5-Year Review: Summary and Evaluation of South-Central California Coast Steelhead Distinct Population Segment

The South-Central California Coast Distinct Population Segment (DPS) is listed as threatened and is comprised of a suite of steelhead populations (Oncorhynchus mykiss) that inhabit coastal stream networks from the Pajaro River south to, but not including the Santa Maria River. Freshwater-resident (non-anadromous) O. mykiss, commonly known as rainbow trout, also occur in the same geographic region, frequently co-occurring in the same river systems as the anadromous form. Clemento et al. (2009) found that O. mykiss above and below impassable dams within the South-Central Coast DPS tended to be each other’s closest relatives, suggesting that each steelhead DPS is simply the anadromous component of a corresponding Evolutionarily Significant Unit (ESU; Waples 1991) comprising both anadromous and resident O. mykiss. Anadromous and/or freshwater forms of the species also occur in some basins south of the U.S. border, on the Baja California Peninsula (Ruiz-Capos and Pister 1995). 2016 Submitted Public Domain 1861