Feds downlist one of Grand Canyon's native fish

The freshwater fish, which is native to the Colorado River and the Grand Canyon, was first listed in 1991 after dams on the river and other waterways in the Colorado River Basin fractured its habitat and created conditions that hampered its ability to reproduce. Non-native fish in the river also contributed to losses to the species.

The sucker is the second Canyon fish downlisted from endangered to threatened. The Fish and Wildlife Service reclassified the humpback chub in October 2021.

Conservation groups say the decision to downlist the sucker ignores the threats that remain.

“The razorback sucker’s outlook is no better today than when the fish was originally protected under the Endangered Species Act in 1991, so this move makes no sense,” said Taylor McKinnon, Southwest director at the Center for Biological Diversity. “It’s still in danger of extinction throughout its range, which should preclude this downlisting.”

The Fish and Wildlife Service said a series of conservation measures, such as stocking fish from hatcheries, non-native fish control and habitat restoration have helped stabilize populations in rivers around the Colorado River basin. The species is now found in eight populations, the agency said. The largest is in the Green River on the upper Colorado, where numbers have grown from about 100 in the late 1990s to about 36,000 today.

The fish species still faces threats to its survival, the agency said, including changes in river flows and habitat, changes in water quality, drought and non-native species.

The razorback sucker is one of eight fish native to the Grand Canyon. Of those, three — the Colorado pikeminnow, roundtail chub and bonytail — are extinct. The construction of Glen Canyon Dam altered the flow of the Colorado River and changed the water temperature, forcing wildlife agencies to step in and help preserve species.

Scientists worked for years to help the humpback chub, which was near extinction at one point. The species' numbers in the main Colorado and the Little Colorado rivers have grown, but only because of human intervention, scientists say.

The razorback has a distinctive bony keel behind its head. It's the largest of its type in the Colorado River and can grow up to 3 feet long and weigh 10 pounds or more. Their mouths allow them to feed on insects and plants from a river's channel. Beyond Arizona, they are found in California, Colorado, Nevada, New Mexico and Utah, and were once found in Wyoming and the Mexican states of Baja and Sonora.

But conservation groups say the razorback sucker populations are not stable enough to warrant downlisting.

“The razorback sucker would cease to exist without the dumping of thousands of hatchery-raised fish into rivers each year,” McKinnon said. “Hatchery and habitat restoration programs are bass feeding programs that don’t tackle the underlying problem of non-native fish eating all the razorback’s larvae and juveniles.”

Robin Silver, the center's co-founder, said the threat extends beyond the Canyon.

"In the Verde and Salt rivers, between cattle grazing, destroying streamside vegetation, and the non-native sport fish introduced by Arizona Game and Fish Department, this magnificent creature, literally a living dinosaur, is becoming functionally extinct in Arizona," he said.