"A salmon population is considered to be viable if it is expected to persist for at least 100 years with a high probability. Population-based criteria necessary for viable salmonid populations (VSPs) include specific conditions of 1) abundance, 2) productivity, 3) diversity, and 4) spatial structure. The Puget Sound Technical Recovery Team (PSTRT) developed viability criteria for the Lake Ozette sockeye salmon (Oncorhynchus nerka) evolutionarily significant unit (ESU), which is comprised of a single population."--Executive summary.

National Marine Fisheries Service (NMFS)