For more than a decade, fisheries biologists at Yellowstone National Park have been fighting what seems to be a losing battle to save Yellowstone Lake's vanishing native cutthroat trout. But over the last couple of years, crews have finally begun making some headway in the war against the non-native predators that have been driving the lake's native trout to the brink.

And help may be on the way.

The East Yellowstone Chapter of Trout Unlimited in Cody is spearheading an effort with Yellowstone National Park and the U.S. Geological Survey to raise $169,000 to fund a research project that could help save Yellowstone Lake's native cutthroat trout. The four-year research project would be conducted by scientists from Montana State University and the USGS who would try to find ways to eradicate unwanted lake trout by targeting their eggs and spawning beds with a variety of lethal methods, including electroshocking, ultrasound, microwaves, biodegradable polymers and fish-killing toxicants.

Every summer for 14 years at a cost of more than $3 million, the Park Service has tried to control Yellowstone Lake's unwanted non-native lake trout populations by catching adult lakers with gillnets. Crews sometimes haul in more than 10,000 lake trout in a single day from the 136-square-mile lake. Still, the lake trout keep multiplying -- and preying on the native trout.

"It's like mopping up the water that's leaking through the dam," said Dave Sweet, fundraising chairman for the Cody chapter of Trout Unlimited.

Lake trout can live longer than 20 years and are voracious predators that grow to enormous sizes.

"No one knows how the lake trout got in there. There's lots of speculation, lots of rumors and theories, but really it doesn't matter. They're there. The population of lake trout has mushroomed. It's gone through the roof," Sweet said.

Not long ago, the streams that feed Yellowstone Lake were teeming with fish in the springtime when countless native Yellowstone cutthroat trout surged upstream from the lake to spawn. Grizzly bears, black bears, osprey and otters feasted on the smorgasbord of spawning fish. Fly anglers who made the hike into the remote backcountry just outside Yellowstone National Park enjoyed fantastic fishing, often catching and releasing dozens upon dozens of cutthroat trout each day.

That's how it was up until the early 1990s when Yellowstone Lake held an estimated 9 million cutthroat trout -- the largest lake population of genetically pure Yellowstone cutthroat in the world. But also around that time, predatory, non-native lake trout were first discovered in the lake. Since then the lake trout have devoured the native cutthroat practically into oblivion. Only a fraction of the natives remain in the lake and hardly any migrate up the creeks anymore to spawn.

"We would see thousands and thousands of fish up there in the early 1990s," said Tim Wade, owner of North Fork Anglers fly shop in Cody, who used to lead backcountry fishing trips to the creeks that feed Yellowstone Lake. "It looked like Alaska. You'd see thousands and thousands of fish. I'd say there are less than dozens swimming up there now."

Before the lake trout invasion, visitors to Yellowstone could stand on the Fishing Bridge and peer down into Yellowstone Lake and see hundreds of cutthroat trout swimming in the blue water below. On the opening day of the park's fishing season, anglers would crowd the lake shore by the hundreds. But now that lake trout have all but taken over Yellowstone Lake, the deep-dwelling lakers are difficult to catch and are seldom seen. But they're in there, devouring what's left of the lake's once plentiful native trout.

"Now almost no one bothers going anymore because there are essentially no fish to be caught," Sweet said.

Park Service fish surveys over the last two years have shown that the lake's native cutthroat are beginning to bounce back -- a little -- sparking some hope that gillnetting the lake trout is helping. But gillnetting alone probably won't be enough to hold back the inevitable and the clock is ticking, said Yellowstone fisheries biologist Pat Bigelow.

"I think we really are at a critical point," Bigelow said. "It looks to me like the cutthroat population is starting to come around but at the same time it looks like the lake trout population is on the verge of an explosion. So it won't matter if the cutthroat are turning around because they will be overtaken by the lake trout."

Bigelow is hopeful the Montana State University and USGS research will lead to some new weapons the Park Service can use against Yellowstone Lake's non-natives -- before it's too late for the cutthroat.

"I think it would be very helpful. We have a very limited budget and staff. It's hard for us to stop something that's working (gillnetting) to try experimental methods. If they can figure out the best way to do it, we can fit it in," she said.

Recreational anglers who fish for lake trout, usually from boats equipped with downriggers, help only a little to reduce the number of adult lakers.

Gillnetting should continue, Sweet said, but park crews also need to go after the lake trout's eggs and spawning beds to really knock down their numbers. So far the Trout Unlimited chapter has raised about $10,000 in donations and secured a $10,000 grant from the USGS for the research project which would try to find ways to do just that.

Researchers will need at least $44,000 of the total $169,000 to get started on the project.

"We're trying every avenue to raise that money. We want to get started this summer. We don't want to wait another year," Sweet said.

Having native fish in Yellowstone Lake is "really important not just as a fishery, but it's very important to the whole ecosystem. The animals can't just switch and go to eating lake trout, which stay deep in the lake and don't go upstream to spawn. So the grizzly bears, the otters, the ospreys, those animals have had to find other food sources," he said.

Yellowstone cutthroat are a subspecies of cutthroat trout that are gone from much of their historic range, which encompasses large portions of Wyoming, Idaho and Montana, and small areas of Nevada and Utah. Where cutthroat have struggled to survive, habitat loss and non-native fish are usually the culprits.

Environmental groups have unsuccessfully petitioned the federal government to have Yellowstone cutthroat listed as a threatened or endangered species. If the natives vanished from Yellowstone Lake it could bring the subspecies one step closer to an Endangered Species Act listing, which could have widespread effects on recreational fishing and other activities in the region.

"It is certainly one of the Yellowstone cutthroat's last stands and its last major stand in genetically pure form," Sweet said. "It's not the last remnant population, I wouldn't want to say that, but it sure is the last major population that we just can't stand to lose."