Environmentalists Oppose Reclassification of Rare Colorado River Fish Due to Drought

A rare fish found exclusively in the Colorado River basin has been brought back from near extinction thanks to years of protection, but environmentalists must continue the work to ensure its survival, federal authorities said in a Monday statement reclassifying the species from endangered to threatened.

The humpback chub, named for a fleshy bump behind its head, was first recorded as endangered in 1967 when its habitat was disrupted by dam construction. Also, the introduction of predatory, invasive aquatic species caused the humpback chub population to decline.

The status change for the will take effect November 17 under a rule published Monday in the Federal Register by the U.S. Fish and Wildlife Service.

For more reporting from the Associated Press, see below:

Humpback Chub
The humpback chub, a rare fish found only in the Colorado River basin, has been brought back from the brink of extinction after decades of protection, though continued work is needed to ensure its survival, federal authorities said October 18 in reclassifying the species from endangered to threatened status. This undated photo provided by the U.S. Fish and Wildlife Service shows a humpback chub in the Colorado River in Colorado near the Utah border. Travis Francis/U.S. Fish and Wildlife Service via AP, File

Environmentalists oppose the endangered status delisting. They argue the humpback chub's future remains in peril as a megadrought, largely attributable to climate change, diminishes flows in the Colorado River basin, which includes seven Southwestern U.S. states and Mexico.

The delisting comes two months after the U.S. Bureau of Reclamation declared an unprecedented water shortage on the river. It also follows a July Fish and Wildlife proposal to move another rare Colorado River fish, the razorback sucker, from endangered status to threatened.

Jen Pelz, Wild Rivers Program Director at the environmental group WildEarth Guardians, said in a statement that it was "perplexing that the [U.S. Interior Department] would be going to so much trouble to reclassify these endangered fish at a time when so much uncertainty exists regarding climate change and the ability to continue to fund the suite of heroic measures it undertakes annually for these species to survive."

Both the Fish and Wildlife Service and the Bureau of Reclamation are part of the Interior Department.

The government considers a species "endangered" if it is in danger of extinction in all or much of its historical habitat. Protections are kept for "threatened" species, and that status means biologists can take steps to improve the overall population even if some of the fish might be hurt.

Fish and Wildlife said it finalized another rule to ensure that work with other parties—including private, state, tribal and federal agencies—continues to maintain its existing habitat and diminish the threat from predators and drought-induced water flows, among other preservation efforts.

The largest population of the humpback chub is in the Grand Canyon, with more than 12,000 adult fish. Four smaller wild populations are upstream of Lake Powell in Utah and in Colorado canyons. The species thrives in rocky waterways with swift currents but needs warm and muddy water to spawn.

The fish once had a broader range, but the construction of the Flaming Gorge Dam in Wyoming and Hoover Dam on the Nevada-Arizona border led to two other populations of the species becoming extinct. An eighth population in Dinosaur National Monument also is considered gone.