CODY — Biologists are planning to cast a wider net — literally — in their efforts to remove non-native fish from some waters in Yellowstone National Park. They propose hiring large, commercial operators using big boats with giant nets as part of a plan to remove lake trout and allow for a rebound in native Yellowstone cutthroat trout.
Use of chemical poisons in some streams is also under consideration.
For years, park managers have fought a losing battle against a growing lake trout population in Yellowstone Lake. They have used miles of gill nets to catch the larger lake trout, which gobble up young cutthroat.
Because cutthroat spawn and swim in shallow waters, including tributaries around the lake, they are more available as food for grizzly bears, bald eagles and other animals than are lake trout, which spend most of their time in deeper waters.
Lake trout are only one of several non-native fish introduced into the park’s many lakes, rivers and streams over the past century or more. But their increasing numbers in Yellowstone Lake pose the biggest threat to cutthroat, said Dave Sweet, a director of the East Yellowstone Chapter of Trout Unlimited.
Sweet said he plans to attend a public meeting in Cody on Tuesday to learn more about the park’s fish management plans, but he is in favor of proposed increases in lake trout netting, including the use of commercial gill netters.
“I think it’s long overdue,” Sweet said. “I think the Park Service should have been taking a much more aggressive posture for a long time in trying to reduce lake trout in Yellowstone Lake and trying to preserve the cutthroat.”
Sweet said he wanted to learn more about the possible use of chemical poisons in streams in the northwest section of the park, where non-native fish may be killed to make way for restocking of westslope cutthroat trout. Similar efforts may be used to help restore Arctic grayling in other waters in Yellowstone.
“I think that’s a good idea, as long as they don’t get too carried away” with the use of chemical treatments, he said.
Biologists have no plans to target rainbow trout, brown trout and other non-native fish in the Firehole and Madison rivers.
“I certainly support bringing back the Yellowstone cutthroat,” said fishing guide Tim Wade, who also owns a Cody fly shop.
But determining how much chemical poison to use, and where, can be a tricky calculation, he said.
Recent efforts to rid other local waters outside the park of unwanted fish have shown that it can take years before those fisheries can fully support anglers again, he said.
“What works in a textbook and a controlled environment like a biology lab isn’t always the same in nature, where things are very dynamic,” Wade said.
Gateway communities rely on money spent by fishermen, so in the short term, the native fish restoration plan could mean “we are going to see a hit to our pocketbook, so I hope they consider the economic issues, too,” he said.
Comments on the park’s fish plan will be accepted through April 30 and can be submitted at parkplanning.nps.gov/yell.