JUNEAU, Alaska -

A government report indicates a large-scale copper and gold mine in Alaska's Bristol Bay region could have devastating effects on the world's largest sockeye salmon fishery.

The U.S. Environmental Protection Agency released its final report Wednesday on the potential impacts of mining in the Bristol Bay region.

The report's findings are similar to those of an earlier draft. It concludes that depending on the size of the mine, up to 94 miles of streams would be destroyed by the mine's footprint, including up to 22 miles of streams known to provide salmon spawning and rearing habitat. Up to 5,350 acres of wetlands, ponds and lakes also would be lost.

In a Wednesday statement responding to the EPA report, Sen. Mark Begich says he will spend the next few days reviewing its findings.

“I have always said I will let science be my guide, and my decision whether to support the Pebble project will be based on this report,” Begich said. “The stakes are high for Alaska -- I have heard from thousands of Alaskans on this issue -- and that is why I will be thoroughly reviewing the final watershed assessment and continuing to rely on science for any final decision.”

A statement from Jason Metrokin, the president and CEO of Pebble Mine opponent Bristol Bay Native Corp., hailed Alaska Natives' role in calling for the EPA's review, while calling for the agency to take action against the proposed project.

“From the very beginning, EPA was in Bristol Bay because our federally recognized tribes and Native organizations, including BBNC, asked them to be," Metrokin said. "With today’s release, science has weighed-in: Bristol Bay, its existing jobs and way of life could be irreparably damaged by a large-scale mine that is the size and scope of the Pebble project -- and therefore, our fish, our people and our cultures must be protected."

The EPA has said its goal was to get the science right but The Pebble Partnership's CEO John Shively says he thinks the assessment wasn't scientific at all.

"I think from the beginning it's been a political based document," Shively said. "They really haven't done the kind of work that we and the state of Alaska and others have asked them to do."

Shively thinks the EPA didn't find the true affects mining would have on salmon, instead it replace it with affects mining would have on streams. Opponents of the pebble mine, like Trout Unlimited Consultant Rick Halford, say the EPA's assessment falls short on estimating the potential impact.

"If anything they probably under estimate the potential threat because the biggest proposal they talk about is just a little more than half the size of the deposit," Halford said. "The EPA is based on their lower projections and the lowest one probably doesn't even reflect the cost of building the infrastructure."

The EPA says its next step will be a regulatory action but no time table has been set for that decision.

Channel 2's Chris Klint and Garrett Turner contributed information to this story.