Wildlife biologists in Utah are trying to bolster the state's population of roundtail chub, a fish endemic to the Colorado River system. The fish is listed as a sensitive species in Utah due to habitat loss and competition with invasive species.
About 30 round tailed chub were released recently into the Old City Park pond in Moab as part of a statewide project to boost the native fish population.
Tyler Arnold, a wildlife biologist with the Division of Wildlife Resources in Utah, says roundtail, like many of our native species in the Colorado River system, has been on the decline
"Actions like this actually help propagate and promote these fish so they don't end up on the endangered species list. Propagation gives us the ability to actually put these fish back into the system and expand their numbers so maybe they can thrive a little better," he said.
Roundtail chub are endemic to the Colorado River system and are only found in the Four Corners region and parts of California.
In the past couple of decades, dams and droughts throughout the river system have hurt their numbers. On top of low water levels, invasive species in the river system, like shiners, catfish, and bass, have been throwing the whole native fish ecosystem out of whack.
"You know, these fish kind of interacted with the other native fish, like suckers and Colorado pikeminnow. You know, they were a food source for Colorado pikeminnow. So they're kind of one of the stepping stones to the pyramid that we have for our ecosystem," said Arnold.
Arnold doesn't expect to have spawning fish next year but hopes to see small fish the year after that.
"For me, success would be in the next two years if I start seeing little fry on the shoreline," he said.
Arnold says eventually, they'll release some of the chub at Old City Park back into the Dolores River, where they came from.
"We'd like to put them in the exact same spot until we get a better understanding of how we can continue to propagate these," he said.
"And then as our management plan develops more for how we want to address roundtail and watersheds, then like Mill Creek would be the next, you know, we want to stay with the nearest neighbor because then we start getting into genetic issues."
Arnold says fish in the Dolores River are more apt to deal with warm temperatures, like two or three degrees warmer, as a result of these genetic variations.
"They just developed that way over the last couple thousand years versus a population in the San Rafael may be used to a colder temperature. But once you mix them in the same watershed, one would do better than the other because of just that slight variation in the genetic code. You know, those are the considerations we have, we wanted to keep because once we start mixing and we start having conversations about, oh, are we playing too much of a role with the environment."
The pond at Old City Park has been kind of an unofficial ecological experiment in the past few years. In 2021, the city had to remove non-native carp because they were so big they were eating ducklings.
They've also had to remove goldfish from the pond.
"You know, somebody didn't want to get rid of their pet a different way so they put it out in the natural environment," he said.
The pond is also home to a couple of farm geese.
"So the people get them for their backyards to protect their chickens and stuff like that. They don't fly. So somebody had to dump that here," said Arnold.
The geese aren't interested in eating fish. Neither are the ducks that live there. In fact, the roundtail chub is the only fish living in the pond right now. Arnold and his co-workers did a survey of the pond earlier this year to make sure the roundtail chub wouldn't be competing with other species.
He says there are other considerations when a new fish is being introduced to a water system.
"We had to do a quarantine on these fish because in the Dolores River, we do have Asian clam, which is an invasive species we have in the Colorado River system," explained Arnold.
"We've basically been having to starve them for the last three days so that they can expel and kind of purge themselves. And if the Asian clam or its eggs were at a certain age where they're like a small shell, they actually can pass through the whole digestive system unscathed."
Arnold and his colleagues are hopeful that the elevation, temperature, and food availability in this pond will be perfect for the roundtail chub to survive.
"But it was actually really just kind of a collaboration with the city of Moab wanting to do something with this pond. It had carp and goldfish prior, and they came to the division asking how and what can we do with this to make it more natural?'"
A pond isn't a traditional habitat for a roundtail chub. The fish prefers to be in large river systems like the Dolores, Colorado, Green River, and the San Rafael River, says Arnold.
"So this is going to be a little bit of a different situation for them, but they can survive. It's been successful in Wyoming. They've done the same kind of activity."
Arnold says as long as the fish can find spots in the pond that are oxygenated and the temperature is right, they can still spawn.
"I mean, like I said, other states have had success with round tail spawning in other ponds," he said.
This storywas shared with KSUT via Rocky Mountain Community Radio, a network of public media stations in Colorado, Wyoming, Utah, and New Mexico, including KSUT.
Copyright 2023 Aspen Public Radio.
