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Zebra mussels found in Brophy and Cowdry lakes

Minnesota Department of Natural Resources (DNR) biologists have confirmed a report that zebra mussels are now in Brophy and Cowdry lakes near Alexandria.

Brophy and Cowdry are part of a small chain of lakes less than a mile upstream of Lake Darling and the Alexandria chain of lakes, which were confirmed to have zebra mussels in June 2009.

A local homeowner found several zebra mussels attached to rocks in Brophy, nearby his property, and reported it to the DNR. The DNR surveyed Brophy and downstream in Cowdry and found young zebra mussels in both lakes.  

"It is very disappointing that zebra mussels found their way into this small chain of lakes," said Nathan Olson, DNR invasive species specialist in Fergus Falls. "Everyone needs to take extra precautions not to transport these pests to other waters in the area."

In response to this new infestation, the DNR will:

• Designate the chain of lakes including Brophy, Union, Stoney, Taylor and Cowdry as infested waters. This designation prohibits the transport of water and also prohibits the harvest of bait

• Place new signs at public water accesses on Brophy Lake and Lake Cowdry to indicate the presence of zebra mussels

• Increase enforcement and watercraft inspections efforts

• Inform residents and business of how they can help prevent the spread of the invasives.

Additional surveys are planned. Also, it is not known how widespread zebra mussels are in the other connected lakes. The young age of the zebra mussels suggests that a reproducing population likely has been in Brophy and Cowdry lakes for at least a year. 

Prior to this discovery of zebra mussels, the DNR worked with the Douglas County Lakes Association and others in the Alexandria area to inspect boats and educate lake users. The efforts were aimed at involving the public in helping prevent the further spread of invasive species into other Alexandria area lakes.

A nonnative invasive species, zebra mussels pose serious ecological and economic threats to Minnesota's lakes and streams. Heavy infestations can kill native mussels, impact fish populations, interfere with recreation, and increase costs for industry, including power and water supply facilities. Native to Eastern Europe and Western Russia, zebra mussels were first discovered in Minnesota in 1989 in the Duluth harbor.

Boaters are required by law to:

• Remove aquatic plants and zebra mussels from boats and trailers

• Drain all water, including pulling the drain plug, opening water draining devices, and draining bilges and live wells. The drain plug has to be removed or open when transporting your boat

• Drain bait buckets when exiting lakes. Anglers can keep unused bait when leaving infested waters if they replace the lake water with tap or spring water.

The DNR also recommends people spray or rinse boats with high-pressure and/or hot water, or let them dry thoroughly for five days, before transporting to another body of water.

The DNR has recently begun accelerating its efforts to prevent the spread of zebra mussels and other aquatic invasive species, including launching new inspection and decontamination procedures at several large lakes with zebra mussel infestations and high boat traffic.

More information about aquatic invasive species is available on the DNR website.