Colorado Study Reveals
Trout Populations
Devastated By Disease
DENVER - A disease that attacks the bone structure of young fish has wiped out 90 percent of Colorado's wild rainbow trout in six of the state's best trout streams, a state study shows.
The study by the Colorado Division of Wildlife also found that Whirling disease has reached 12 of the state's 15 trout hatcheries, threatening the state's $420 million-a-year fishing industry.
"It's like getting pounded by a sledgehammer. The disease is having a devastating effect," said Barry Nehring, state fishery biologist and author of the five-year study. "These were the best of the best rivers in Colorado."
Whirling disease has killed millions of fish in such rivers as the Colorado, South Platte, Gunnison, Rio Grande, Cache la Poudre and Dolores.
The disease, which poses no threat to human health, is caused by a microscopic spore that attacks the bone structure of baby fish. While it may not kill the fish, the resulting whirling behavior makes the fish unable to feed normally and more vulnerable to predators.
State officials say Colorado's fish became infected after a private hatchery unwittingly accepted a shipment of diseased fish from Idaho. The disease affects trout streams in 22 states.
Eradicating the disease from state fish hatcheries and making improvements to prevent another outbreak are expected to cost at least $13 million. The hope is to have all hatcheries disinfected - and producing 3.5 million fish a year - by 2002.