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Thousands of Bluebills Dead since Thursday 11-1-07

Discussion in 'Wisconsin Waterfowl Hunting' started by HappyHawk, Nov 7, 2007.

  1. Thousands of bluebills dead since Thursday
    Sam Cook
    Duluth News Tribune - 11/06/2007

    Dan Markham and Noel Hill of Duluth, MN were setting up to hunt ducks on Lake Winnibigoshish near Deer River on Saturday when they noticed a dead bluebill on shore. A quick walk along the shore turned up another three dozen dead bluebills.

    Waterfowl biologists with the Minnesota Department of Natural Resources estimate that as many as 3,000 bluebills, also known as lesser scaup, may have died along the west shore of Lake Winnie.

    The die-off began Thursday, said Steve Cordts, DNR waterfowl specialist in Bemidji. Biologists believe the cause is a microscopic trematode, a kind of fluke, present in snails that the bluebills are feeding on.

    Cordts thinks the die-off could continue. “We’re going to find a lot more dead,” he said in a telephone interview Monday.

    Cordts and other DNR employees collected about 1,000 dead bluebills from a stretch of shoreline on Friday. In the time it took to collect about 900 of those birds, another 30 to 50 had died in the same stretch.

    “This is potentially pretty bad because of this snail,” Cordts said. “The trematode is likely brand new to the system. It could be along the whole stretch of the Mississippi River and could get into other lakes and into other species. It’s way too early to speculate a lot.”

    “We were just heartbroken,” Markham said. “It’s depressing.”

    The die-off also has affected coots, Cordts said, although most coots have already left Lake Winnie. He didn’t know how many bluebills remained on the lake.

    The snail that apparently is a host of the trematode is the banded mystery snail, Cordts said. It was first documented on Lake Winnie eight years ago by fisheries biologists.

    “It’s been concentrated on the west side [of the lake],” he said. “Its numbers have really exploded.”

    Die-offs of waterfowl due to trematodes have occurred in the spring and fall since about 2002 on the Mississippi River near Winona, Minn., Cordts said, though not in numbers as high as those on Lake Winnie.

    DNR officials sent a few ducks to the National Wildlife Health Center in Madison, Wis., on Thursday. An initial inspection turned up the trematode identification in one duck, but DNR officials were waiting Monday for confirmation of that in other samples.

    Hunters or others should not eat any duck that appears to be obviously diseased, Cordts said. Hunters should use latex gloves when cleaning their ducks.

    Cordts said he doesn’t know of any other major waterfowl die-offs due to trematodes other than those near Winona. Controlling the snail that serves as a host would be “almost impossible,” he said.
     
    Last edited by a moderator: Nov 7, 2007
  2. UPDATE - Now 6000 + dead

    Scaup kill on Winni grows to 6,000
    By Doug Smith, Star Tribune

    Last update: November 08, 2007 – 4:20 PM


    Nov. 6: Parasite has killed thousands of scaup
    The number of dead scaup, or bluebills, on Lake Winnibigoshish in northern Minnesota now might number as many as 6,000 according to the Department of Natural Resources.
    More dead birds are expected before the fall migration is over.

    Thursday afternoon, a large raft of live scaup were on the lake, said DNR waterfowl biologist Steve Cordts, who feared the birds might also ingest a parasite infesting snails in the lake and die.

    Cordts' colleague, Jeff Lawrence, was flying over Winnibigoshish Thursday afternoon and when he returned expected to have a more exact estimation of how many birds have died.

    Cordts and the DNR picked up 1,000 dead scaup beginning last Saturday.

    He saw many other scaup still alive at the time but unable to fly, or to fly far. "You could boat right up to them," Cordts said. Perhaps 3,000 ducks, mostly scaup, and some coots have died in the past week.

    The ducks apparently are dying from trematodes, a tiny 1-millimeter intestinal parasite or fluke that has infected snails in the lake. Scaup -- a duck that dives below water to feed -- eat the snails, then are infected.

    "They essentially bleed to death," Cordts said.

    The parasite was confirmed in scaup and coots sent to the National Wildlife Health Center in Madison, Wis.

    Similar die-offs caused by trematodes have occurred spring and fall since 2002 on the Mississippi River near La Crosse, Wis., killing about 40,000 ducks and coots since then. Die-offs again are occurring there this fall.

    Cordts said he's not sure how the trematodes made it to Winnie. They apparently have infected a snail called the banded mystery snail, which was first found on Winnie about eight years ago. They are infecting the faucet snail on the Mississippi.

    Officials aren't sure how many ducks might eventually die on Winnie, or what impact, if any, it will have on the scaup population. But Cordts is concerned that the snails and parasites might spread to other Minnesota waters.

    Other duck species also could eat the snails and become infected, he said.

    There is concern because the continental scaup population has been declining since 1984 and hit an all-time low last year at about 3 million. Hunters annually kill about 300,000. Minnesota hunters killed about 20,000 last year.

    Lake Winnibigoshish is a major scaup resting area during migration. "We could have 20,000 scaup show up on Winnie right now," Cordts said. "If that happens, they'd pretty much all be at risk."

    Cordts won't collect any more dead ducks. Instead, carcasses will be left to decompose or be eaten by scavengers. The parasite apparently is not a threat to other species, including humans, but Cordts said hunters shouldn't eat sick waterfowl.


    Doug Smith • dsmith@startribune.com
     
    Last edited by a moderator: Mar 20, 2015