Fish Bulletin 180 California Coastal Salmonid Population Monitoring: Strategy, Design and Methods

California’s salmon and steelhead populations have experienced marked declines leading to listing of almost all of California’s anadromous salmonids under the California Endangered Species Act (CESA) and Federal Endangered Species Act (ESA). Both CESA and ESA listings require recovery plans that call for monitoring to provide some measure of progress toward recovery. In addition, there are related monitoring needs for other management activities such as hatchery operations and fisheries management.

This California Coastal Salmonid Monitoring Plan (CMP) has been developed to meet these monitoring needs, describing the overall strategy, design, and methods used in monitoring salmonid populations. Implementation details of the plan are described in Shaffer (in prep.). The CMP uses the Viable Salmonid Population concept as the framework for plan development. The VSP conceptual framework assesses salmonid viability in terms of four key population characteristics: abundance, productivity, spatial structure, and diversity. High abundance buffers a population against both ‘normal’ and catastrophic variation due to environmental conditions and loss due to anthropogenic factors. High productivity will lead to more certain replacement when populations are placed under either natural or anthropogenic stress. Wide spatial structure reduces extinction risk due to catastrophic events and provides pathways for recolonization. Diversity in life history traits (e.g., time of spawning, juvenile life history, adult fish size, age structure, degree of anadromy, etc.) provides resilience against extinction risk from changing conditions.