Skip to main content

Endangered Species: Fish and Wildlife Service Uses Best Available Science to Make Listing Decisions, but Additional Guidance Needed for Critical Habitat Designations

GAO-03-803 Published: Aug 29, 2003. Publicly Released: Sep 29, 2003.
Jump To:
Skip to Highlights


Recent concerns about the U.S. Fish and Wildlife Service's (Service) endangered species listing and critical habitat decisions have focused on the role that "sound science" plays in the decision-making process--whether the Service bases its decisions on adequate scientific data and properly interprets those data. In this report, GAO assesses the extent to which (1) the Service's policies and practices ensure that listing and critical habitat decisions are based on the best available science and (2) external reviewers support the scientific data and conclusions that the Service used to make those decisions. In addition, GAO highlights the nature and extent that litigation is affecting the Service's ability to effectively manage its critical habitat program.

Skip to Recommendations


Recommendations for Executive Action

Agency Affected Recommendation Status
Department of the Interior Because the Service's critical habitat program faces serious challenges, the Secretary of the Interior should require the Service to provide clear strategic direction for the critical habitat program, within a specified time frame, by clarifying the role of critical habitat and how and when it should be designated, and recommending policy/guidance, regulatory, and/or legislative changes necessary to provide the greatest conservation benefit to threatened and endangered species in the most cost-effective manner.
Closed – Implemented
Since 2012, the Fish and Wildlife Service (Service), in collaboration with the National Marine Fisheries Service, has issued policy and guidance related to designating critical habitat for listed species and to clarify the role of critical habitat. For instance, in 2012, the Service published regulations that clarified practices for providing the public with the geographic coordinates from which critical habitat designation maps are generated. In 2016, the Services published three additional rules intended to clarify, interpret, and implement portions of the Endangered Species Act concerning, among other things, the procedures and criteria used for designating and revising critical habitat, such as revising the definition of "destruction or adverse modification of critical habitat."

Full Report

Office of Public Affairs


Endangered speciesStrategic planningWildlife conservationWildlife managementProgram evaluationSpeciesPeer reviewHabitatWildlifeLitigation