Quagga Super-Mussel Quandary

From November 11, 1992 (update #15)

ZION, Ill. - The discovery in Lake Ontario of a second species of zebra mussel - dubbed the quagga mussel - was first announced by Ellen Marsden of the Illinois Natural History Survey and Bernie May of Cornell University at the International Zebra Mussel Research Conference last November in Rochester, N.Y. Since then, the quagga mussel has been sighted at a number of new locations. Spreading even more rapidly than these sightings have been newspaper accounts reporting the invasion of a "new super-invader," a phrase coined by USA Today reporter Rae Tyson in a Sept. 22 news report. Though featured in Tyson's story, Marsden noted that the conclusion that quagga mussels are "super-zebra mussels" is premature - and perhaps unwarranted. "Unfortunately, due to the interest generated about the potential impacts of this zebra mussel relative, several conjectures have been misinterpreted as facts," Marsden said. "To date, however, the only confirmed ecological data on the quagga mussel is that in Lake Ontario it is distributed deeper than zebra mussels - that is, the ratio of quagga mussels to zebra mussels increases with depth." Marsden noted that it is difficult to determine whether the quagga mussel will create additional problems to those caused by the zebra mussel without additional information about the species. "Broad-spectrum controls, such as chlorine and heat, are likely to kill the quagga as effectively as the zebra mussel, even if their tolerances are slightly different," she added. "However, narrow-spectrum controls such as taxon-specific pathogens and physiological agents may not work on both species." The quagga mussel is undoubtedly one of several Dreissenid mussels found in Europe. To date, no one has identified the species, but Marsden reported that colleague May has analyzed samples from a Russian population that is genetically identical to what has been dubbed the quagga mussel.

ID: 19921111-7.

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.