Opponents of the drilling declared victory on Thursday after the government acknowledged that permits to allow seismic blasting in the ocean — the first step toward locating oil deposits for drilling — will expire next month and not be renewed.

Nine state attorneys general and several conservation groups filed a federal lawsuit early last year to block seismic blasting, arguing it could harm endangered whales and other marine animals. The court battle dragged out so slowly that, in the meantime, time ran out on the permits.

Donna Wieting, director of the National Marine Fisheries Service, a division of the National Oceanic and Atmospheric Administration, said Thursday that her agency “has no authority to extend the terms of those [permits] upon their expiration. Further, NMFS has no basis for reissuing or renewing these [permits].” The five companies that were granted permits would have to restart the months-long process leading to approval or denial, Wieting said.

Also on Thursday, U.S. District Judge Richard Gergel of South Carolina held a telephone conference with all parties of the lawsuit to determine how to move forward. The judge is expected to declare the case moot because the seismic mapping cannot occur without the permits, said Michael Jasny, who was on the call and is director of the Marine Mammal Protection Project at the Natural Resources Defense Council.

The attorneys and conservationists are focused on protecting the North Atlantic right whale, which is “one step from extinction,” the International Union for Conservation of Nature determined in July. Only about 250 adults remain, including 100 breeding females after collisions with ships, entanglements in fishing nets and underwater noise pollution, according to an assessment by the group.

“It’s most definitely a win. There’s no question,” Jasny said. “Given the broad bipartisan opposition that the threat of seismic blasting