GRAND CANYON — Biologists have released endangered fish into a Grand Canyon creek to try to improve their chances of survival.
The release of humpback chub into Bright Angel Creek in May follows efforts to remove trout that prey on them.
The humpback chub once was widespread throughout the Colorado River basin, but its numbers have declined. The largest population now is in Grand Canyon National Park.
Biologists say establishing populations outside the Little Colorado River should help the fish thrive.
The humpback chub released in Bright Angel Creek are tagged with microchips so biologists can track their growth and survival. An antenna downstream from the Bright Angel Campground tracks their movement.
Anglers who catch humpback chub or other protected native fish must return them to the water.