ANCHORAGE, Alaska (Reuters) - Nearly 2 million acres of U.S. federal land in southwestern Alaska best known for its rich salmon runs and abundant wildlife will be available for development under a new management plan released on Friday by the U.S. Bureau of Land Management.

The management plan covers up to 1.9 million acres of mostly flat terrain near Bristol Bay and adjacent Goodnews Bay that, up to now, had been off-limits to development.

Mining giant Anglo American and Vancouver-based Northern Dynasty Minerals Ltd are proposing to build a huge copper, gold and molybdenum mine -- the Pebble project -- on state land in the region.

The Pebble project has drawn fierce opposition for the potential damage it may cause to Bristol Bay salmon runs, the world’s largest. At the same time, the Bush administration and Alaska state government are advocating offshore oil and gas development near Bristol Bay.

Gary Reimer, manager for the BLM’s Anchorage district, said the new plan establishes a framework for permits and regulations should any development be proposed, but that it is unlikely that the BLM land in the management plan will be the site of any major new development.

“Do we believe this would lead to anything of any size? No,” Reimer said. “Of the 1.9 million (acre) area, there is very little mineral potential.”

Environmentalists disagree and characterize the new plan as part of a strategy to open up the entire area to mining and drilling. Fishing and Native groups have also fought the new plan since it was proposed in draft form a year ago.

Jeremiah Millen, field representative for the Alaska Wilderness League, disputed the idea that the BLM land will not attract developers, saying that the agency used outdated economic data in its analysis and underestimated the lure of the minerals and petroleum resources.

“You can guarantee that, by opening an additional almost 2 million acres out there, there will be a rush to development,” said Millen, noting that the plan does not provide specific protections to salmon habitat and fishing-dependent communities.

When work on the land-management plan started in 2004, the area under study covered 3.6 million acres, but some of the land was transferred into state ownership or into the hands of various Alaska Native corporations, according to the BLM.

More such conveyances are expected and could whittle the total area of BLM-controlled land in the region to 1.5 million acres, the agency said.