TRAVERSE CITY, Mich. — The Supreme Court refused Tuesday to order the immediate closure of shipping structures near Chicago to prevent Asian carp from infesting the Great Lakes, before authorities said DNA from the ravenous invaders had been found in Lake Michigan for the first time.

The court rejected Michigan’s request for a preliminary injunction to shut the locks and gates temporarily while officials and interest groups debate a long-term strategy. The court’s one-sentence decision included no explanation and didn’t say whether the justices would consider the case on its merits.

Hours later, federal officials said two DNA samples taken beyond the final barriers between Chicago-area waterways and the lake had tested positive for carp — including one in the lake’s Calumet Harbor. They insisted it was far from certain that carp have actually reached the lake, saying no live or dead fish had been spotted.

Barge and tug operators called for Michigan and four other states to drop their legal battle to close the locks and focus on negotiation. But Govs. Jennifer Granholm of Michigan and Jim Doyle of Wisconsin said the court fight would continue and requested a meeting between White House officials and the Great Lakes governors.

“We cannot allow carp into the Great Lakes. It will destroy our Great Lakes fisheries, the economy,” Granholm said. “It is urgent.”

Last week, the Army Corps of Engineers said additional carp DNA — but no live fish — had been found in three different spots along the Chicago River within a mile of where it flows into Lake Michigan.

Michigan, joined by Minnesota, New York, Pennsylvania, Ohio, Wisconsin and the Canadian province of Ontario, asked the high court to order the locks closed as a stopgap measure while considering a permanent separation between Lake Michigan and the Mississippi basin.

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