August 17, 2008

Avian Botulism Confirmed in Lake Michigan

Biologists have confirmed the first cases of avian botulism on Lake Michigan this year.

Four shorebirds that washed up at Ludington State Park in mid-July represented the furthest south that botulism has been found on the lake, although more than 8,000 birds died of the disease along northern Michigan last fall, the Detroit Free Press reported Sunday.

Avian botulism is not harmful to humans and occurs naturally in the Great Lakes where about 50,000 birds have died on Lake Erie and Lake Ontario since 1999. Scientists believe warmer water temperatures help create cladophora algae, which harbors the toxin. Invasive species, such as zebra and quagga mussels and round goby fish, then help spread it when eaten by birds.