WASHINGTON — The U.S. Supreme Court has declined to intervene in a long-running legal challenge to the listing of the Alabama sturgeon as an endangered species.

In an order issued this morning without comment, the high court turned down the appeal of the Alabama-Tombigbee Rivers Coalition, an industry group opposed to the listing. The decision effectively upholds lower court rulings that federal officials acted properly in granting the sturgeon endangered species protection in 2000.

From a legal perspective, “it should be the end of the road, as far as I know,” said Jason Rylander, a staff attorney for Defenders of Wildlife, a Washington, D.C.-based environmental organization that supported the listing. Lawyers for the coalition, which includes Alabama Power Co. and the Alabama State Port Authority, could not immediately be reached for comment.

Once plentiful in the rivers that drain into Mobile Bay, the sturgeon, brassy orange and about 30 inches long, is now ranked among the nation’s rarest fish.