The conditions we are seeing out there are normally what we would see in late August. We are a month ahead in terms of temperatures. High temperatures harm returning fish by sapping their spawning strength and making it easier for disease to spread through the population. Heinith predicts that by September, the flow at Lower Granite Dam near Lewiston will be less than half of target flows to make sure the river is hospitable for migrating salmon. Stearns said it's not clear if there will be enough water in the Snake system to cool the river for returning adults in late August and September.
Northwest tribes advocate saving water for the fall to support the large tribal and sport fishery.
Heinith and Stearns predicted the region would see a decrease in salmon returns in three and four years, when this year's fish return to spawn.