Editor's Note

From October 11, 1991 (update #11)

Zebra mussel reproduction slowed down in Lake Michigan as cooler temperatures prevailed during September and early October. Yet the Sept. 12 discovery of a single mussel in the Mississippi River at La Crosse, Wis., was the first indication that 1992 will bring another wave of new zebra mussel sightings in Wisconsin as these invaders enter the Upper Mississippi River watershed. Almost as surprising was the continuing low numbers of zebra mussels in Superior harbor, where their abundance remains similar to the summer of 1990. From Aug. 31 to Oct. 4, zebra mussel larvae (veligers) were detected in nearly a third of 34 harbor and 69 water intake samples in Lake Michigan, and post-veligers were found on slightly less than half of the substrate samplers taken from that lake. During that same period, veligers were found in Lake Superior in only 1 of 12 harbor samples and in none of 6 water intake samples, and post-veligers were found on only 3 of 13 substrate sampler from that lake.

ID: 19911011-1.

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.