The signal event in the 14 years that the Whirling Disease Symposium has been held came with a whimper rather than a bang.
In 2002, before a packed conference at a Denver hotel, a small man with a pronounced accent described the discovery of a rainbow trout strain resistant to the malady fatal to North American trout.
Few cheered. In fact, many scientists in attendance rushed the podium to attack Mansour El-Matbouli as if he were peddling the aquatic equivalent of biological snake oil.
One who did embrace the finding was Eric Hughes, then head of the Colorado Division of Wildlife hatchery system, soon to be the state aquatic chief. Hughes was mired in a staggering eight-figure cleanup of Colorado’s entire hatchery network. Thing was, even when the costly project had been completed, when nearly all units were free of whirling disease, the result would do nothing to restore wild, stream-bred rainbow trout.
Years later, the initiative Hughes launched from the inspiration of that earlier conference seems likely to revolutionize the way fish managers confront the almost universal threat of whirling disease.
More precisely, Colorado’s extensive cross-breeding experiment has produced the first WD-resistant rainbow progeny born in the wild. Trials conducted last fall in the lower Gunnison River and a private pond near the Frying Pan River produced surviving fry genetically linked to hybrid trout stocked two years earlier.
“The gene is clearly there,” said Barry Nehring, thrilled at this breakthrough following 15 years as the project leader of DOW’s thrust to recover from a long, dark tunnel of rainbow deprivation. Finally, the Colorado agency has a rainbow trout that can survive and reproduce naturally in the wild.
Nehring said DOW soon will have two to three million eggs in its hatchery system from resistant fish to plant at various places in the wild. In the not-so-distant future, surely less than a decade, rainbow trout again can thrive in Colorado streams.
When the Whirling Disease Symposium returns to Denver on Monday and Tuesday for its final formal gathering, Nehring will give three separate talks on his findings. George Schisler, the DOW researcher who directed the successful hybrid tests that produced these wild offspring, will deliver another.
Presumably, the reception will be considerably different than El-Matbouli received when he presented that landmark finding here in 2002. A native of Egypt performing research at the University of Munich, he discovered a WD-resistant rainbow strain in a Bavarian hatchery. This so-called Hofer strain subsequently was imported to the U.S. and now forms the centerpiece in the cross-breeding process that produced this recent Colorado success.
The WD-resistant fry recovered from the lower Gunnison, a place ravaged by whirling disease, demonstrated better health than expected.
“They were among the biggest rainbow fry we’ve ever discovered, with no clinical signs of the disease,” Nehring said.
The biologist found similar resistance in fry from the Frying Pan pond.
The two-day symposium at the downtown Grand Hyatt will, alas, be the final such formal event for a foundation that last autumn was merged with National Trout Unlimited. Instead, meetings will be held in conjunction with other gatherings of North American fisheries officials.
Dave Kumlien, executive director of the Bozeman, Mont.-based foundation, emphasized that the rainbow revival in no way means that the threat of whirling disease is diminished.
Kumlien pointed to an alarming spread of the disease in Yellowstone cutthroat trout habitat and the peril to other native trout species — a worry that Nehring also holds for DOW’s effort to recover three cutthroat subspecies at many locations in the Colorado high country.
“The threat is as severe as it always has been,” Kumlien declared of a cutthroat condition that cannot be cured by hybridization.
Meanwhile, some 50 scientists will gather near the site where the winning rainbow strategy was born. El-Matbouli will be among them to hear these latest developments in the quiet transformation he launched six years ago.
Those in attendance all should shake his hand. Some also should apologize.
Charlie Meyers: 303-954-1609 or cmeyers@denverpost.com
