Designating Experimental Populations under the Endangered Species Act: Section 10(j)

Species are protected under the U.S. Endangered Species Act (ESA) because their numbers have declined to such an extent that they are in danger of becoming extinct. At such low numbers, many species often no longer occupy their historical habitats. Reintroducing a species into its historical range often is critical for its recovery.

The ESA provides an important tool to facilitate the reintroduction of threatened and endangered species, such as salmon. Section 10(j) of the ESA provides NOAA Fisheries and the U.S. Fish & Wildlife Service (collectively referred to as the Services) authority to designate populations of listed species as “experimental.” This designation allows the Services to reestablish self-sustaining populations in regions that are outside the species’ current range when doing so fosters its conservation and recovery.

An experimental population is a geographically-described group that is isolated from other existing populations of the species. Individuals in the experimental population are classified as threatened, not endangered, under the ESA. This designation provides flexibility in managing the reintroduced population. It allows the Services to reduce the legal protections required by the ESA, protecting individuals, municipalities, and others who may accidentally harm the fish while engaged in otherwise lawful activities.

When designating a population as experimental, additional classifications must be made. The Services must determine whether the population is “essential” to the survival of the species (i.e., the species will go extinct without the reintroduction of this population) or “non-essential” (i.e., the reintroduced population will contribute to restoring the species, but its recovery can be achieved without the population). To date, all of NOAA Fisheries' ESA 10(j) designations of Pacific salmon and steelhead populations have been classified as non-essential. Additionally, protective regulations, issued under section 4(d) of the ESA, often accompany a 10(j) designation. 

Designating experimental populations furthers conservation of at-risk species. It is an ESA tool that supports several conservation and societal goals. It allows the Services to advance recovery objectives by re-establishing self-sustaining populations, while simultaneously protecting private landowners, tribes, and local, state, and federal governments from ESA liabilities while they work to develop long-term conservation measures for the species. 

In 2016, NOAA Fisheries issued regulations to guide the development of future ESA 10(j) designations.

NOAA Fisheries' Current Reintroductions

West Coast Region

Okanogan River, Washington: Experimental Population Designation for Upper Columbia River spring-run Chinook

Upper Deschutes River, Oregon: Experimental Population Designation for Middle Columbia River steelhead

San Joaquin River, California: Experimental Population Designation for Central Valley spring-run Chinook

NOAA Fisheries' Proposed Reintroductions

West Coast Region

Upper Yuba River, California: Experimental Population Designation for Central Valley spring-run Chinook