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Bleach set to eradicate Germantown's invasive crayfish

Germantown - Louisiana red swamp crayfish lurking in a village pond will be drinking Wisconsinbleach this week in a continuing battle between the invasive species and state environmental officials.

Bleach poured into the storm-water pond and a smaller nearby pond should kill the rapidlyreproducing intruders there, even as the state Department of Natural Resources prepares to take on a

second infestation of the large crayfish in Wisconsin, said Randy Schumacher, DNR regional fisheriescoordinator in Milwaukee.

The nuisance intruders were discovered recently in an urban fishing pond at Sam Poerio Park inKenosha, and a fabric fence has been erected along the shoreline to prevent the aliens from crawlingto other nearby water bodies, Schumacher said.

The DNR's first priority is eradicating the invasive crayfish in Germantown.

On Thursday or Friday, nearly 4,000 gallons of bleach will be poured into the Esquire Estatessubdivision pond off Western Ave. to kill any of the Gulf Coast crayfish that have evaded traps, hesaid. The chemical will kill minnows and other aquatic life that might be in the pond, which is not anatural lake.

This invasive species of crayfish - much larger and more aggressive than native crayfish - wasreleased illegally into the pond earlier this year, Schumacher said. The big crustaceans grow up to 8inches long, and they would replace the locals quickly.

Investigators have not determined who released the aliens or why, Schumacher said. The crayfishmight have been tossed into the pond by someone who ordered too many for a Cajun-style meal orpurchased them for pets.

"No one should be releasing any animal outdoors without a permit from the DNR," he said.

State officials became aware of the Germantown infestation - the first time the species has beendocumented in Wisconsin - after subdivision residents reported the crayfish crawling over lawns in lateAugust. Those residents say they had not seen the crayfish before July of this year.

More than 2,000 have been removed after they were captured in traps baited with beef liver, saidJamie Lambert, a DNR water resources specialist. Lambert and two other DNR workers removed 87red swamp crayfish from traps on Thursday.

At least 120 traps have been placed along the pond shoreline and the shore of a small island in thepond, Lambert said.

Some of the females are releasing eggs, and Schumacher confirmed the prolific alien is reproducing inGermantown.

Red swamp crayfish burrow into mud on the pond bottom and could spend the winter. For that reason,the DNR received the authority to pour sodium hypochlorite - bleach, in this case made by HydriteChemical Co. of Brookfield - into the pond and a second, smaller storm-water pond on the oppositeside of Western Ave., south of the Village Police Department. The two ponds are connected by adrainage ditch.

On the day the work is done, a tanker truck will park on Western Ave. and the DNR will employ threeboats - two that will move around the Esquire Estates pond, injecting a bleach solution below thesurface, and a third that will inject a more concentrated solution directly into crayfish burrows.

A total of 3,740 gallons of bleach mixed with water will be poured into the Esquire pond. An additional70 gallons of the bleach solution will be poured into the pond at the Police Department.

This battle, though small in scale, is frustrating and time consuming to deal with, Schumacher said.

The state Department of Agriculture, Trade and Consumer Protection will accept public comments onthe bleach treatment until Tuesday. A special pesticide notification proposed by the agriculture

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Bleach set to eradicate Germantown's invasive crayfish

department authorizes the DNR to use higher concentrations of bleach in the pond than the raterecommended on the product label.