Endangered Species Law & Policy

On November 21, 2025, the U.S. Fish & Wildlife Service and National Marine Fisheries Service (collectively, the Services) published several proposed rules to revise their regulations implementing certain provisions of the Endangered Species Act (ESA). To a substantial extent, the Services are proposing to return to the regulations put in place by the first Trump administration in its prior rulemakings and thereby undo the changes put in place by the Biden administration in its prior rulemakings. This is one in a series of blog posts that will briefly describe each proposed rule. The notice states the Services will accept comments on the proposed rules until December 22, 2025. A number of stakeholders have asked the Services to extend the comment deadline. As of this time, the Services have not done so.

In one of the proposed rules, the Services propose to revise portions of their regulations implementing the listing and critical habitat provisions in section 4 of the ESA. The listing provisions in section 4 provide a process whereby any person may petition the Secretary of Commerce or the Interior to list a species as threatened or endangered under the ESA. The process includes timelines to make certain determinations including a 90-day period to determine whether listing may be warranted and a 12-month period to determine whether listing is not warranted, is warranted, or is warranted but precluded by other higher priority actions. The critical habitat provisions in section 4 contemplate designation of critical habitat concurrent with listing and describe the factors the Services must consider when determining whether to designate an area as critical habitat.

With respect to the listing provisions, the Services propose two substantive changes to return to their 2019 regulations. First, the Services propose to amend the provision describing what is meant by the term “foreseeable future,” which is included in the statutory definition of a “threatened species.” The change is intended to emphasize that the scope “is bounded by what is foreseeable based on the best scientific and commercial data available.” Second, the Services propose to amend the provision relating to delisting of species. The change is intended “to better clarify the circumstances in which species should be delisted.”

With respect to the critical habitat provisions, the Services also propose two substantive changes to return to the 2019 regulations. First, the Services propose to amend the provision describing the circumstances in which they may find it is not prudent to designate critical habitat. This change is intended to add back into the regulations the notion that it may not be prudent to designate critical habitat where “threats to a species' habitat that lead to endangered-species or threatened-species status stem solely from causes that cannot be addressed by management actions identified in a section 7(a)(2) consultation.” Second, the Services propose to amend the provision with respect to designation of areas that are not occupied by a species as critical habitat for that species. The change is intended to require the Services to “only consider unoccupied areas to be essential where a critical habitat designation limited to geographical areas occupied would be inadequate to ensure the conservation of the species.”