The United States Geological Survey (USGS) has begun an experiment on
Lake Minnetonka that could turn the tide in the war against zebra mussels.
The experiment centers around the use of a biopesticide called Zequanox in open water to kill the invasive zebra mussel. The USGS recently applied for and was awarded a grant to conduct the experiment through the Legislative-Citizen Commission on Minnesota Resources (LCCMR), and several local, state and federal agencies have approved experimental use of Zequanox on Lake Minnetonka.
The Lake Minnetonka Conservation District (LMCD) is not involved in the experiment.
The first-phase of testing, being carried
out in coordination with the Minnehaha Creek Watershed District, began
last week and will continue throughout the summer on Robinsons Bay.
"Details from the USGS on the study design have only become clear within the last couple of weeks," Eric Fieldseth, an aquatic invasive species specialist with the Minnehaha Creek Watershed District, wrote in a memo presented to the district's board of directors earlier this month. "Those details included the design of approximately 80 substrate samples, which were to be submerged on the lake bottom in Robinsons Bay."
Click here to read Fieldseth's memo in its entirety.
The substrate samplers were placed in three stockpiles in about 10 feet of water and marked with "submerged hazard" buoys. The substrates will remain in place until August, at which time they will be moved to "strategic" locations on the bay.
Zebra mussels attached to the substrate samplers will then be treated with Zequanox using a variety of techniques. The substrates will be removed in October, and scientists will analyze the results.
Barges owned by Gabriel Jabbour, a former mayor of Orono and member of the Department of Natural Resource's Aquatic Invasive Species Task Force, were used to place the substrates. Jabbour, owner of the Tonka Bay Marina, says he's optimistic the experiment will yield positive results and help conversationalists gain a foothold in their battle against zebra mussels.
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Nearly 100 Minnesota lakes have been confirmed to have a zebra mussel infestation.
Biologists hope the Lake Minnetonka experiment will determine Zequanox’s safety and efficiency in combating zebra mussels in “limited, high-value Minnesota waters.”
The study will include examination of the reproductive success of native fish populations and on the survival of native aquatic insects.
“Fathead minnows, a representative test species, and their eggs will be exposed to an environmentally relevant concentration and exposure duration, and the impacts on spawning and development will be assessed,” Mark Gailkowski, a USGS biologist spearheading the experiment, wrote in the agency’s grant application to the state.
A community meeting to discuss the project will
take place in late June or early July.
If successful, Zequanox could receive approval from the Environmental Protection Agency for use across the country in open waters. Zequanox is currently approved by the EPA for use in what are called defined discharges such as cooling systems used by industrial facilities.
The first of several reports detailing results of the experiment will be ready by December. Final results of the multi-year study will be presented in 2016. Cost of the project is estimated at $600,000.