From the Emmet County Lakeshore Association Fall 2010 Newsletter:
During the fall of 2007 there was an estimated 8,000 – 10,000 water birds that were believed to have died from botulism poisoning along the northern Lake Michigan shoreline. These water birds included loons, gulls, and all ducks, local and migratory in Lake Michigan.
There is the chain of events leading up to the botulism toxin poisoning of sea birds:
1) Botulism is naturally occurring on the lake bottom.
2) Mats of Cladophora algae (the same algae that is thick along the Lake Michigan beach) are believed to be caused by clearer water, caused by the invasive zebra and quagga mussels’ filtration of plankton from the water and from the mussels’ excretions causing the fertilization of the algae. These mats create an anaerobic condition on the lake floor which causes the botulism to produce a toxin.
3) The toxin is ingested by the mussels.
4) The invasive mussels are then eaten by the invasive round goby fish.
5) The dead round goby fish float to the surface and are eaten by sea birds.
6) The toxin causes a paralysis and the birds die from drowning or exposure.
This past Summer of 2010 there were reports of dead Round Gobies washing up on shore. This Fall there have been several reports of sea bird die-offs. Mark Breederland of Michigan Sea Grant reported 25+ dead Red-Necked Grebes in the vicinity of Brevort River in Mid September. Based on these reports, it is believed that it could be another year of botulism deaths of fish eating birds migrating along Lake Michigan. If dead birds are found DO NOT touch with bare hands to dispose of the carcass. Dead birds should be handled with gloved hands and can be placed in garbage bag for disposal or buried with a shovel. PLEASE check the birds leg to see if it is banded. CALL 906-370-1231 if it has a band on its leg.