IAGLR Conference Highlights

From July 15, 1993 (update #17)

DE PERE - The following zebra mussel ecological impacts were reported June 7-10 at the annual meeting of the International Association for Great Lakes Research at St. Norbert College:

Zebra mussels feed differently on toxic and non-toxic forms of the bluegreen alga Anabaena, according to University of Minnesota zoologist Don McNaught. Although zebra mussels filter both toxic and non-toxic forms of this alga out of the water at the same rate, they do not actually consume the toxic forms. Instead, McNaught reported, they produce more pseudofeces when toxic Anabaena is present, requiring them to expend energy without any nutritional benefit.

During the summer of 1992, zebra mussels were collected in Lakes Huron, St. Clair and Erie as part of a nationwide contaminant monitoring program. Initiated in 1986, the Mussel Watch program has monitored contaminant levels in the soft tissue of oysters and blue mussels at 240 sites along the marine coastline of the United States. In 1992, inland zebra mussel sites were added to the program to provide additional coverage. Two sites on Saginaw Bay, one on Lake Huron, one on Lake St. Clair and three on Lake Erie were sampled last summer. Collected zebra mussels were examined for 20 PCB congeners, 20 PAH congeners, tributyltin and almost a dozen trace metals. Total PCB levels in zebra mussels from several locations exceeded previously observed levels in marine molluscs. Overall, zebra mussels were found to concentrate these contaminants to about the same degree as their marine relatives.

ID: 19930715-5.

The Zebra Mussel Update was a 4- to 8-page quarterly national newsletter published by the University of Wisconsin Sea Grant Institute from May 1990 through May 1997. The ZMU documented the spread of the zebra mussel -- an exotic nuisance mussel -- through North America's freshwater environments, especially the Great Lakes, and on efforts to control it.