ANCHORAGE — A 2008 lease sale in the Chukchi Sea off Alaska’s northwest coast remains legally flawed and should be cancelled, Alaska Native and environmental groups say in a court filing.

Earthjustice attorney Erik Grafe said Thursday the sale does did not follow federal environmental law despite Interior Secretary Ken Salazar’s conclusion last month that shortcomings identified by a federal judge had been addressed. Top federal government scientists acknowledge gaps in what is known of basic features of the Arctic Ocean, Grafe said, such as areas important to bowhead and beluga whales, walrus, seals, birds and fish.

“There are huge gaps in information that we think preclude an ability to analyze the facts and choose alternatives and manage any kind of lease sale manage or oil and gas activity up in the Arctic,” Grafe said.

An Interior spokeswoman said the department would have no comment.

The Minerals Management Service conducted the Chukchi sale during the waning days of the Bush administration, putting up nearly 46,000 square miles — an area larger than Ohio — in the waters off Alaska’s northwest coast. About 4,312 square miles were sold. A subsidiary of Royal Dutch Shell spent $2.1 billion and hopes to drill during the open water season next summer.

The 15 groups sued before the sale, claiming federal regulators had ignored environmental law requirements.

U.S. District Court Judge Ralph Beistline ruled in part that regulators failed to determine whether information they acknowledged was missing before the sale was relevant or essential, or whether the cost of obtaining that information was exorbitant.

Salazar on Oct. 3 said the replacement for the Minerals Management Service, the new Bureau of Ocean Energy Management, had met the judge’s concerns with supplemental environmental work. That included an analysis of potential effects of natural gas development, the relevance of the missing information, and the environmental impacts of a hypothetical large oil spill.

By affirming the 2008 lease sale, Grafe said, the Obama administration has adopted the mistakes of the previous administration.

Interior officials contend that not a single piece of missing information is critical to make a reasoned choice among lease sale alternatives, Grafe said in his brief, such as how disturbances from lease sale activity may affect bowhead whales, the lynchpin of Inupiat Eskimo subsistence culture. They withheld sales from nearshore areas to accommodate spring bowhead migration, Grafe said, but acknowledge they know less about bowhead aggregation in summer and fall.

“That’s the kind of information that’s critical at this stage, that kind of spatial information, what’s important habitat for these animals” he said.

BOEM uses boilerplate explanations used to justify that information is not essential, such as that information can be obtained later in the offshore development process, or that other environmental laws will preclude adverse effects, Grafe said in his brief. The groups also said the government has refused to analyze and consider the climate change effects of burning oil and gas produced by the lease sale.

Mike LeVine, an attorney for Oceana, one of the plaintiffs, said by phone from Juneau that agency officials have been contradictory. In announcing a new five-year offshore leasing plan last week, Interior officials said they would hold Arctic Ocean sales late in the five-year time frame to allow for scientific evaluations in the “frontier” drilling area.

“On the other hand, it’s gone out and said it doesn’t need any more information to affirm its decision to sell the leases from 2008,” LeVine said. “It’s inconsistent.”