How were fish affected by the eruption?
Before the 1980 eruption, the lakes and streams of the Mount St. Helens area supported about 26 fish species, including anadromous species that spawned in freshwater and migrated to the Pacific Ocean. Many of the rivers were well known for their spectacular runs of coastal rainbow trout (also known as steelhead when migratory) (Oncorhynchus mykiss iredeus), coho salmon (O. kisutch), and chinook salmon (O. tshawytscha), all of which had important recreational and aesthetic value. The high mountain lakes were historically fishless because fish could not reach them, but beginning in the early 1900s, these lakes were stocked regularly with fish. The 1980 eruption devastated some water bodies with fish and hardly changed others. Thus fish survival and recovery had very different patterns in the various bodies of water across the disturbance zones.
