The U.S. Fish and Wildlife Service announced this week that it has removed Utah’s least chub from a waiting list to be included on the Endangered Species List.
Prior to Monday’s decision, the least chub was considered “warranted but precluded” under the Endangered Species Act. Precluded means the least chub met the criteria to be considered an endangered species, but was not yet included under the act because other species were considered higher priorities.
But, according to the U.S. Fish and Wildlife Service, statewide conservation efforts have successfully reversed the decline of the least chub, leading to the decision to remove the fish from the candidate species list.
The least chub, a tiny fish that scientists believe was native to Lake Bonneville, is found only in six known populations in Utah. There are no known native populations in the county, but thousands of least chub live in two refuge ponds at the Tooele Army Depot South Area.
The least chub were introduced to the local ponds in 2011, after employees at Deseret Chemical Depot restored and replanted the ponds with a refuge in mind. The state Division of Wildlife Resources cooperated with the effort, and seeded the ponds with fish from a native population of least chub in Mona.
The Mona Spring population was considered one of the most endangered populations of least chub, because the springs had been colonized by mosquitofish, a nonnative species brought to the area to control insects that is rapidly displacing the least chub in some areas.
The DWR brought the fish to Tooele with the intent of breeding a back up population that could be used to bolster the native population in Mona Springs.
As of a count last fall, the DWR had determined that the least chub at Tooele Army Depot were nearly ready for reintroduction at Mona — just another success story for the least chub in recent years, said Mark Grover, a DWR biologist who specializes in native aquatics.
“The main reason given for delisting was our success at establishing these refuge populations, so we were pleased that the work paid off,” he said.
However, Grover added that he had a mixed reaction when he first heard the news.
“I’ve been working on the least chub for five years now,” he said, “and I think the state as a whole really wanted to see this happen. But we’ve had a couple setbacks this year, so I was a little concerned that we weren’t out of the woods yet. But I do think it was the right decision, and that the species’ position is a lot more secure than it was a few years ago.”
Grover said the state had lost a population of least chub at Faust this year when a series of springs in the area dried up, and said there were other ponds with least chub populations that had recently been colonized by the invasive mosquitofish.
But, he said, conservation efforts intended to further improve the least chub’s comeback, will continue in the years to come.
“It should be business as usual, where if it had been listed [as an endangered species] our management would have changed,” Grover said. “This will give us a little bit more breathing room.”