DOW clears Leadville hatchery as whirling disease-free | AspenTimes.com

DOW clears Leadville hatchery as whirling disease-free

Christine Ina Casillas
Leadville correspondent

Ed Stege, the U.S. Fish and Wildlife Service manager at the Leadville National Fish Hatchery, empties cutthroat trout fingerlings into a bucket for weighing. (Courtesy Leadville Chronicle)

Aspen, CO Colorado

LEADVILLE ” Leadville’s National Fish Hatchery recently was certified free of whirling disease by the Colorado Division of Wildlife.

With news of being free of the disease, the fish hatchery now can provide fish to the upper Fryingpan-Arkansas reservoirs, support recovery of endangered fish in the Colorado River and establish a greenback cutthroat broodstock.

“This has a large economic impact on the local economy, probably in the millions of dollars,” said Carlos Martinez, fishery biologist at the Leadville National Fish Hatchery. “There’s no telling to what extent this has on the economy.”

The disease was first discovered at the hatchery in 1995.

“The discovery of whirling disease prompted the possible closure of the fish hatchery,” Martinez said. “The Leadville Fish Hatchery was very much in danger of closing, and it would have hurt the local economy quite a bit … there’s so much history here. People use our trails to head up toward Mount Massive. There’s cross-country skiing, snowshoeing, hiking … there is no knowing to what extent we could have been hurt by this disease.”

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By state law, fish hatcheries are not allowed to produce any whirling disease-positive fish, Martinez said. When the disease was first discovered in 1995, the hatchery implemented a new state-of-the-art water treatment plant and eliminated the use of earthen-bottomed rearing units.

The hatchery implemented the water treatment system in June 2004. The system is designed to remove or inactivate a disease called Triactinomyxons from the water supply. The water treatment system is the first of its kind used in a mass-production rearing facility to rid incoming water of the disease. The technology uses a combination of filters and ultraviolet light reactors designed to treat the water before it enters the hatchery operation.

“Obviously it worked or things would not be going so well for us now,” Martinez said.

Before it was cleared, trout from the fish hatchery could be stocked only in lower-elevation, whirling disease-positive waters ,where they still contributed to recreational fishing but did not further the spread of whirling disease.

Whirling disease was first introduced to the United States from Europe in the 1950s.

“The disease is caused by a metazoan parasite that penetrates the head and spinal cartilage of fingerling trout disrupting the equilibrium of the fish, causing them to swim erratically, making it difficult for the fish to feed and avoid predators,” explained the U.S. Fish and Wildlife Service in a press release.

Once entering a water body, the disease persists through spores that can live for up to 30 years, even in dried-up streambeds.

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