Endangered and Threatened Species: Listing of Several Evolutionary Significant Units (ESUs) of West Coast Steelhead

On August 9, 1996, NMFS completed a comprehensive status review of west coast steelhead (Oncorhynchus mykiss, or O. mykiss) populations in Washington, Oregon, Idaho, and California, and identified 15 Evolutionarily Significant Units (ESUs) within this range. NMFS is now issuing a final rule to list two ESUs as endangered and three ESUs as threatened under the Endangered Species Act (ESA). The endangered steelhead ESUs are located in California (Southern California) and Washington (Upper Columbia River). The threatened steelhead ESUs are located in California (Central California Coast and South-Central California Coast) and Idaho, Washington, and Oregon (Snake River Basin). For the endangered ESUs, section 9(a) prohibitions will be effective 60 days from the publication of this final rule. For the threatened ESUs, NMFS will issue shortly protective regulations under section 4(d) of the ESA, which will apply section 9(a) prohibitions with certain exceptions. NMFS has examined the relationship between hatchery and natural populations of steelhead in these ESUs, and has assessed whether any hatchery populations are essential for their recovery. Only the Wells Hatchery stock in the Upper Columbia River ESU is essential for recovery and included in this listing. Aside from the Wells Hatchery stock, only naturally spawned populations of steelhead (and their progeny) residing below long-term, naturally and man-made impassable barriers (i.e., dams) are listed in all five ESUs identified as threatened or endangered. At this time, NMFS is listing only anadromous life forms of O. mykiss.