More dead fish in Wisconsin – 06/25/2005

  • October 23, 2013 at 3:30 am #742

    from arufon – ‘

    Dead fish? Hold your nose and wait
    By David Steinkraus

    There’s nothing wrong with the inland lakes that a little time won’t
    cure. Until then, it’s advisable to hold your nose if you find the
    odor of decaying fish offensive.

    For about the last week, the Department of Natural Resources office
    in Sturtevant has been hearing complaints about dead fish on Eagle,
    Silver, and Beulah lakes in Racine, Kenosha, and Walworth counties.
    But this is nothing out of the ordinary and is the result of factors
    that always converge about this time of year, said Doug Welch, the
    fisheries biologist for the three-county area. “And some years are
    worse than others. It all depends on how fast the water temperature
    rises, how much rain we get, and that sort of thing.”

    The other factor is that fish are spawning now. The stress of that
    reduces their resistance to infection, Welch said. At the same time,
    warmer water induces the rapid growth of microorganisms, specifically
    a bacterium called columnaris. It destroys gill tissue. Fish
    afflicted with this bacterial infection typically have a yellow mucus
    on parts of their gills or fins, usually surrounded by an area tinged
    red, and sloughing skin. (There’s no danger to humans from
    columnaris, the DNR says.)

    While columnaris lives in the water naturally, Welch said, their
    numbers are increased when rains flush the surrounding land, washing
    more bacteria into lakes.

    Typically it’s panfish — bluegills, pumpkinseeds, and perch — which
    contract the disease and which you’ll find dead, Welch said. Any fish
    is probably susceptible, but we see more panfish dying because
    they’re spawning now and they congregate in shallow water, he said.

    “These fish are done spawning, usually, by mid to late June,” Welch
    said. After that people may see dead fish, but not in the numbers
    visible now, he said.

    As to cleaning up the mess, Welch said, the DNR usually let’s nature
    take care of that, too, in the form of raccoons, opossums, gulls, and
    other scavengers.

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