NEW ORLEANS — Environmentalists, recreational fishermen and people who make their living on the Gulf of Mexico are hailing a federal judge’s ruling that could mean $18 billion in additional fines for BP over the nation’s worst offshore oil spill.

Lisa Smith cheered and gave an emphatic “yes” Thursday when she heard about the decision as she fished off a beach bridge in Florida.

“BP should have to pay. They’ve done a lot of damage,” Smith said.

In the town of Lafitte, La., David Robin said he hopes the oil company pays dearly, money that would not only mitigate damage from the spill, but also help restore Louisiana wetlands lost to erosion that experts blame in part on coastal oil and gas activity.