Arizona Public Radio | Your Source for NPR News
Play Live Radio
Next Up:
Available On Air Stations
Science and Innovations

Humpback chub reclassified from endangered to threatened

Humpback Chub
Randall Babb
Arizona Game and Fish Department

The US Fish and Wildlife Service has downlisted a Colorado River fish from endangered to threatened. KNAU’s Melissa Sevigny reports, the agency says the humpback chub is on its way to recovery.

The humpback chub was listed as endangered in 1967 under a law that preceded the Endangered Species Act. It’s harmed by dams that change the Colorado River’s flow patterns and temperature, as well as by exotic fish that eat young chub.

The Fish and Wildlife Service says the chub’s populations have stabilized after fifteen years of efforts to improve habitat by altering dam management and removing exotic predators. The agency says there are now more than three thousand adult fish in the Upper Basin of the Colorado River, and more than twelve thousand in the Lower Basin, primarily at the Little Colorado River confluence in the Grand Canyon. Dropping water levels in Lake Mead have also helped the chub by exposing new river habitat.

But some environmental groups decry the decision to downgrade the species’ legal protections, citing concerns about dams, drought, and climate change.


Melissa joined KNAU's team in 2015 to report on science, health, and the environment. Her work has appeared nationally on NPR and been featured on Science Friday. She grew up in Tucson, Arizona, where she fell in love with the ecology and geology of the Sonoran desert.
Related Content