ISHI PISHI FALLS, SISKIYOU COUNTY, Calif. — Carrying a pair of 20-foot wooden poles with a net strung between them, Ron Reed shimmied above the Klamath River across wooden boards perched between slippery boulders. He paused and stared into the white foam. With a lunge, Reed, a 60-year-old fisherman who belongs to the Karuk Tribe, thrust his dip net into the Klamath’s swirling current. His back and his ropey arms strained against the fir poles as he heaved up two Chinook salmon that thrashed and twisted inside the net. By the end of the morning, Reed and his son-in-law Asa Donahue caught seven …