If you spent a little more time researching this subject, instead of flapping your gums, you might just be half as smart as you think you are.
Notice that they don't mention over harvest as a factor.
And don't forget about where all those crab went, or do out migrating fish like dead zones?

http://wdfw.wa.gov/conservation/fisheries/steelhead/faq.html

Loss of functional habitat – particularly freshwater habitat – is generally believed to present the greatest risk to the state’s wild steelhead populations. In its ESA listing for Puget Sound steelhead, NOAA-Fisheries concluded “habitat is the principal factor limiting the viability of the Puget Sound steelhead DPS (distinct population segment) into the foreseeable future.”

In Puget Sound and other waters around the state, scientists note that water diversions for agriculture, flood control, residential use and hydropower have all reduced the amount of freshwater habitat used by naturally spawning steelhead. Forestry, mining and industrial development have also reduced or degraded habitat.

Steelhead are more vulnerable to these changes, because they spend more time in freshwater than other anadromous species. Unlike salmon, they often spend more than one year in freshwater and spawn in multiple years, depositing their eggs farther up rivers and streams. In the ocean, they also tend to school higher in the water column, making them more vulnerable to climate change or surface temperature changes.

WDFW has limited authority over land-use decisions, but does administer the Hydraulic Project Approval program, which regulates activities on and near state waters that could affect fish life. The department also coordinates habitat-restoration projects conducted by local governments, Regional Fisheries Enhancement Groups and other organizations. The statewide steelhead management plan directs WDFW to emphasize steelhead conservation in all of these programs.