But NMFS biologist Peter Dygert said the agency changed its policy because it became convinced the harvest agreement's sliding scale provides more protection for chinook than the flat 9 percent harvest allowed in the past. The sliding scale would have allowed harvests larger than 9 percent only three times in the last 20 years, Dygert said. Some years, it would have meant a harvest of only 7 percent. Whether the intentional kill is 15 percent or 9 percent matters little whendams kill 40 percent of the adult spring chinook, said Bill Tweit, who oversees Columbia River policies for the Washington Department of Fish and Wildlife. This year's big catch may help keep the region's interest in salmon restoration, said Dygert.
Biologists credit a number of factors for setting up the big run.
No one can say whether those conditions will ever be matched again. Most of this year's adults are the progeny of the plentiful chinook that spawned in 1997. At the same time, ocean conditions, which had been sour for many years, turned favorable as currents shifted. That increased the food supply for salmon that spent their growing years off the coast of Washington, Oregon and British Columbia. Looking ahead, things don't look nearly so rosy.