Parasite is turning up in new places

spores of the whirling disease parasite were first detected in Wyoming during 1988. The spores were found in trout collected from private farm ponds and nearby streams and lakes in the Laramie and North Platte river drainages.

Since then, the parasite has been found in trout from the Salt River and Green River (including the lower New Fork) drainages in western Wyoming and the South Fork of the Shoshone River drainage in northwest Wyoming.

Recently, a brook trout and a brown trout tested positive for the parasite in Webster Creek, the Idaho creek which feeds water to brood fish ponds at the Wyoming Game and Fish Department's Auburn Hatchery in eastern Idaho.

The parasite was also been found last fall in Yellowstone National Park. They were found in Yellowstone cutthroat trout on the east side of Yellowstone Lake near the mouth of Clear Creek. Fish with clinical signs of whirling disease, including black tail, whirling behavior and deformities of the head and body, have been documented for rainbow trout in the Salt River and in Cedar Creek in the North Platte river drainage. No other fish with clinical signs of the disease have been found, and fisheries workers have not detected any depressed or missing year-classes of fish in any Wyoming waters.

Wyoming fisheries workers and scientists are monitoring the state's waters for the presence of whirling disease, says G&F fish pathologist Dave Money.

"As far as I'm concerned, it's not a panic situation," Money says. "People have been dealing with this bug since the 1890s in Europe, and they still have rainbow trout over there." Like other states dealing with whirling disease, Wyoming is studying the parasite. Much of Wyoming's research is happening at the University of Wyoming. Jim Rose, a psychology, zoology and physiology professor at the university, is studying the disease's effects on the central nervous system. Wayne Hubert, assistant leader of the Wyoming Cooperative Fish and Wildlife Research Unit and zoology professor, and his graduate students are looking at the effects of the parasite on Wyoming's wild fish populations in the Salt River. And, G&F forensic analysist Dee Dee Hawk is investigating new highly sensitive DNA methods to help improve the capabilities of finding the organism. Rose's research is supported by the National Science Foundation. G&F funding is going toward the research, as is some from The National Partnership on Wild and Native Coldwater Fisheries and the Whirling Disease Foundation in Bozeman, Montana.

The Whirling Disease Foundation, Inc., was established in 1995. Its mission is to raise funds needed for whirling disease research. The foundation supports field and laboratory research on a national scale, and selects research proposals for funding. It provides a forum for research coordination and information exchange.

"(Whirling disease's parasite) is a very unique organism in that it shares many of the characteristics of both the plant and animal worlds," Money says. "What we do know is that we've seen very few fish with any obvious signs of whirling disease (in Wyoming)."

Money and some researchers believe the best approach to dealing with whirling disease is to try to understand why the parasite is being found in the wild, and "to find out why it's doing what it's doing."

"I think the secret lies with maintaining our water quality, and that's been strongly suggested by studies on whirling disease," he says. "That's been strongly suggested about other diseases, too. When water quality declines, things seem to occur with diseases."

"When you have a polluted environment, polluted in an ecological sense with a lot of disturbance - any type of man-made, man-caused, animal-caused disturbance - it's going to disturb the balance," Money says.

"We need to constantly focus on the environment," Money says. "The fish are a reflector, just like a mirror, of what's going on in our environment. That's important, not only from a fisheries standpoint, from the wildlife communities and from our own personal health point of view. We need to know what's going on with water quality. Those studies are essential."

The presence of the whirling disease parasite in the Green River drainage has caused concern for two G&F hatcheries, Boulder Rearing Station and Daniel Hatchery.

In 1998, the whirling disease parasite was detected in Forty Rod Creek, a tributary of the Green River. The significance of Forty Rod Creek is that its path leads it near G&F's Daniel Hatchery. As a result, G&F plans to spend about $600,000 this year to protect the facility from whirling disease and to renovate outdated facilities. G&F will be compensated for 75 percent of the work from federal Sport Fish Restoration Program funding. "Beyond protecting it against whirling disease, the new building should enhance the quality of brood stock and overall facility production," says G&F hatchery coordinator Steve Sharon. "We've had up to 40 percent predation on our brood stocks there, both sensitive brood stocks of the Colorado River and Bear River cutthroat trout."

When Daniel's work is complete, the facility will be totally enclosed under a new 120- by 220-foot steel building. "When you cover a brood stock, a lot of the problems with post-spawning fungus are almost eliminated. This situation will give those brood stocks the opportunity to be a lot more productive," Sharon says.

Sharon says G&F had two choices at the Daniel Hatchery. "We could either close the facility or protect the facility," he says. "We're taking a proactive stance to prevent it from coming into the facility."

"We have clean facilities," Sharon continues. "We are being proactive and removing the chance of influence of whirling disease where we have had to make a choice."

"If a (G&F) facility becomes positive, those fish will not be stocked. We will not influence or increase the level of whirling disease in the wild," Sharon says. "We had only one choice at Daniel. If we didn't protect the facility, we would always run the risk of becoming positive (for whirling disease)."

