Katie Creighton, native aquatics project leader at the Moab Field Station of the Utah Division of Wildlife Resources, was giddy.
“We've decided to open the gate this morning to start welcoming these baby razorbacks into their new home for the first time!” she wrote in a May 18 email to the Moab Sun News. “We are beyond excited!”
Creighton was referring to a fish nursery at the Scott M. Matheson Wetlands Preserve designed to support razorback sucker fish, one of only 12 fish species native to the upper Colorado River basin. The razorback sucker has been on the endangered species list since 1991, and over the past three decades the Utah DWR has partnered with various other conservation agencies to try to help the species recover.
The gate that Creighton mentioned was completed this past fall, and is the second construction phase of a three-phase nursery at the Matheson preserve, which, if successful, will give juvenile razorbacks a healthy place to grow without the threat of predators. Last week was the first time the gate was opened to welcome the young fish into the wetlands.
Razorback sucker fish endangered
The razorback sucker fish is named for a recognizable bony hump just behind its head, which helps it stay stationary in strong currents, according to a 2018 US Fish and Wildlife article. It’s found only in the Colorado River and its tributaries and can live for more than 40 years and weigh up to 14 pounds.
However, in the early stages of its life, the razorback is very small and subject to predation by nonnative fish. In addition to being eaten by these non-native species while young, adult razorbacks must compete with nonnatives for resources.
Matt Breen, native aquatics project leader for the northeastern region for the Utah DWR, said that while there are only 12 fish species native to the upper Colorado River basin, the introduction of nonnative fish has brought the species count up to over 50.
Changes in historic river flows pose another threat to these fish.
“Adult razorback suckers migrate hundreds of miles during high spring river flows to spawn,” says a May 14 press release from the Utah DWR about the species, issued in honor of Endangered Species Day, which was observed on May 15. “To survive and escape predators, their recently-hatched larval offspring need to drift downstream and enter into any nearby wetlands.”
In their natural rhythms, Colorado River flows used to rise and ebb with the seasons and would flood wetlands and riverbanks. Human infrastructure like dams and levees built all along the Colorado River regulate and direct those historic flows—leaving tiny young razorbacks with almost nowhere to shelter while they are small.
“Wetlands provide a nursery environment with quiet, warm water — and better food sources — allowing the fish to develop and grow,” the DWR press release reads. “Having this type of habitat is critical because these small fish have few defense mechanisms at this stage, especially against predators.”
Razorback recovery efforts have been underway since 1988 with the establishment of the Upper Colorado River Endangered Fish Recovery Program. Fourteen collaborating agencies began raising razorbacks in hatcheries and releasing them into the Green River to rebound adult populations. However, scientists found that the fish were not successfully reproducing in the wild.
In 2006, the Bureau of Reclamation altered operations of Flaming Gorge Dam, in northern Utah, which manipulates the flow of the Green River, a tributary to the Colorado River.
Under new protocol, the dam releases water each spring to mimic natural seasonal flooding and create the floodplains razorbacks need to thrive. It took several years for scientists to realize that the initial timing of the releases did not line up with razorback spawning season; after further study, in 2012 the Bureau of Reclamation started releasing flows from the Flaming Gorge Dam when biologists had detected the infant razorbacks, in what’s called their “larval stage,” into the river. These releases flood places like the Stewart Lake Waterfowl Management Area along the Green River near Vernal, Utah, creating wetlands hospitable to the larval fish.
“Stewart Lake has proven to be an ideal place to help young razorback suckers in their historical nursery habitat,” DWR Native Aquatics Biologist Michael Partlow said in the press release, explaining that the management area already had structures that allow biologists to control how water enters and leaves the wetlands.
The agency added screens to those control structures that would allow the tiny larval razorbacks in, but shut out large predators like smallmouth bass and northern pike, as well as competitors like carp, Partlow said.
Stewart Lake is drained each fall. Before that happens, managers release the young razorbacks into the Green River. Since 2013, 4,000 juvenile razorbacks have been released from Stewart Lake. Many of the fish are tagged with tracking devices with unique identification codes so scientists can track them when they are recaptured.
