Sea Grant Research Indicates Bacterial Toxin May Control Zebra Mussel

Zebra mussels first were identified in June 1988 in Lake St. Clair, having most likely arrived in the ballast water of ships from Europe. The Sea Grant National Aquatic Nuisance Species Clearinghouse estimates approximately $1 billion in damages in North America related to the spread of the non-indigenous aquatic mussel, which can cause major problems at water dependent infrastructure including electric power generation stations, water treatment plants, in irrigation systems, and other industrial and recreational facilities.

Since 1991, researcher Daniel Molloy has led a Sea Grant-supported effort to identify predators, parasites, and infectious microbes that can kill zebra mussels. In small trials, Molloy says the bacterium has eliminated the mussels in pipes at a hydropower facility with a 95 percent kill. The bacterium destroys a digestive gland within the mussel, leading to their death. Because even dead Pseudomonas cells kill zebra mussels, Molloy suspects that the bacterium contains a toxin within its cell walls.

He and his colleagues have conducted preliminary tests indicating that the microbe does not harm untargeted species, including fish and native mussels. They are now working to identify and purify the toxin. And then? Molloy says the big challenge will be to find a way to produce enough of the bacterium or its toxin commercially. "This research is the next logical step in the path toward commercialization of the bacterium as an innovative, ecologically-safe, and effective zebra mussel control agent."