Editor's Note

From November 11, 1992 (update #15)

Zebra mussels spread into Wisconsin waters of the Great Lakes at a slower rate than expected during the summer of 1992. Settled mussel densities increased in Wisconsin waters of Lake Michigan south of Port Washington, but in Green Bay and northern Lake Michigan similar densities were seen as during the previous summer. The biggest expansion of zebra mussel populations occurred Wisconsin waters of the Mississippi River. The only sign of zebra mussels observed in Lake Superior was a single mussel found Sept. 22 on one of 94 substrate samples from Superior harbor. No veligers (mussel larvae) were found in any of 40 harbor and 49 water intake samples from that lake. No zebra mussels were found in the 35 plankton tows and about 50 substrate samples from Lake Winnebago. No confirmed sightings of zebra mussels in Lake Winnebago have occurred to date. From June 15 through mid-October, veligers were detected in 97 of 156 (62%) harbor samples and 105 of 183 (57%) water intake samples from Lake Michigan. Recently settled post-veligers were found on 95 of 134 (71%) substrate samples examined from that lake.

ID: 19921111-1.

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.