Framework for Assessing Viability of Threatened and Endangered Chinook Salmon and Steelhead in the Sacramento–San Joaquin Basin

By Steven Lindley, Robert S. Schick, Ethan A. Mora, Peter B. Adams, James J. Anderson, Sheila Greene, Dennis R. McEwan, R. B. MacFarlane, John G. Williams. 2007

86 citations recorded by the source corpus.

Protected evolutionarily significant units (ESUs) of salmonids require objective and measurable criteria for guiding their recovery. In this report, we develop a method for assessing population viability and two ways to integrate these population-level assessments into an assessment of ESU viability. Population viability is assessed with quantitative extinction models or criteria relating to population size, population growth rate, the occurrence of catastrophic declines, and the degree of hatchery influence. ESU viability is assessed by examining the number and distribution of viable populations across the landscape and their proximity to sources of catastrophic disturbance. Central Valley spring-run and winter-run Chinook salmon ESUs are not currently viable, according to the criteria-based assessment. In both ESUs, extant populations may be at low risk of extinction, but these populations represent a small portion of the historical ESUs, and are vulnerable to catastrophic disturbance. The winter-run Chinook salmon ESU, in the extreme case, is represented by a single population that spawns outside of its historical spawning range. We are unable to assess the status of the Central Valley

Subfields: Ecology, Nature and Landscape Conservation, Water Science and Technology

View Paper: https://www.semanticscholar.org/paper/22ea9bdda0bd3fced202819a5007180d3b7d60da