With illegally introduced lake trout swarming throughout Yellowstone Lake, approximately 90 percent of the native species, Yellowstone cutthroat trout, have been eliminated since the mid 1990s when the lake trout took hold.
This has led biologists and wildlife activists to unite to save the endangered species through a variety of plans, partly since fishing for the cutthroats in Yellowstone Lake and its tributaries has been a popular tourist activity. Also, the cutthroats are considered a keystone species in the Yellowstone area that effectively dictate how other species live. For instance, since cutthroats spawn in streams, they are a prime catch for backcountry bears, making the animal highest on Yellowstone’s food chain less likely to become problematic for tourists. Lake trout, by contrast, never leave the lake.
When efforts first began, things looked pretty hopeless, but experts have more recently identified a number of ways to harvest lake trout without hurting the cutthroats simultaneously. And the effort appears to be working. In 2011, about 220,000 lake trout were removed from the voluminous Yellowstone Lake, a huge improvement even from the previous year, when 150,000 fish were harvested. Meanwhile, 2011 was the first year in which the cutthroats showed an increase in population in more than a decade. Under current fishing regulations, fishermen on Yellowstone Lake are required to kill or keep lake trout while being required to release every cutthroat caught.
The newest attack on the lake trout endangering Yellowstone cutthroats involves technology more heavily than before. While previous efforts involved netting as many fish as possible among other angler angles, the new efforts attack problem fish before or shortly after they are born by identifying breeding grounds. Since carbon dioxide is toxic to newly born lake trout, one environmentally sound option would involve dropping weighted dry ice into spawning beds.
But the largest problem facing biologists is finding the spawning beds. Luckily, cutthroats spawn in streams and tributaries while lake trout spawn in the lake itself, meaning experts can attack the spawning beds without worrying too much about detrimental effects to cutthroats. But to find the locations heaviest with lake trout eggs, National Park Service biologists have begun to implant tracking chips that will cause so-called “Judas fish” to betray their species by leading biologists to their spawning grounds.
The program needs more funding to be most effective. Though the National Park Service has employed gill netting to the tune of $1 million annually, Trout Unlimited and the Yellowstone Park Foundation hope to raise $85,000 by May to install the transmitters and receivers that track the lake trout for a fuller distribution in the lake. According to the Trout Unlimited website, they are still $23,000 shy of the goal. Meanwhile, the Yellowstone Park Foundation made a $1 million donation to the program in February. The donation was matched by federal funding.