A lot of efforts to protect endangered species get framed as jobs vs. the environment. With salmon, that's not the case. Instead it's a matter of different sectors of the economy at odds with each other. (Those sectors, as it happens, include traditional Native America n economies and cultural practices.) And for a long, long time, salmon - and the tribes - have been on the short end of the stick.
Salmon are anadromous fish, which means their life history requires an entire freshwater watershed, in addition to time spent in the ocean maturing to adulthood. Adults return to their birthplace in the headwaters to spawn, where the young hatch. They make their way downstream, undergoing a major physiological change to transition from fresh water to salt water in a life stage known as smolt, spent in estuaries. They are vulnerable to environmental damage (logging, dreding, filling, dams, toxins, siltation) at any point in their life history, anywhere in the watershed.
And in larger rivers like the Columbia (or the Sacramento or the Klamath) dams like Bonneville and Grand Coulee caused precipitous drops in salmon spawning runs. The good news is that there were more chinook salmon pass upstream at Bonneville in this year's run than there have been since the Army Corps of Engineers built it in the 1930s.