[co-author: Noah DeWitt]

On July 7, 2021, the U.S. Fish and Wildlife Service (FWS) published a proposed rule in the Federal Register announcing the agency’s finding that the razorback sucker (Xyrauchen texanus) no longer warrants listing as an endangered species under the federal Endangered Species Act (ESA). As such, FWS has proposed to downlist the species to threatened status.

The razorback sucker is a freshwater fish measuring up to 3 feet long that gets its name from the bony ridge behind its head. The species is commonly found throughout the reservoirs, floodplains, and backwaters of the Colorado River and has a lifespan of up to 40 years. Once having a population of over 70,000 spanning the entire length of the Colorado River, the razorback’s numbers began to dwindle in the mid-1900s until it was estimated in 2000 that only 100 wild adults remained. FWS credits this decline largely to the introduction of nonnative sportfish into the species’ habitat and the installation of dams that altered the flow of the Colorado River.

As a result of these impacts, FWS listed the razorback sucker as endangered in 1991 and subsequently issued and implemented recovery plans for the species. These recovery plans included the establishment of a genetic refuge in Lake Mohave, stocking habitats with hatchery-produced razorback suckers, and measures to control the growth of nonnative fish species. In the proposed rule, FWS states that because of these efforts, the adult razorback sucker population is now “relatively stable between 4,000 and 5,000” individuals, and the species “is not currently at risk of extinction.” Therefore, FWS determined that the species no longer meets the ESA’s definition of an endangered species. However, due to the razorback sucker’s continued dependence on FWS’s efforts to support the species’ ongoing recovery, FWS found that the species does meet the definition of a threatened species under the ESA.

In addition to the razorback sucker’s proposed downlisting, FWS also proposes to promulgate a section 4(d) rule which would “prohibit all intentional take of the razorback sucker” while promoting actions that facilitate the species’ conservation and management. The proposed 4(d) rule provides exceptions to the intentional take prohibition for certain activities, including activities related to razorback sucker education, catch-and-release angling, and population restoration efforts.

The agency’s proposed rule and supporting documents are available at regulations.gov, under Docket Number FWS-R6-ES-2020-0057. The 60-day period for public comment on the proposed rule is currently set to end on September 7, 2021.