Lee Bergquist

Milwaukee Journal Sentinel

The state Department of Natural Resources says starry stonewort, a fast-growing invasive aquatic plant that can upend the ecosystem in affected lakes, has been found for the first time in Lake Michigan.

The DNR said that the plant has been found in Sturgeon Bayin Door County. It's the first time the plant has been found in another area of the state outside of six lakes in southeastern Wisconsin.

The discovery of starry stonewort in Sturgeon Bay, a popular boating area, raises concerns about the plant spreading via boats to other parts of the state, according to the DNR.

"Given Sturgeon Bay's popularity as a destination for recreational boaters and anglers from across the region, starry stonewort has the potential to spread to many new lakes," Bob Wakeman, the DNR's aquatic invasive species program coordinator, said in a statement.

Starry stonewort was discovered during a routine aquatic plant monitoring survey by a contractor for the City of Sturgeon Bay. The city sent photos to the DNR, which confirmed the identity of the plant with the help of the New York Botanical Garden.

In an interview, Wakeman said the plant was found in about 20 different patches of Sturgeon Bay from the city north to Green Bay.

He said that more study is needed to determine the extent of the spread.

DNR officials are speculating that starry stonewort entered the bay via a commercial lake carrier or a recreational boat.

If starry stonewort acts like other invasive plants, it will be able to survive in 15 to 20 feet of water, but not much deeper because of the lack of sunlight.

"I don’t think you are going to see this spread across the bottom of Lake Michigan," he said.

In November 2014, DNR officials announced that starry stonewort had been discovered for the first time in Wisconsin in Little Muskego Lake in Waukesha County.

It has since been found in Big Muskego Lake in Waukesha County, Long Lake in Racine County and Silver, Pike and Green lakes in Washington County.

It was first discovered in the U.S. in the St. Lawrence River in 1978 and has been found in parts of the eastern Great Lakes and inland lakes of Wisconsin, Michigan, Indiana and Minnesota.

Native to Europe and Asia, the plant can take hold in a lake, choking out other vegetation. It is known for growing in dense mats that crowd out native plants and habitat for young fish.

Wakeman said boaters should take precautions so starry stonewort does not spread.

Wisconsin law requires all boaters to inspect their boats, trailers and equipment and to remove aquatic plants, animals and mud from them. The DNR says boaters should also drain water from boats.

There are control methods, including the use of chemicals and physically removing the plants from an area with suction, but Wakeman said no option is 100% effective.