Biologists Remove Large Number of Lake Trout From Yellowstone Lake

The effort to remove non-native lake trout from Yellowstone Lake seems to once again be paying dividends.

Between May and October, National Park Service workers removed about 315,000 lake trout, according to Todd Koel, a fisheries biologist and leader of Yellowstone National Park’s native fish conservation program.

“That’s more than we’ve ever caught,” Koel told the Casper Star Tribune. “It’s because we put out even more effort than we have ever before to catch them. … And also there’s a lot lake trout out there.”

Indeed, removing non-native lake trout from Yellowstone Lake has been ongoing since the fish were discovered in 1994. Their arrival coincided with a decline in cutthroat trout, who, along with arctic grayling, have become the subject of intense conservation efforts. Although officials have sought to remove lake trout from the Park since the mid-1990s, they ramped up efforts in 2012 and started netting and electroshocking, along with other methods. The conservation program costs around $2 million, with funding provided by the federal government and private donors. From the Tribune:

Koel said about 1.2 million lake trout have been killed in just the last four years.

In 2012 and 2013, about 300,000 lake trout were removed each year and another 277,000 in 2014.

“Each year, we’re putting more and more effort out there and each year we’ve been killing a lot of fish,” Koel said. “We’re still waiting for that crash in our catch. We haven’t seen that yet, but the predictions are there that’s going to happen. So we’ll keep this up until it does.”

In the meantime, the Yellowstone cutthroat population is rebounding, which is expected to have an impact on native bird and bear species. Experts have perceived lake trout removal efforts as overall successful, so far. Fisheries biologists in the Park expect to continue working on removing lake trout and restoring native fish into the near future.