Crystal Lake Mixing Project aims to eradicate invasive species - WAOW - Newsline 9, Wausau News, Weather, Sports

Crystal Lake Mixing Project aims to eradicate invasive species

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VILAS COUNTY (WAOW) -- Beautiful, serene Crystal Lake. 88 acres of crystal clear water. The lake is beloved by tourists and natives who live there. But there's a type of species outdoors experts are hoping doesn't become native, and they're working overtime to rid it from the waters. Researchers from UW-Madison have zeroed in on the invasive rainbow smelt. Introduced into the Great Lakes system more than 70 years ago, it has made its way to inland lakes, feeding on young fish and larvae.

"The yellow perch both compete with smelt for the same foods. Also, when yellow perch hatch, in the early part of the year, the rainbow smelt will prey on those perch. So, they have a negative effect on the yellow perch populations and the same goes for walleye," said Eric Brown, a project researcher.

The impact has researchers testing a new technology. The Gradual Entrainment Lake Inverter or GELI mixes the cooler 50 degree bottom water with the warmer 70 degree surface water.

"These things sit at the bottom of the lake and we have airlines connecting to that middle bubble and we fill it with water, that causes the GELI to rise through the water column," said Zach Lawson, a research associate.

"Dense water will always flow towards the deepest part of the lake. So, if we mix it and raise that deep water temperature, cold water from other parts of the lake will flow towards that central mixing area," said Brown.

In three phases over the next three years, researchers will mix the water using the GELI system. Phase one: killing the adults. Phase two: eradicating the offspring those adults reproduce. And, Phase Three: quality assurance.

"We should be able to push the rainbow smelt past their thermal tolerance and cause them to die off," Lawson said.

While it's unclear how rainbow smelt get inland, 25 lakes in Wisconsin have been invaded and 500 have suitable habitats. It's a risk previously corrected by poisoning entire bodies of water, resulting in the death of everything in it. With rainbow smelt preferring colder water this could be a natural resolution.

"The idea is that we can provide the DNR and other lake managers with a tool that they can completely eradicate rainbow smelt and any detrimental negative effects on the native community," said Lawson.

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