Saving the last pristine habitat of Yellowstone Cutthroat
By Tyler Allen Explorebigsky.com Staff Writer
Congress created Yellowstone National Park in 1872, writing the first chapter in one of our nation’s proudest narratives. Widely considered the world’s first national park, Yellowstone began a legacy of conservation that continues to be written to this day.
Biologists in the park are currently drafting another part of the story: preserving the native Yellowstone cutthroat trout and the integrity of the Greater Yellowstone Ecosystem.
It’s unclear when or how the non-native lake trout made it to Yellowstone Lake.
The U.S. Fish Commission in the 1890s intentionally brought them to two other lakes in the park, Lewis and Shoshone lakes, as a sport-fishing resource. Whether they were intentionally released into Yellowstone Lake from that population will never be known, but one thing is clear: since the first lake trout was documented there in 1994, the historic cutthroat population of 4 million has seen significant decline, and is now at about 400,000.
The larger, longer-lived lake trout evolved as a predator in the Great Lakes of the Midwest; in Yellowstone Lake, they feed on cutthroats at a rate of 40-50 per year, according to Todd Koel, Supervisory Fisheries Biologist for the park.
Yellowstone cutthroat trout are a keystone species in the park, with more than 40 species depending on them as a food source. Their decline has implications for the entire Greater Yellowstone Ecosystem.
Because the cutthroat live in the upper 40 feet of the lake, they’re a food source for birds like white pelicans, bald eagle and osprey. Otters, grizzly bears and bald eagles feed on the cutthroat during their spring spawning run in the Yellowstone River and tributaries.
The lake trout, however, are mostly unavailable to these species, because they inhabit deeper water and spawn in the lake. Starting with their discovery in 1994, park biologists have been developing a program to suppress, and if possible, eradicate the lake trout.
“Fish are not necessarily a charismatic species . . . to anglers they are, but not the general public,” said park superintendent Dan Wenk. “[However] this is the most important restoration work in the park.”
Using live trap nets and gill nets, the National Park Service, with help from commercial fishing boats, caught and killed more than 300,000 lake trout in 2012. And the cutthroats are responding.
“We’re seeing way more cutthroats this year,” NPS Fisheries Biologist Patricia Bigelow said in late September.
The cutthroats they’re catching – mostly released unharmed from trap nets or gill nets –were typically larger in 2012 than 2011, according to size distribution data collected.
“It’s a very simple system,” Bigelow said. “If we can fish them out of the Great Lakes, fish [other species] out of the oceans, we can do it here.”
That’s good news for the more charismatic species that depend on the cutthroats, and ultimately, for the millions of visitors who come to see them.
A history of conservation
The Act of Dedication, signed by Ulysses S. Grant on March 1, 1872, explicitly created Yellowstone National Park “for the benefit and enjoyment of the people.”
Those famous words were taken from a letter by Ferdinand V. Hayden, an American geologist and leader of the Hayden expeditions in 1860 and 1871. His team of explorers, photographers and painters documented the landscape and geologic features in the Yellowstone region. This imagery, including striking large-format photographs by William Henry Jackson and paintings by Thomas Moran, helped convince Congress to withdraw the land from public auction and entrust it to subsequent generations of Americans.
A “supervolcano” created the landscape in and around the park. Known as the Yellowstone Caldera, it also created the largest concentration of geothermal features in the world. The national park is also the cornerstone of the Greater Yellowstone Ecosystem, a 20 million-acre expanse of land that includes Grand Teton National Park, as well as adjoining National Forests and wilderness areas.
Unique to the natural world, this corner of the planet evokes emotion from both visitors and residents of the ecosystem– which may be the only reason it still exists intact.
Many of the 4 million annual visitors to Yellowstone come to view some of the last remaining grizzly bears, bison and wolves in the contiguous United States. Others travel to the park for the cutthroats themselves.
Al Johnson grew up in Gallatin Gateway, Montana, and spent weekends with his family, fishing Yellowstone Lake and the river below it. A retired bank executive now living in nearby Big Sky, he remembers the family routine “of stopping on Fishing Bridge and watching the cutthroats spawn in June.”
Johnson learned of the declining cutthroat population 15 years ago and has experienced it first-hand since. Prior to moving back to Montana from the Midwest, he made yearly visits to the park. He catches fewer cutthroats in the Yellowstone River each year, he says.
“I would like to bring my grandkids to the park to have the same experience I had as a kid.”
Removing the invader
When the ice in Yellowstone Lake melts in late May or early June, the park begins its lake trout fishing season in earnest. The work continues until the autumn snows and cold temperatures shut them down.
Park biologists catch, tag and release select lake trout, and then use radio telemetry to target populations.
The park service operates a gill net boat called Freedom; Hickey Brothers Research, based in Sturgeon Bay, Wisconsin, operates two others and plans to bring a third for summer 2013. The Northwester manages the gill nets, while the Kokanee sets and pulls the trap nets.
