CHICAGO (CBS) — A federal appeals court has ruled that the Chicago shipping locks will not be closed in the interest of keeping the Asian carp out of the Great Lakes.

The 7th U.S. Circuit Court of Appeals in Chicago is the latest of several courts to turn down a plea from the states of Michigan, Minnesota, Ohio, Pennsylvania and Wisconsin, for an order that the locks be closed immediately so as to halt the carp’s northward march from the Mississippi River toward Lake Michigan.

U.S. District Judge Robert Dow in Chicago did likewise last December.

The states have a pending lawsuit against the U.S. Army Corps of Engineers and the Chicago water reclamation district that calls for permanently severing a century-old, man-made link between the Mississippi and Great Lakes drainage basins. They had sought a court order to close the locks, which could provide a pathway to Lake Michigan for the carp, while their suit works through the courts. With the appeals panel’s ruling, that prospect appears remote.

Significantly, however, the three-judge panel disagreed with Dow’s conclusion that the states appeared to have little chance of succeeding in their lawsuit. Dow had acknowledged a carp invasion could harm the Great Lakes but said the states hadn’t shown it was likely or imminent. He said flooding and economic damage from closing the locks would do more damage to Chicago-area businesses and homeowners than “the more remote harm associated with the possibility” of Asian carp becoming established in the lakes.

In their opinion, Judges Daniel Manion, Diane Wood and Ann Claire Williams said they were “less sanguine about the prospects of keeping the carp at bay.”

“In our view, the plaintiffs presented enough evidence at this preliminary stage of the case to establish a good or perhaps even a substantial likelihood of harm — that is, a non-trivial chance that the carp will invade Lake Michigan in numbers great enough to constitute a public nuisance,” the judges said.

The Obama administration has pledged more than $120 million for a wide-ranging strategy to keep the carp out of the lakes. Because of those efforts, requiring immediate actions such as lock closure “would only get in the way,” the judges said. “We stress, however, that if the agencies slip into somnolence or if the record reveals new information at the permanent injunction stage, this conclusion can be revisited.”

The five states could take their request to the full 7th Circuit court or try again before the Supreme Court. No decision has been made, said Joy Yearout, spokeswoman for Michigan Attorney General Bill Schuette.

Meanwhile, the Great Lakes remain untouched by the Asian carp menace. Testing earlier this year found carp DNA in Lake Calumet, but four days of intensive monitoring earlier this month turned up no trace of the voracious fish.

(TM and © Copyright 2011 CBS Radio Inc. and its relevant subsidiaries. CBS Radio and EYE Logo TM and Copyright 2011 CBS Broadcasting Inc. Used under license. All Rights Reserved. This material may not be published, broadcast, rewritten or redistributed. The Associated Press contributed to this report.)

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