In Santa Paula Creek, a tributary to the Santa Clara River, Ventura County, California, opportunities for expression of the anadromous life history are restricted by migration barriers preventing the upstream return of adult steelhead. A residual population of O. mykiss now persists in suitable stream habitat above the Harvey Diversion (Stoecker and Kelley 2005). Restoring the migratory component of O. mykiss within the watershed has been identified as a priority management goal. O. mykiss in Santa Paula Creek and key tributaries; 2) determine key habitat characteristics of stream reaches occupied by O. mykiss; and 3) determine the relative abundance and age class structure of O. mykiss.

This report describes the methods and results of work completed to date, consisting of a reconnaissance-level field effort conducted in May 2007 and a more detailed population assessment of O. mykiss during November 2007. Results from these field efforts provide baseline information on O. mykiss distribution, habitat, and abundance in the Santa Paula Creek watershed under conditions which do not allow anadromy.