Like a giant funnel, the trap has large netting wings extending from its mouth. The smaller cutthroats and juvenile lake trout pass through the nets, while the larger ones are blocked and must swim the length of the net, attempting to get around it. Eventually, they find an opening they swim into but can’t escape.
A few days later, skilled fishermen use winches to pull the traps. Nearly all the fish they pull in are alive – the cutthroat are released back into the lake, and the lake trout have their air sacs cut open, so they’ll sink when thrown overboard.
The gill net locations are set in shallower water, where they’re laid in a precise serpentine course to confuse the fish and prevent them from swimming around the nets. When a fish swims directly into the nets, its gills are caught, and it cannot wriggle free.
A model of success?
Lake trout were intentionally introduced to Lake Pend Oreille in northern Idaho in 1925, a result of the same fisheries management that brought lake trout to Yellowstone.
“It was a time in our fisheries management history when folks didn’t understand the consequences [of introducing exotic species],” said Andy Dux, Principal Fisheries Research Biologist with the Idaho Department of Fish and Game, which has run a similar lake trout suppression program there since 2006.
Their numbers in Lake Pend Oreille remained low until the late 1990s, at which point they began to out-compete the lake’s population of kokanee trout, also non-native. The growth was a delayed response to the 1960s introduction of Mysis shrimp, brought to the lake by biologists in hopes of benefitting the kokanee, a popular sport fish and a food source for the native bull trout.
Bull trout are listed federally as a Threatened species throughout their range in the Northwest, but the efforts in Lake Pend Oreille are encouraging.
“Lake trout suppression has been extremely effective, thus far,” Dux said. Adult lake trout have declined by more than 80 percent since the program was initiated, and the kokanee have responded favorably, he said, its population at its highest level since the fishery was closed to anglers in 2000.
These results of the Lake Pend Oreille trapping operation would seem to offer more than a glimmer of hope that Yellowstone Lake and other fisheries in the region can recover with intensive efforts.
Biologists working on Pend Oreille have a couple more arrows in their quiver.
The Angler Incentive Program pays fisherman $15 for every lake trout they remove. In the seven years since suppression began, this has accounted for nearly half of the 143,000 lake trout killed.
They also have funding. Power companies that operate dams above and below the lake are obligated to fund mitigation for the negative impacts on the ecosystem caused by hydroelectric infrastructure. That amounts to about $1 million a year. With Lake Pend Oreille once a world class fishery and Idaho’s angling crown jewel, state fisheries managers are willing to spend the money it takes to regain that status.
Early signs of success
The entire Yellowstone Lake watershed is unfettered by human consumption of hydroelectric power. The 692-mile Yellowstone River, as well, is undammed. The wild nature of the system is part of the allure for the millions who marvel at the lake’s beauty each year, but it means the hydrological system has had limited resources.
Yellowstone Park Foundation is the primary fundraising partner for Yellowstone National Park and has donated to the park’s native fish program for more than 10 years. In March 2012, YPF cemented its commitment to Yellowstone cutthroat recovery with a donation of $1 million, and a fundraising goal of another $1 million annually through 2016, if necessary.
Already, it’s making a difference.
“This year was the first time in more than a decade we’ve seen a significant decline in juvenile lake trout,” said park fish biologist Todd Koel. “There was an increase in the total number of cutthroat being caught.”
The additional funding means more nets in the water, more man hours and next year, another boat on the lake.
“Lake trout probably won’t be completely eradicated [in Yellowstone Lake],” said Pat Byorth, Staff Attorney for Montana Water Project. Biologists are learning creative ways to help cutthroat survive even in the presence of these predators, he said. “It’s more than just putting down lake trout. The product of these efforts has greater implications.”
Yellowstone Park Foundation
Mission: To protect, preserve and enhance Yellowstone by funding projects beyond the financial capacity of the National Park Service.
Founded in 1996 by a group of dedicated citizens, the nonprofit Yellowstone Park Foundation has since raised more than $60 million for the park.
In October 2012, a museum-quality exhibit called Destination Yellowstone opened in the Bozeman Yellowstone International Airport. YPF, partnering with the Yellowstone Association, the NPS and the airport, installed a mural depicting iconic Yellowstone wildlife, a web-based, LCD park map, a live webcam of Old Faithful, and a 55-inch interactive touch screen with Yellowstone facts, photos and information on YPF.
Approximately 850,000 passengers came through the airport in 2012 – up 50,000 from the previous year, according to Airport Director Brian Sprenger. Visitors to Yellowstone make up a significant portion of those travelers.
The new exhibit offers them “important information before they get there,” says park superintendent Dan Wenk. “When they return and want to get involved, with the YPF exhibits, they can find out how.”
More at ypf.org.