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Contact: Sue Jennings, 231-326-5134
Biologists at Sleeping Bear Dunes National Lakeshore (National Lakeshore) are closely monitoring what appears to be a new botulism-related bird die-off along the park shoreline. Although the cause of the die-off has yet to be confirmed, all indications point toward another botulism Type E (Avian Botulism) outbreak as the likely culprit. Hundreds of carcasses of the non-native round goby fish, which are believed to carry the botulism toxin and transmit it to birds when eaten, have been discovered on some beaches in the National Lakeshore, and a dead cormorant and herring gull have recently been found.
The National Lakeshore is currently conducting a study of botulism Type E to determine whether there are any steps that can be taken to control outbreaks. Dead birds and fish are identified, counted, and buried along the beaches when possible. Some dead animal specimens are also collected for study and laboratory analysis. Volunteers are being sought to assist with the National Lakeshore’s beach monitoring program. Informational meetings for prospective volunteers will be held from 2:00-4:00 p.m. on Friday, June 18 and again on Wednesday, June 23 at the National Lakeshore’s Visitor Center, 9922 Front Street, in Empire. If you are interested in volunteering and attending a meeting, please contact Park Ranger Emily Tyner at 231-334-7685.
Lake Michigan beaches within the National Lakeshore remain safe for swimming and recreation, however, park visitors should exercise caution upon encountering bird or fish carcasses. Type E botulism is not an infectious disease. It is a poison. You must ingest the toxin, usually by eating an infected fish or animal, to become ill. You are not at risk for contracting botulism by swimming in Lake Michigan. Visitors bringing pets to the park should keep them away from dead animals on the beach. Pets may be poisoned if they eat dead birds or fish containing botulism toxin.
Avian botulism is a paralytic, often fatal disease of birds that results when they ingest toxin produced by the native Clostridium botulinum Type E; an anaerobic bacterium found in nutrient rich substrates. The bacterium spores (resting stage of the bacteria) are abundant in many North American lakes. The spores are found in the gills and digestive tracts of fish living in these lakes and can remain viable for years; they are harmless until the correct environmental conditions prompt them to germinate. Type E botulism occurs only under conditions when these spores germinate, the bacteria multiply, and the vegetative cells produce toxin. Changes in Great Lakes ecosystems have increased the growth of the botulism bacterium. Birds are often poisoned by eating fish or invertebrates that contain the toxin.
In addition to actively monitoring the shoreline for sick and dead birds, the park is collaborating with scientists from the U.S. Geological Survey, the University of Wisconsin-Milwaukee, the University of Michigan, and Northwestern Michigan College’s Water Studies Institute, to conduct studies in the Lake Michigan nearshore environment to better understand the mechanisms of toxin transmission. Many of these studies are funded through President Obama’s Great Lakes Restoration Initiative to assure that Great Lakes beaches, fish, and sources of public drinking water are safe, and that the ecosystems that fish and wildlife depend upon are healthy.
For more information, please contact the National Lakeshore at 231-326-5134.