An endangered fish has returned to the Santa Cruz River near Tucson after a 70-year absence,
According to the Arizona Department of Game and Fish, the Gila topminnow returned to the river much in part due to upgrades to a wastewater treatment facility that released effluent into the river in 2013.
The fish was rediscovered in the Santa Cruz near Nogales in 2015.
"Finding Gila topminnow in the net was unexpected," said Ross Timmons, a native fish biologist with Arizona Game and Fish, in a statement. "After this previous summer's runoff, we were expecting to find different native fish, the longfin dace, but instead we found Gila topminnow."