Some great Yellowstone Park news in battle to kill off lake trout!

2012 was banner year for number of lake trout removed from Yellowstone Lake-

Yellowstone cutthroat trout numbers are finally seen to be increasing in what once was the world’s greatest Yellowstone cutthroat trout fishery — Yellowstone Lake.

A herculean effort over the last 3 years has resulted in the removal 300,000 of the invasive and ecologically damaging mackinaw (lake trout) that were illegally introduced into the lake in the early 1990s. Previously only 700,000 lake trout had been removed in the entire period 1994-2011.

A new Park news release tells of the increasingly successful program to kill the cutthroat-eating predators that now take so much of the Park’s biomass uselessly down into the lake’s sediments instead of upward into the dozens of Park animals that used to feed on the surface accessible cutthroat trout.

The lake trout elimination efforts have improved because of a better understanding where the mackinaw hang out and spawn, plus a  increased effort using traps and gillnets.  The news release states: “The National Park Service (NPS) increased the use of contracted netters to more thoroughly expand its reach in Yellowstone Lake again in 2012. From May to October the NPS and contract crews focused efforts in the West Thumb, Breeze Channel and Dot and Frank Island areas of the lake, where catches continue to be highest.”

While it is probably not possible to eliminate the scourge of Mackinaw entirely, this raises hope that threatened species such as grizzly bear that used to catch the cutts in about 60 of the lake’s tributary streams will again be using the lake in the near future.

The bigger and higher quality removal effort costs and the Park Service gives credit to a “strong partnership with the Yellowstone Park Foundation, Trout Unlimited, Greater Yellowstone Coalition, and the National Parks Conservation Association. ”







  1. jdubya Avatar

    This is indeed good news. But one of the major limiting forces at work, whirling disease, may still keep cutt numbers below where they should be.

    I have not heard anything on the WD front for a while regarding the selection of resistant Cutt’s in the lake. But with better survival from the lakers, maybe the cutt can now develop resistance the same way the rainbows in the Madison have.

  2. Ralph Maughan Avatar
    Ralph Maughan


    I haven’t heard about the status of whirling disease in the Park lately either. I know it got so bad that trout were eliminated from Pelican Creek and its tributaries. I don’t know if they have recovered at al1.

  3. SEAK Mossback Avatar
    SEAK Mossback

    That’s great news! Unfortunately, at this point it appears to be a forever commitment, but at least this provides substantial reason for hope that it will not be in vain — and hopefully made more effective in the future with increased knowledge and technology.

  4. Scott Brand Avatar
    Scott Brand

    This is a noble effort but I doubt there are any pure cutthroat in the lake. Most are hybrid cutthroat x rainbow or maybe even cutthroat x lake. We have done are best to move rainbows, lake and walleye to every possible place they could survive and now we are trying to get rid of them because they destroy the native fish. Example of act first, think later.

  5. Ralph Maughan Avatar
    Ralph Maughan

    Scott Brand,

    An interesting comment but entirely incorrect as it applies to Yellowstone Lake and its tributaries above the falls. They are pure Yellowstone cutthroat trout. See this pdf file, or do a search of your own. This URL also gives a great deal of graphic and pictorial information of the lake trout invasion and efforts to control it.

    Lake trout no not hybridize, except occasionally with brook trout, producing the sterile splake. There are no cutthroat x lake trout.

  6. Craig Avatar

    But there are Cutbows in all of those areas, I’ve caught many. Hopefully people keep them and don’t release. I’m all for and practice catch and release except in situations like this.

    1. Ralph Maughan Avatar
      Ralph Maughan


      Cutbows (brook trout x cutthroat, for those not familiar) do not occur in Yellowstone Lake either because there are no brook trout.

      1. elk275 Avatar

        A cutbow is a cross between a rainbow and Cutthroat. I do not think that a cutthroat and a brooktrout can cross. A cutthroat is spring spawner and a brooktrout is fall spawner. A cutthroat is a member of the salmon family and a brook trout is a member of the char family.

        1. Mark Gamblin (IDFG) Avatar
          Mark Gamblin (IDFG)

          The popular term “cutbow” refers to a cutthroat x rainbow hybrid. There are no cutthroat x rainbow hybrids in Yellowstone Lake, which still supports one of the most important non-hybridized Yellowstone cutthroat trout populations in the historical range of the sub-species.

