Cutthroat trout were the dominant fish in Yellowstone Lake for most of the history Yellowstone National Park However, in the 1980's lake trout were introduced.
The lake trout are bigger, and more aggressive than the native cutthroat and that has hurt the native fish population. Researchers now know the loss of cutthroat also has an impact on the creatures on the land that feed on them. That connection means that Yellowstone National Park officials now have to try to remove the lake trout.
"As managers there's really no way that we can totally eradicate that invasive species," explained YNP Native Fish Conservation Program leader Todd Koel. "They are pretty much here to stay, all we can do is manage the best that we can their numbers in our case for lake trout to suppress them using an aggressive gill netting program and by suppressing the lake trout we're allowing the cutthroat trout then to rebound and become an ecologically important component of that system again.
The efforts to suppress the lake trout in Yellowstone Lake are being hampered by the weather. Suppression efforts can only happen about six months out of the year since the lake is frozen for the rest of the year -- something that gives the lake trout an advantage.