produce 4,000 and test from that section.”
If the tested fish are infected the Division of Wildlife can eliminate the rest of the group from the river system or lake.
If the tested fish are determined to be disease free, they can be stocked and the rest of the crop may even be used to re-establish a population in a barren drainage, Capwell said.