Marrone Bio Innovations, Inc. (MBI) has announced the successful results of a Zequanox treatment conducted at Christmas Lake in Shorewood, Minnesota.
Minnesota Department of Natural Resources and the Minnehaha Creek Watershed District’s (MCWD) Aquatic Invasive Species (AIS) Program requested Zequanox treatment from MBI after discovering zebra mussels near the public boat launch. The non-chemical product approved for use in open water was applied to a 50 by 60 foot containment area with an average depth of 2.5 feet. Before treating, there were approximately 5,000 live mussels in the enclosure. The treatment began on September 8 and eleven days later results showed 100 percent mortality of the zebra mussels in the treatment area.
“We are extremely pleased that Zequanox was so effective in the Christmas Lake treatment,” said Keith Pitts, Vice President of Regulatory Affairs for MBI. “The watershed district and the Minnesota DNR have been great partners, and we’re happy to continue to see proven results for invasive mussel control. It’s a comforting outcome for the public as well, because this solution is more environmentally friendly than other mussel control products and can be administered without harming people, pets or the environment.”
MCWD staff monitored the effectiveness of Zequanox by counting dead mussels over time in the treatment area using collected mussels placed in cages and by searching the area for mussels attached to rocks. Also, they monitored aquariums in a laboratory that held treated water and mussels from Christmas Lake.
“Marrone Bio Innovations has been a key partner in the first phase of our response,” said Craig Dawson, director of MCWD’s AIS Program. “What we’ve learned from the treatment bodes well for future efforts to contain zebra mussel infestations, especially when they’re caught early like the Christmas Lake case.”
Invasive mussel populations are now prevalent in major waterways throughout the country, including the Great Lakes Region as well as the Mississippi, Arkansas, Tennessee and Colorado rivers. The mussels have a significant economic and environmental impact on recreational water use. Colonies of invasive zebra and quagga mussels negatively impact native mussel populations, disrupt the natural ecosystem and cause proliferation of toxic blue-green algae. They decrease game fish populations, which can have a serious effect on the economic health of the fishing industry. Swimmers run the risk of injury from the invasive mussels’ sharp shells, and water intakes from infested lakes and rivers used for irrigation, fire suppression and drinking water can suffer impeded or blocked flow and damage to infrastructure and equipment.
Zequanox is the industry’s only selective and environmentally compatible molluscicide, which was first approved by the EPA in 2012 for mussel control in enclosed systems and infrastructures for energy producers, manufacturing companies and golf courses. The EPA approved Zequanox in July for open water use and as a result, the product is now available to private waterfront owners and natural resource managers as an effective solution to control existing populations of invasive mussels or knock back new infestations without the use of environmentally harmful treatments, such as potash and copper-based products.
Composed of dead cells derived from a naturally occurring soil microbe, Zequanox controls mussels in all life stages. Unlike toxic treatments, such as potash and copper-based solutions, Zequanox is biodegradable and noncorrosive. In addition, Zequanox is highly selective to control only the invasive zebra and quagga mussels, is effective in a broad range of water conditions and according to the EPA, its active ingredient has “low toxicity and presents little risk to non-target organisms.”
Zequanox is applied directly into an open body of water, such as a lake or river, using standard injection equipment. Treatments can occur during any time of the day while people and pets are present, and can be completed within hours. The product offers additional flexibility because it is proven to be effective in a broader range of water conditions.
The product offers a zero hour re-entry interval, so there is no waiting period after treatment that might interfere with commercial or recreational use of a waterway, such as fishing, swimming or boating. The U.S. EPA determined Zequanox was exempt from the requirement of a food tolerance, which indicates that there is no concern with using treated water to irrigate crops or that eating fish caught in waters treated by Zequanox poses any risk to consumers.
Traditional chemical products do exist to effectively treat invasive mussel populations, however they can leave damaging environmental impacts. Solutions containing potash (potassium chloride, KCI) and copper based products can kill endangered and threatened native mussel species. Also, use of potash- and copper-based products lead to public heath concerns resulting in restricted drinking water use from reservoirs and prohibitions on recreational use for extended periods. Both chemicals are toxic to non-targeted organisms and persist in the environment, causing prolonged ecosystem exposure.