Carp devastate waterfowl at Malheur Lake

Rotenone has been used a number of times on carp at this national wildlife refuge, but it never gets them all.  Once again there over a million carp. Is there any long term solution?

Explosion in carp numbers have caused big drop in birds at eastern Oregon refuge. By Richard Cockle, The Oregonian





  1. Tilly Avatar

    Sad. And the Refuge has a lot more problems, too. The intensive water management sure is depressing: straight-line channels and headgates everywhere. Does not look very natural. Also the Refuge allows haying and grazing. They have propaganda signs posted explaining why water control, haying, and grazing are needed for the birds. They claim that “The removal of vegetation allows solar heat to warm up the soil early in the spring.”

    The Refuge is in the process of redoing its management plan right now. Interested parties should be sure to weigh in.

  2. Paul White Avatar
    Paul White

    Pull out native fish, kill everything (blasting, toxins, god knows what), clean the water, replace native fish? It’s the Ridley Scott school of ecological management I guess, but how else do you kill ’em? And no one fishes for carp so fisher-folk won’t be a huge help I don’t think…

  3. vickif Avatar

    Carp are prolific breeders and can endure many of the environmental challenges other fish cannot. They are truly junk eaters. They can also be difficult to catch.
    The lake may need to be killed, dredged, and re-established.
    So sad, it is a problem that is pretty common I would suspect.

  4. SEAK Mossback Avatar
    SEAK Mossback

    With that kind of biomass, it sounds like commercial fishing might be part of the solution if selective methods can be employed that don’t take native fish species or kill birds. It might take some subsidy to keep it going at an intensive enough level that holds the carp population down enough to have significant ecological benefits, but certainly no less appropriate than the grazing subsidies or subsidies to build logging roads into old growth stands.

  5. Ralph Maughan Avatar

    I received the following comment by email. It is important.

    Subject: Carp in Malheur lake
    Date: Wed, 2 Jun 2010 16:59:18 +0000
    Another remarkably data-free and assumption-laden press release.

    Neither the biologist nor the reporter have connected the reduced number of birds with the carp in any way that would show the former to be the result of the latter.

    Having looked at numbers of migrating and returning birds at Malheur almost yearly since 1972, I quite agree that numbers are down very significantly.

    Way down.

    And I’m willing to believe that carp in high densities can negatively impact waterfowl reproduction.

    But in this case, the birds that normally migrate through and nest at Malheur -including ducks- just aren’t present in numbers even close to those were seen historically. With the exception of White-faced Ibis, numbers of all water birds -including curlews, herons, gulls, terns, avocets and stilts, even coots- are not nearly as high as I saw in most of the seventies, eighties, nineties, and earlier in this decade. This was true for the last two years as well. Many of the species that are down cannot be connected to carp numbers, and numbers are down everywhere, including the pastures that flank Highway 205 north of the Refuge, where typically thousands of birds are found at this time of year, where there are no carp. And everything, including passerine birds like blackbirds, wrens, and yellowthroats, are much reduced. And all of the latter are hugely separate from carp ecologically.

    And birds that eat fish (including carp), like pelicans and cormorants, are down as well. And numbers of all birds are down in recently flooded (i.e. recently “watered”) areas on the Refuge far from any carp populations.

    If carp were responsible for this, one would expect the mechanism to be lowered reproduction. It’s difficult to imagine ducks flying over, spotting carp, and deciding to move on. But the article says nothing about data showing a series of years of lowered reproductive success preceding and leading to the reduced numbers.

    By implying that carp are responsible, the Service is grasping at straws, and setting the stage for another pesticide program, and deflecting responsibility to seek a biologically responsible explanation. It is interesting, though, that they are willing to admit that their earlier use of rotenone (these were usually called “eradication programs”) was ineffective. Judging from the comments on this article, they have been successful in riling up the citizenry and focusing xenophobic attention on the carp.

    This is irresponsible biology and irresponsible journalism, in my view.

    But it is an intriguing and tragic mystery. It would be interesting to know how widespread this collapse is (does it extend to the Klamath Basin, for example?) and it begs for rational analysis.



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.

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Ralph Maughan