Type E Botulism on the Great lakes – Fall 2011

Since mid-August, dead fish and birds have been appearing on the beaches in Nottawasaga Bay in southeastern Georgian Bay on Lake Huron. An estimated 200 or more sturgeon, as well as whitefish and other species, have washed up on shore. Diagnostic tests on the one sturgeon examined were inconclusive, but were suggestive of a bacterial infection.

From mid-September onwards, the number of dead birds observed began to increase, reaching a peak on the weekend of 22-23 October, during which thousands of dead and dying birds were present on the beaches. Species involved included various grebes, Common Loons, Long-tailed Ducks, scoters, goldeneye and several species of gull. Birds collected at 4 different times during these 2 months have now been examined, and while test results are still pending in most cases, botulism has been confirmed in Herring Gulls from Christian Island.

Elsewhere, on the lower Great Lakes, Type E botulism was confirmed in late July in a Lesser Black-backed Gull from Point Pelee, and reports of mortality suggestive of botulism have recently been received from the vicinity of Long Point on Lake Erie and Newcastle on Lake Ontario.