View Population Data

The Big Picture

Created by Megan Webb of The Nature Conservancy, California
Population data courtesy of CDFW, NOAA Fisheries, and other federal, state, and local agencies, watershed groups, and conservation organizations.
Evolutionarily Significant Units (ESU) are defined by NOAA Fisheries under their Endangered Species Act (ESA) status reviews. They are defined as a population that is substantially reproductively isolated from conspecific populations and represents an important component in the evolutionary legacy of the species.