The purpose of this bulletin is to present the historical and current status of steelhead in coastal California streams south of San Francisco Bay. Habitat conditions, in conjunction with population information, are used as the means for making assessments. When possible, factors that regulate population size are identified, both on an interannual basis and with regard to long-term population trends. In addition, existing biological information is inventoried for future use in ecologically characterizing these populations. Finally, contemporary theories in both basic and salmonid ecology are integrated with the results to develop future research ideas.