NMFS has received new evidence of steelhead (anadromous Oncorhynchus mykiss) presence in two locations and spawning in one location south of the current range of the listed southern California steelhead Evolutionarily Significant Unit (ESU) which is currently Malibu Creek. Based upon this new information, and the possibility that anadromous O. mykiss may occur in other streams south of Malibu Creek if hydrologic and other habitat conditions are favorable, NMFS is now issuing a final rule under the Endangered Species Act (ESA) that redefines the geographic range of the listed anadromous O. mykiss population to include all steelhead and their progeny that occur in coastal river basins from the Santa Maria River (inclusive) to the U.S. - Mexico Border. NMFS has reassessed the status of anadromous O. mykiss throughout its redefined range in Southern California and concludes that the listed population continues to be endangered. Within the redefined geographic range of O. mykiss, only anadromous, naturally spawned populations, and their progeny, which reside below naturally occurring and man-made impassable barriers (e.g., impassable waterfalls and dams) are listed.