There’s trouble in Paradise.
Literally.
Early results from studies of whirling disease infection in populations of Yellowstone cutthroat trout indicate an extreme level of susceptibility that spells trouble for one of the nation’s most treasured trout locations.
Nowhere is the concern greater than in Paradise Valley, the spectacularly scenic and fish-fertile reach of the Yellowstone River where it flows from Yellowstone National Park downstream to Livingston, Mont.
Early research reveals that the disease fatal to young trout has made its way into two-thirds of the tributaries that provide the bulk of reproduction for this internationally famous fishing area.
For Colorado anglers who love fishing for Yellowstone cutthroat, both in and outside the park, this news is not good. Worse, lab testing has shown the Yellowstone cutthroat to be six to seven times more susceptible to the malady than rainbow trout.
“What concerns me is the susceptibility level,” said Dick Vincent, whirling disease research coordinator with the Montana Department of Fish, Wildlife & Parks. “That’s scary. If they’re going to be bothered by such a small exposure, we’re in a lot of trouble.”
The worry began some time ago farther upstream in Yellowstone Lake, where this celebrated native trout suffers a double-edged attack. Much has been discussed about an explosion of lake trout chewing away at what once was the most remarkable fishery in the region.
Yellowstone National Park officials have removed more than 270,000 lake trout over the past 13 years, 73,000 in 2007 alone, in an effort that has cost $3 million. More recently, the National Park Service has formed a partnership with Trout Unlimited and the U.S. Geological Survey to develop an alternative method to eliminate the illegally introduced lake trout.
At the same time, whirling disease has taken a less-publicized, but perhaps more profound, toll.
Dave Kumlien, executive director of the Bozeman, Mont.-based Whirling Disease Foundation, reports that a major lake tributary, Pelican Creek, no longer produces young trout. Similar problems exist in Clear Creek and other tributaries.
“This thing about infection in the Yellowstone River in Montana hasn’t really been in the media, but it will cause a great deal of concern,” Kumlien said. “This river has a great constituency — anglers, guides, shops, landowners.”
By official estimate, the Yellowstone cutthroat now occupies less than 43 percent of its historic range, in large part because of introduction of competing non-native trout and environmental degradation. Like all native trout, including those in Colorado, it is highly impacted by exotics such as rainbow and brook trout.
Now comes this latest threat posed by whirling disease, far greater to cutthroat that cannot be hybridized with more resistant strains.
“There’s no way to get that genie back into the jar,” said Vincent, who also lamented a general lack of information about the Yellowstone subspecies.
Charlie Meyers: 303-954-1609 or cmeyers@denverpost.com
