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Loons dying across Great Lakes

Minnesota’s state bird, the loon, is dying by the thousands across a growing portion of the Great Lakes because of a bacterial disease that starts from the lake floor.
The Star Tribune is following developments in the story, noting that officials are concerned about the potential for deaths around the Duluth-Superior harbor.
While the issue was first noticed in the eastern portion of the Great Lakes chain eight years ago, loon deaths are now spreading west; Lake Superior hasn’t been affected yet, however.
This year the area of dead loons has spread to hundreds of miles of Lake Michigan shoreline.
It can’t be determined how many of the birds have died during the past several years because no one knows how large their populations are in northern Canada, according to Helen Domske, an extension specialist for the New York Sea Grant.
Domske guesses that thousands have either died and sank or washed up in remote areas and never counted. Based on those that are collected and bagged, Michigan, Ontario, New York and Pennsylvania have had “substantial? die-offs this year.
Scientists think that the loons are killed by Type E botulism that makes its way up the food chain from the bottom of the lake.
Toxic bacterial cells work their way to loons through quagga mussels and round gobies, a type of fish. Because these mussels and gobies are not native to the Great Lakes, the issue has been called another unseen threat from invasive species.
Research is also being done to determine whether higher lake temperatures and lower water levels in recent years have stimulated plant growth and therefore increased plant growth.