"This was the decision we have been hoping for," said Cassie Mellon, native aquatics program coordinator for the Utah Division of Wildlife Resources (DWR).
"The state and the entire least chub conservation team has been working to protect and conserve this species to ensure it didn't need to be listed," Mellon said. "What this means is that the entire species is not imperiled and this nonlisting finding really validates that."
The conservation agreement was signed by federal and state agencies as well as the Southern Nevada Water Authority. The water authority had been promoting a plan that could have threatened water levels in southwestern Utah, where some of the existing populations of least chub remain.
"Given the partners' long-term history of commitment to conserving this species, we are confident that continued conservation of this unique fish in Utah will be secure into the future," Noreen Walsh, director of the Mountain-Prairie Region of the federal wildlife agency, said in a prepared release.
Fish and Wildlife officials ruled in 2010 that the least chub deserved protection under the Endangered Species Act, but put any action on hold because other species required attention first.
The Center for Biological Diversity said it recognizes that some positive changes have occurred since the 2010 announcement, but said the fish should remain a listing candidate.
"The least chub occurs in just a tiny fraction of the streams it once occurred in and remains very fragile. Endangered Species Act protection would have ensured that conservation efforts continued and were successful," Noah Greenwald, endangered species director for the center, said in a release Monday.
"We're glad some of the threats to the least chub have been reduced," he said, "but given its limited range and other ongoing threats, this unique little fish clearly still warrants endangered status."
Utah biologists have been creating "refuge" populations in addition to protecting existing historic populations of the native least chub in the Snake Valley of the West Desert and the Sevier River and Utah Lake drainages. A mature fish is about two inches long.
"One of the big things the conservation team wanted to do was try to produce additional populations so if something bad were to happen the entire species would not be completely lost," Mellon said.
There are currently 10 such confirmed refuge populations, including a unique one in a spring on Antelope Island. Another 10 refuge populations are "in limbo" but could eventually be confirmed, Mellon said.