Coho and chum live for 4–6 years. Both species typically spawn late September to December and die within days after spawning. Cutthroat trout can spawn multiple times during their lifecycle. During spawning season, residents may expect to see coho and chum migrating up stream systems on route to their natal spawning grounds. Within their spawning grounds, coho and chum make little mounds of gravel called "redds," where fertilized eggs may develop and be protected over the winter. In spring, salmon fry emerge from the gravel.
During spawning season, the carcasses of spawned coho and chum may be found downstream of redds and/or along stream banks. The carcasses are an important part of the ecosystem serving as food for other animals and a source of nutrients for streamside vegetation.
Water quality, in-stream material and streamside vegetation are all important parts of salmon habitat. Salmon require clean, cold water and a variety of in-stream gravel, rock and wood debris (e.g. twigs, small logs and beaver dams) to create pools and riffles so they can rest and spawn. Native vegetation growing along the streambank is also important to the life of salmon, providing shade and food.