Alaskans will vote on a ballot measure today that is being framed as a choice between salmon and mining and is portrayed as striking at the heart of what it means to be Alaskan. Frying Pan Lake, above, could end up being harmed by mining waste, proponents of the measure say.

Homer, Alaska ? Salmon and gold mining. Both are, inarguably, very Alaskan.

But today, Alaskans will vote on a ballot measure that is being framed as a choice between the two industries and portrayed by both sides as striking at the heart of what it means to be Alaskan.

The initiative was drafted to block the proposed Pebble Mine, a massive operation that would extract gold, copper and molybdenum from the tundra surrounding Bristol Bay in southwest Alaska, one of the world’s most lucrative wild salmon fisheries. The measure would prohibit any new large metal mines from polluting salmon streams or drinking-water sources. Proponents acknowledge that they drafted the measure to block the Pebble Mine, which they say will poison two major streams where salmon come to spawn.

Opponents of the measure say state and federal laws already protect water quality and the mine will not harm salmon. They argue that the ballot measure could reach far beyond Pebble Mine, freezing the industry and forcing mines to close. Their lawn signs say “Pro-Mining, Pro-Alaska,” and radio spots refer to the initiative as “un-Alaskan.”

Opponents have made much of the fact that one of the major funders of the ballot initiative, the group Americans for Job Security, is based in Washington. Proponents of the measure respond that the companies developing the mine are foreign: the London-based multinational mining giant Anglo American and Canadian company Northern Dynasty Minerals.

In a state where even a roadside pizza joint advertises itself as “by Alaskans, for Alaskans,” the concept of being Alaskan is crucial.

People flocked to Alaska for gold in the late 1800s, building towns and the state’s railroad around mining. When the price of gold and other metals stagnated after World War II, mining declined sharply and the state turned its attention to oil.

Alaska still boasts five major metal mines, and with high gold and copper prices today, many see mining as the state’s industry of the future, especially for Alaska Native communities that are struggling economically.

The fishing industry is the state’s largest private employer, with commercial, sport and subsistence fishing also central to the state’s identity and culture. Bristol Bay is Alaska’s most valuable salmon fishery, with 31 million salmon worth $108 million caught there in 2007. The salmon industry began to have difficulties in the 1980s because of competition from fish farms, but it is enjoying a resurgence today, thanks to renewed interest in wild salmon.

“Bristol Bay is part and parcel of the world obsession with wild salmon,” said Art Hackney, president of Alaskans for Clean Water, which drafted the ballot measure.

Pebble Partnership chief executive John Shively said the mine will not be developed if the company is not sure it can proceed without hurting salmon. “Obviously none of us want to destroy the fisheries,” he said, adding: “Fisheries probably provide more jobs, but mining is year-round jobs with higher incomes.”

Gloria Chythlook-Sifsof, a third-generation Bristol Bay commercial fisherman, said she thinks the mine will harm her industry even if it does not pollute the water.

“Even the tiniest hint that this fish isn’t safe is detrimental to the price of my fish,” said Chythlook-Sifsof. “If people think the fish could be contaminated, they won’t buy it. The timing of this couldn’t be worse, just as we are trying to salvage our industry.”