With growing concerns in the Green River drainage, G&F also plans to spend about $200,000 this year to close the open water system at the Boulder Rearing Station, and another $120,000 to build a disinfection and storage facility near Boulder for G&F's fish spawning crew. Again, G&F will be reimbursed for seventy-five percent of the work from federal aid.

"Closing the water system will remove us from possible exposure," Sharon says.

G&F's spawning operation currently shares a 40- by 80-foot workshop building with department workers at the Boulder facility. Most of the spawning crew's equipment has been stored near the hatchery, too.

"It really hasn't been a good way of doing business," Sharon says. "We need to isolate our spawning operations away from the hatchery."

On the same property, G&F plans to construct another facility to house the disinfection and storage facility. The 50- by 60-foot building will have a 20- by 60-foot indoor bay where spawning equipment can be disinfected. The bay will have a sump, and water will treated with chlorine before sent to an evaporation pond.

"If there is any disease or any kind of parasite or bacteria, it's going to get nailed by chlorine and it will also be taken to an evaporation pond," Sharon says.

The facility "will also give our other crews - construction and fisheries a site to disinfect their equipment," Sharon adds. "This facility will eliminate any possible interaction between the hatchery and our spawning equipment."

G&F Fisheries Chief Mike Stone says one of the most troubling aspects is how the whirling disease parasite can show up in waters where the mode of transmission cannot be determined. Ò"Based on what we have seen in recent years, we can expect additional locations to become infected," Stone says. "Whirling disease has already had an adverse effect on our operations. Additional time and expense have been incurred to insure that we don't contribute to the problem."

G&F has established protocols for dealing with the whirling disease parasite in its fisheries operations to "thwart further movement of Myxobolus cerebralis spores among drainages." These protocols include fish sampling guidelines to monitor for the parasite, fish culture sidebars to keep the parasite from being moved into drainages during stocking, and the use of a strong public relations campaign to keep anglers involved in preventing the spread of the parasite. Sharon believes the whirling disease issue has a strong political slant. He says most people believe that the disease is a problem with hatcheries and fish culture. "In Wyoming, we're not the source of the problem. We're part of the solution. Wyoming hasn't seen any dramatic changes in wild populations."

"It's kind of like dancing in a mine field," Sharon says. "We don't know what's going to happen. It's all speculation. The best thing we can do is be proactive.

"We are being proactive to prevent the wild from infecting a hatchery," he says.

If a Wyoming hatchery does become infected with the whirling disease parasite, action will be taken. "It will be quick and swift," Sharon adds. "It's not going to take a lot of thought. All positive lots (of fish) and all exposed lots will be destroyed."

Money, however, believes wildlife agencies should be wary of killing wild populations of fish to control disease. "What's going to happen down the road if our Colorado River cutthroats get whirling disease?" Money wonders. "Are we going to kill the last of that remnant population to get rid of this parasite? We are going to have to consider that down the road. It's going to happen. Methods are getting more sensitive to detect diseases and pathogens now, and pretty soon we're going to start finding out that more of these fish have diseases. We're going to find that we are not living in a sterile environment."

Sharon wonders, too, about the disease and why it continues to turn up in new places. "You want to know the ridiculous part? We have nine or 10 sites that we annually inspect for wild brood stock sources, and we've never seen whirling disease there," he says. "Maybe it's the environment. The spread of this parasite is happening due to a natural situation," he says. Stone believes Wyoming will continue to have viable trout fisheries. "We may see changes in certain drainages, and some types of fisheries may be different from what we have known," he says. "Others will likely remain unaffected."

"From a fisheries management perspective, the effects of whirling disease are still impossible to predict with certainty," Stone continues. "The base of knowledge about whirling disease is increasing, but plenty of unanswered questions remain. The parasite has been present in the United States for decades, and effects have been highly variable. Little or no effect has been documented in certain waters and states, while it has been devastating in others. The long-term effects in those waters where it has been devastating are unknown."

Plenty of unanswered questions remain. The general consensus among scientists involved in research is that whirling disease and its parasite can be controlled in hatcheries. Early results from Colorado's massive fight offer hope for hatcheries which test positive for the disease.

In the wild, though, it's another story. Once a wild area is infected, it's generally believed that the disease cannot be totally eliminated from the environment. Some states have seen encouraging signs that levels of infection can drop over time.

"There currently is no practical means of controlling whirling disease in the wild. There is growing concern that some potential approaches for control in the wild may lead to inadvertant environmental disruption, so caution is needed before jumping to apply an unproven cure" Stone says.

"One of the big challenges for fisheries in the future results from a modern, mobile global society. Exotic organisms from parasites to mollusks, fish species and vegetation are finding their way to new parts of the world with increasing frequency. Whirling disease is but one of these organisms which threaten aquatic systems worldwide," Stone adds.

Intense research on whirling disease continues and will happen well into the future. It's safe to say that whirling disease and its parasite are receiving their share of study and research money.

One thing's for sure. Researchers, fisheries managers, scientists and fishermen have a long-standing love affair with trout, salmon and grayling. The leaper of the group, the rainbow trout, won't likely disappear. But everyone in Wyoming, including fishermen, must learn to live with the threat posed by whirling disease and its parasite. They're here.