The commercial fishing season on the Yukon River—among the most prolific salmon rivers on earth—usually opens June 15, but last year it didn’t. Alaska’s Department of Fish and Game monitors the river using sonar and test nets and opens the season only after enough fish have passed upriver to their spawning grounds to maintain the population. Although a better-than-average run had been predicted for 2008, by June 15 virtually no salmon had appeared. Or so said Fish and Game. But the 856 Yupik Eskimos living in Emmonak, the village at the heart of Alaska’s Yukon Delta, didn’t believe it.…