A rapids-loving, odd-looking native fish found locally in the Colorado River is now officially considered to be at a reduced risk of extinction.
The U.S. Fish and Wildlife Service on Friday said it has reclassified the humpback chub from endangered to threatened under the Endangered Species Act, thanks to significant progress made by conservation and recovery efforts of federal agencies, states, tribal entities and private partners.
“It’s a major milestone that we feel very proud of,” Kevin McAbee, acting director of the Upper Colorado River Endangered Fish Recovery Program, told The Daily Sentinel. “We believe that it demonstrates the collaborative conservation efforts that we’ve been undertaking with our partners over the last three-decades-plus are working. It’s really something that we’ve been working towards for many years and we’re just very excited about it.”
According to the agency, the fish was first documented in the Grand Canyon in the 1940s and the upper Colorado River Basin in the 1970s, and placed on the list of endangered species in 1967 due to impacts from changes in river habitats caused by large dams.
Feeding on insects, crustaceans and plants, the humpback chub can live 20 to 40 years, grow up to 19 inches long and produce up to 2,500 eggs per year. A warm-water species, it is uniquely adapted to live in the turbulent whitewater found in rivers’ rocky canyon areas, according to the Fish and Wildlife Service. Its namesake, fleshy lump behind its head evolved to make it harder to be eaten by predators, and large, curved fins let it stay in place in swift currents.
These traits have helped it survive in the Black Rocks area of the river in western Mesa County and in Westwater Canyon just across the Utah border, where the Fish and Wildlife Service says the most recent estimates indicate there are populations of 430 and 3,300 adults, respectively. The Westwater Canyon population has been growing and the Black Rocks numbers are stable, but a large number of juveniles may boost the Black Rocks population in the future.
Other stable populations exist at the Desolation/Gray canyons area on the Green River in Utah and Cataract Canyon on the Colorado River in Utah. The Grand Canyon is home to the largest number of fish, including an estimated 12,000 in a core area in the Little Colorado River and the Colorado River around their confluence.
Globally, the fish exists only in that handful of core population areas. Another population in Dinosaur National Monument appears to have died out. McAbee said the Westwater and Black Rocks populations combined are the largest population upstream of Lake Powell, making them the home of the largest combined population in the world of humpback chub outside of the Grand Canyon, and an important core population just downstream of Grand Junction.
“And so it’s really important and it’s really local to Grand Junction,” he said. “I feel like it’s important to recognize how culturally and historically important humpback chub were to the area, and how that population is growing and rebounding and how big a part of this reclassification that Westwater population and its increases were to the decision,” he said.
Two multi-stakeholder efforts, the Upper Colorado River program and Glen Canyon Dam Adaptive Management Program, have worked to try to help recover the species. In the Upper Colorado River, these efforts have included protecting river flows; managing and removing predatory, nonnative fish; and installing and operating fish passage structures where dams otherwise can impede fish travel.
Water-release measures involving upstream reservoirs have helped manage river flows to benefit the fish despite drought conditions that largely have prevailed over the last two decades. The Fish and Wildlife Service concluded that current river flows and temperatures are largely adequate despite climate change, so it doesn’t put the fish at immediate risk of extinction, which would mean it’s endangered. But the agency found that uncertainty about the possible severity of future water-supply declines poses a threat to the fish in the future, so it is likely to become endangered in the foreseeable future — the criteria for determining that it is threatened.
Another uncertainty surrounds the future of conservation efforts in the Upper Colorado River Basin because the recovery program there currently is scheduled to expire in 2023.
“However, commitment to continue the decades-long partnership is strong, as demonstrated by ongoing efforts to extend the partnership beyond 2023,” the Fish and Wildlife Service says in its final rule on the fish’s downlisting.
U.S. Rep. Joe Neguse, D-Lafayette, has introduced a bill that would extend by a year the life of programs that seek to protect endangered fish in the Upper Colorado and San Juan river basins. Other fish that are the focus of the program are the bonytail, razorback sucker and Colorado pikeminnow. The Fish and Wildlife Service also is considering downlisting the razorback sucker to threatened status.
A further challenge for the program that the Fish and Wildlife Service is monitoring is the status of its funding.
Federal hydropower revenue that has helped support the program is threatened because falling reservoir levels are jeopardizing hydropower generation.
Some conservationists oppose downlisting of the humpback chub and razorback sucker, based on concerns ranging from the adequacy of current population numbers to declining water volumes in rivers and impacts from nonnative fish. The states of Colorado, Utah and Arizona all support the downlisting of the humpback chub, along with a separate finalized Fish and Wildlife Service rule that will reduce regulatory requirements for state fish and wildlife agencies and other non-federal stakeholders when working to protect and recover the humpback chub.
That rule allows for some exemptions from a prohibition protecting the fish from “incidental take,” such as death or harm, occurring during activities such as creating refuge populations, moving fish to new waters, removing non-native fish species, and creating catch-and-release fishing opportunities outside of core population areas to boost public awareness about the humpback chub.