Measuring Biological Sustainability via a Decision Support System: Experiences with Oregon Coast Coho Salmon

Conservation status of salmon is determined by a wide variety of factors, and comprehensive assessment requires integrating a complex set of information. As part of Endangered Species Act recovery planning for the Oregon Coast Coho Salmon Evolutionarily Significant Unit (ESU), the Oregon and Northern California Coasts Technical Recovery Team developed a formal decision support system incorporating a suite of biological recovery criteria. These criteria include information on fish abundance, productivity, diversity, distribution, and habitat at a variety of geographic scales: watersheds, populations, biogeographic strata, and the entire ESU. The decision support system evaluates low-level criteria and combines these through a logic network to evaluate biological persistence and sustainability at population, stratum, and ESU scales. Mapping of results provides a tool that allows decision makers to visualize how local conditions contribute to the overall assessment. The system has been used by both state and federal agencies in status assessments for subsequent endangered species listing decisions, with sometimes disparate interpretations of the required input data, definitions of individual criteria, and the ultimate meaning of the integrated measure of ESU status. We examine the sources of these disagreements, and discuss what aspects of the approach worked well, what didn't work, and suggest future improvements.