“Last year we saw an individual that had grown up to 3 years that we had originally raised at Stewart,” said Breen.
Scott M. Matheson Preserve
The fish nursery in the Scott M. Matheson Preserve is intended to serve a similar function for razorback suckers, though it will rely on natural flows of the Colorado River rather than deliberate releases from a dam like the Stewart Lake Wetlands.
The nursery consists of a concrete channel that provides an inlet from the Colorado River into the wetlands preserve with a screened gate that controls the flow in and out of a safe pond. Like the Stewart Lake wetlands, the Matheson Preserve offers rich food sources, warmer waters, and a haven from large predators.
Creighton described the early stages of the razorback life cycle. “Razorback suckers spawn on cobble bars in the main channel as spring flows increase,” she said. “Once larvae hatch, they drift until they can wiggle their way into off-channel habitats that provide shelter from the fast, cold spring run-off as well as a warm, nutrient-rich environment in which to grow. Success relies on razorback sucker larval drift coinciding with rising river flows that will flush these little guys into the warm, protected, nutrient-rich waters of the Preserve.”
Over the last several weeks, Creighton and her team have observed razorback sucker larvae in the inlet channel, and they decided it was time to finally open the gate. On Monday morning, she and two other DWR scientists, Karen Burke and Zach Ahrens, gathered around the gate and pushed the hydraulic button that activates it. Creighton said the lack of fanfare was almost a letdown after five years of working on the project.
“It took, like, five minutes for it to really, really, really slowly open up,” Creighton recounted with a laugh. “And then, nothing.”
No red ribbons were ceremoniously cut; instead, the gate quietly let the waters of the Colorado flow in. The young razorbacks will be kept in the wetlands for as long as water quality can be maintained.
"Once water quality begins to degrade, a natural phenomenon as water levels drop, we will release the young fish back to the Colorado River,” Creighton said.
That will give the razorbacks only a couple of months or so to get big and strong enough to survive in the river. It will still be a challenge for the juvenile fish, which will still be only about a couple of inches long.
“Historically these fish could spend a couple of years in a wetland,” Creighton said.
In the third and final phase of the nursery construction project, the pond area will be dredged out to make it wider and deeper, and it will be linked to springs in the preserve for an additional water source. These improvements will enable managers to keep the young razorbacks in the wetlands for longer, improving their chances of survival.
However, even a couple of months in a safe place raises their chances of reaching adulthood.
A success story
In 2018, U.S. Fish and Wildlife services announced they would begin considering “down-listing” razorback sucker fish from endangered to threatened. The process involves reviews by scientists from various agencies and can take a long time; no decision has been made yet on the species’ status. However Breen said that the possibility of down-listing the species is a big deal.
“If you look at the number of species that have actually come back from the endangered species list, it’s very few. Only one fish species has been removed from the list,” Breen said.
“It’s a very significant thing... Had we not taken action, they would have gone extinct.”
Even if the species does get down-listed, monitoring efforts and recovery actions will continue.
“There are lots of processes to this. It’s not an immediate thing to take a species off the list,” Breen said, explaining that reviewers are looking for certain criteria to be met such as how well the species can sustain itself in the wild, and what populations of different life stages are present within its range.
“A lot of people think that sucker fish are ‘trash fish,’” Breen said. But he said razorbacks play a vital role in the ecosystem, cleaning the river environment through bottom-feeding habits, digesting algae and plants. They turn those plants into food for other animals who prey on the razorbacks. They are also a “vital indicator species,” Breen pointed out.
“If razorback sucker populations are doing well, the ecosystem is in good balance overall,” he said.
He also expressed gratitude to all the agencies that have contributed to the recovery effort.
“We could not accomplish these things without the great working relationships we have with our many partnering agencies in the Upper Colorado River Endangered Fish Recovery Program, and most importantly without the patience and support of members of the public,” he said.
“Endangered species recovery is an enormous effort and it takes time and patience.”