Habitat loss and modification are believed to be the major factors determining the current status of salmonid populations. Conservation and recovery of Pacific Northwest salmon and steelhead depend on having diverse habitats with connections among those habitats. The salmonid lifecycle involves adults maturing in the ocean, migrating back to their home streams and spawning, embryos incubating, fry emerging, juveniles growing, and smolts migrating to the estuary to acclimate to saltwater and moving out into the ocean. Each phase may require use of and access to distinct habitats. Loss of habitat reduces the diversity in salmon and steelhead life histories, which influences the ability of these fish to adapt to natural and man-made change.

Salmon need freshwater habitat that includes:

• cool, clean water
• appropriate water depth, quantity and flow velocities
• upland and riparian (stream bank) vegetation to stabilize soil and provide shade
• clean gravel for spawning and egg-rearing
• large woody debris to provide resting and hiding places
• adequate food
• varied channel forms.