Silvery coho salmon are as much a part of Washington state as its flag. The fish has a sacred place in the diets and rituals of the state's indigenous peoples, beckons to tourists who flock to watch its migration runs, and helps to sustain a multimillion dollar Pacific Northwest fishing industry.So watching the species die in agony is distressing: adults have been seen thrashing in shallow fresh waters, males appear disoriented as they swim, and females are often rolled on their backs, their insides still plump with tiny red eggs that will never hatch.