          1. JB Avatar

            Off topic–

            Mark: Can you give us any details/updates on what has come out of the Wildlife Summit?

            1. elk275 Avatar

              You may have caught cutbows in the Yellowstone River below the falls, not in Yellowstone Lake or the river above the falls.

            2. Mark Gamblin (IDFG) Avatar
              Mark Gamblin (IDFG)

              JB, All –

              The Idaho Wildlife Summit (August 24, 25, 26) was attended by 500 participants in 7 cities and 3,000 internet participants on Saturday, making it the single largest wildlife resource public involvement event in the history of Idaho. The entire program was streamed on the internet and video recorded for future viewing and special productions. The IDFG web site has a page dedicated to the Summit:


              with segments on each Summit discussion, exercise and presentations by invited speakers. The Wildlife Summit report, a thorough compiliation/summary of stakeholder comments and contributions is also available on the Wildlife Summit web page. The Wildlife Summit was/is a landmark event for Idaho wildlife conservation and management. Comments during and after the Summit have been enthusiastically positive. Many suggestion/requests for regular Summit-like events to continue the dialog and partnership among Idahoans for strong and effective conservation of Idaho wildlife and wildlife traditions. We are now working with Summit participants and other Idaho wildlife stakeholders to stay engaged and build on the progress and momentum the Wildlife Summit generated.

        2. rork Avatar

          We get brown trout x brook trout hybrids in Michigan, but they are rare, and sterile so far. That’s a Salmo/Salvelinus cross (not a Oncorhynchus) and both are fall spawners, which probably helps allot. All these fish are family Salmonidae, but I know what you meant by Char family.

          Ralph probably just wrote too fast.

          1. Ralph Maughan Avatar
            Ralph Maughan

            rork and all,

            Yes, I made a typo. Here is an interesting story about a man catching a giant cutbow in American Falls Reservoir (about 20 miles west of Pocatello). The mother of this cutbow was a Yellowstone cutthroat.

            Pocatellan catches world record cutbow trout at A.F. Reservoir. Idaho State Journal.

      2. Mike Avatar

        Ralph –

        I’ve caught numerous cutbows in Yellowstone.

  7. JEFF E Avatar
    JEFF E

    Hopefully they are turning these into steaks and supplying area shelters, or alternatively making them available to area organic farmers as soil amendments

    1. alf Avatar

      The only time I’ve eaten lake trout was on a canoe trip in Bowron Lakes Provincial Park in British Columbia in about 1975 or so.

      One of the guys in our party of 6 trolled while we paddled down the lakes and caught a few, all about the same size — around 5 or 6 pounds each, as I recall. As I recall, they had white meat, were oily, and rather off-tasting — not very tasty at all.

      The rainbows, all in the 14 to 16 inch range, that I caught on my flyrod in the evenings and mornings at camp were excellent, however, with beautiful orange meat.

  8. Kayla Avatar

    Now I had read of this the other day, Great News! I remember how it used to be when all the creeks and streams going into Yellowstone Lake would be chuck full of Cutthroats. Wishing the Cutthroats a full comeback.

  9. BV Avatar

    Are there any fishing tournaments targeting Lake Trout held on Yellowstone Lake ? In addition to commercial netting and other current management practices, maybe promoting and holding yearly events would continue raising awareness and contribute to the effort ? Perhaps area Outfitters-Guides-Charters could get together with Yellowstone and state agencies to host such event(s) ? How about it ? -An educational-outreach festival with camping, fishing, music, AND LAKE TROUT COOKOUTS ?


Dr. Ralph Maughan is professor emeritus of political science at Idaho State University. He was a Western Watersheds Project Board Member off and on for many years, and was also its President for several years. For a long time he produced Ralph Maughan’s Wolf Report. He was a founder of the Greater Yellowstone Coalition. He and Jackie Johnson Maughan wrote three editions of “Hiking Idaho.” He also wrote “Beyond the Tetons” and “Backpacking Wyoming’s Teton and Washakie Wilderness.” He created and is the administrator of The Wildlife News.

Subscribe to get new posts right in your Inbox

Ralph Maughan