The federal panel that oversees commercial and subsistence fishing in Alaska is putting a hard limit on the number of chum salmon that are caught — and wasted — by commercial pollack trawlers. It is a long awaited — and controversial — decision by the North Pacific Fishery Management Council after years of outcry by tribes to address the factors that go into the disappearing runs of salmon that Alaska Native people have always relied on for survival. Although presented as a compromise, the bycatch limit is seen as a severe blow by commercial fishers, who say such restrictions could be catastrophic to the industry. The decision comes as the state also instituted severe regional restrictions on king salmon fishing because of low numbers. They are among the latest measures to address the big and complex ecological threats to what is historically the most productive salmon fishery in the world.