Unbidden lake trout in Yellowstone Lake may find they can swim, but they cannot hide — if Trout Unlimited, federal and state entities and volunteers have their way.

Efforts have been under way for years to repress the lake trout population that preys on native Yellowstone cutthroat trout. Last week, Trout Unlimited organized a sort of fishing derby to catch and radio tag lake trout.

Lake trout were first noted in Yellowstone Lake in the mid 1990s. Soon after, the National Park Service began suppressing the population by gill-netting and then killing that specific fish.

However, methods that target lake trout embryos and/or larvae on spawning sites hold the greatest promise, according to the park’s Native Fish Conservation Program Yellowstone Fisheries & Aquatic Sciences 2012-2014.

In 2011, a telemetry study was initiated to locate spawning grounds and track lake trout. Since then, hydro-acoustic telemetry tags have been inserted into lake trout bellies to track them to spawning sites.

On a windy Thursday morning, three teams headed out on the lake in boats searching for lake trout. Each team kept its “surgery boat” in sight, since that’s where lake trout receive the surgically-implanted transmitters.

Joe and Kathy Reed, who farm near Corbett Bridge, were on the red team. Joe said they are not Trout Unlimited members, but they volunteered when asked by Trout Unlimited Yellowstone Lake Special Project manager Dave Sweet.

Some of the volunteer crews fished the entire week, while others invested two or three days. The Reeds have fished all week, Joe said.

Whitecaps resembling shifting snow drifts lurched across the lake while the boat bounced like a skipping stone over the waves.

Joe and Kathy took turns guiding their watercraft and trolling the fishing line. It took a steady, yet subtle, hand to maintain steerage, as the wind was bent on blowing the boat every whichaway.

The lake was smooth as glass Wednesday, Joe said. Their grandson caught three 22-inch cutthroat trout that day.

Not far from where Pelican Creek dumps into the lake, the Reeds kept a close eye on the two fish finders that spotted their quarry and reported the lake’s depth.

The lake was 18 feet deep at their location, but they wanted water 35-40 feet deep for the most effective trolling, Kathy said.

“Lakers” like to travel 5 feet above the bottom, Joe said.

Joe tried a “money clip,” a lure that works well on Buffalo Bill Reservoir lake trout where he likes to fish, he said.

Joe then tied a Mepps lure on another pole.

“Lots of fish here,” Kathy called while piloting the boat.

Indeed, fish icons slide across the screen like ducks in a shooting gallery. But the fish weren’t biting.

The boats bobbed in the swells like corks, making it grueling to maintain course, let alone fish. Finally, Sweet instructed the boats to head to Stevenson Island, where he hoped the lake would be more placid.

Lakeside surgery

The plan is to insert 180 hydro-acoustic telemetry tags into lake trout this week, but only 72 have been tagged, Sweet said.

They are angling for adult fish 20 inches or bigger, because they know the larger lakers are sexually mature, Sweet said. Ideally, they want big males because they will spawn at multiple breeding sites every fall, while females spawn every other year. 

“It’s like a 21-year-old kid looking for a date, hitting all the bars,” Sweet joked.

A 20.3-inch male was caught by another boat and transferred to the surgery boat.

The lake trout spent 2 minutes in a tub of lake water dosed with anesthesia. Then Jason Burckhardt, Wyoming Game and Fish Department fisheries biologist, made a three-fourths-inch slit on the side of the belly, slid the Tootsie Roll-sized transmitter in, then applied three sutures to close the incision. While Burckhardt operates, Jacob Scoville, Game and Fish fisheries technician, used a surgical hose to carefully squirt water into the laker’s gills and on its body to keep it breathing and wet.

Once surgery was complete, the lake trout was placed in a net immersed in the lake beside the boat, where it recovered from the drug before being released.

They may be pinning their hopes on the removal of all lake trout, but the guys were as gentle with the fish as a father handling his newborn child.

Once free of the net, the laker remained near the boat for a second as though suspended in water, then, with nimble flick of his tail, it’s gone.

“There he goes,” Sweet said. “He kicked away nicely.”

About one-half of the 1.7 million lake trout killed since 1994 were captured with gill nets, according to 2015 Yellowstone statistics.

Gill nets are effective, but unless fish are quickly untangled, they will die, Sweet said. Survival is much higher when they’re caught with fishing poles.

By triangulating movement, they can also determine density. More lakers in a given area is a sure indicator it’s a breeding ground, Sweet said. “We know right now about 12 spawning areas.”

“While 72 is a long way from our target of 180 tags, we should not be discouraged,” Sweet said in a memo to the volunteers. Robert Gresswell and Nicholas Heredia of the U.S. Geological Survey will decide how to insert the remaining tags.

Burckhardt guided the boat while three others cast for lake trout, but the lakers weren’t biting. Each angler landed at least one big cutthroat.

Sweet caught a nice, healthy cutthroat, reckoning it to weigh at least 4 pounds.

The hook was carefully removed from its mouth before releasing the trout. Like a rippling ribbon of gold seen through a prism of sun rays and translucent blue water, the cutthroat scooted.

“They’re such gorgeous fish,” Sweet said. “And to think there were once 4 million in the system.”

Lake trout fishing may not be that great today, but cutthroat fishing has been, suggesting that the cutthroat population is making a comeback, Sweet said.

For two days, Game and Fish employees from Jackson operated the surgery boat, which was borrowed from Grand Teton National Park, Burckhardt said. Then, Cody Game and Fish employees manned the boat for two days.

“We work a lot on these collaborative projects,” he said. 

The Park Service and Game and Fish are both committed to preserving native species such as cutthroats, Burckhardt said.

The lake trout project is a partnership between Game and Fish, U.S. Geological Survey, Park Service, Trout Unlimited and many others.

Game and Fish also is battling non-native fish. So, if the department can lend a hand, it is time well spent helping their neighbors in Yellowstone and learning more about lake trout repression strategies, Burckhardt said.

And, the Park Service has assisted Game and Fish and others with projects adjacent to its boundaries, Burckhardt said.

Rain, hail, wind and lightning hindered efforts, but the participants stuck it out, Sweet said.

“I have never before been involved with such a great group of volunteers who freely gave of their time, their resources and their energy to help save an imperiled species, the cutthroats of Yellowstone Lake,” he said.