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Still, with a little luck (and an increase in predation by native fish like the freshwater drum), the zebra mussel may yet be brought under control. In fact, some evidence suggests that the mussel population in Lake Erie may have peaked. "There are many ways to kill the zebra mussel," observes Ohio State entomologist Susan Fisher. "The trick is to do it selectively" without wiping out other aquatic life. Fisher has recently found that minute traces of potassium, nontoxic to other organisms, reliably send zebra mussels into fatal shock. Paints laced with potassium, she speculates, might protect underwater structures from mussel infestation. Physiologist Jeffrey Ram of Wayne State University in Detroit makes an even more devious suggestion. Zebra-mussel spawning, he notes, is triggered by odors wafting from phytoplankton. These chemical cues ensure that the eggs hatch when the food supply is plentiful. But what if synthetic scents were dabbled like perfume above the mussel beds? A premature spawn, says Ram, would surely doom most of the larvae.
"I do not understand this talk of killing," counters biologist Anna Stanczkowska-Piotrowska of Poland's Agricultural-Pedagogical University. The zebra mussel, she points out, is not without virtues. Its byssuses extrude an adhesive that may have commercial value. Its appetite for foul-smelling algae can markedly sweeten the taste of drinking water. Perhaps most admirable of all, the zebra mussel has performed an act of public service by dramatizing the threat posed by tiny organisms that hitch rides around the world. Both the U.S. and Canada are moving to restrict the discharge of ballast water into the Great Lakes, a measure of ecological prudence that is long overdue.