Lake Michigan Veliger Densities Drop with Fall Temperatures

From October 11, 1991 (update #11)

Zebra mussel veligers were no longer being detected in water samples taken in early October from the water utilities at Cudahy, Kenosha, Milwaukee, Oak Creek, Port Washington and South Milwaukee, according to Zebra Mussel Watch scientists. Small numbers of veligers were still showing up in samples from the Racine (Wis.), Grand Rapids (Mich.), Muskegon (Mich.) and Northshore (Milwaukee) water utilities in late September. No veligers were detected all summer in intake samples from the Green Bay (Kewaunee location), Manitowoc, Marinette, Sheboygan and Two Rivers water utilities in Wisconsin. Wisconsin harbor water samples showed a similar trend: by late September, no veligers were being detected in samples from Green Bay, Kenosha, Manitowoc, Port Washington, Racine and Sheboygan. No veligers were found in any of the harbor water samples collected this summer from Kewaunee, Marinette, Lake Winnebago and Sturgeon Bay. Milwaukee harbor water samples continued to show barely detectable numbers of zebra mussel veligers through late September.

ID: 19911011-5.

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.