LAKE MOHAVE — Nearly every detail of the soil bed beneath the water in the miles stretching up to Hoover Dam is discernible. Only wakes from boats and ripples from kayak paddles disturb the surface.
Fish are easily spotted.
While it’s a momentary delight for the boaters or kayakers, it can be a deadly reality for certain species. Following the regulation of the Colorado River and the introduction of non-native fish species, several of Arizona’s native fish were pushed to the brink of extinction. Coalitions of federal, state and tribal agencies have spent decades trying to save them.
Now, those same agencies are proposing to downlist one of those species — the razorback sucker — from endangered to threatened under the Endangered Species Act. This comes on the fins of a similar proposal to downlist another native fish, the humpback chub.
“We’ve pulled these species back from the brink of extinction and we’ve been able to establish populations despite it being a stressful period of time for the Colorado River ecosystem,” said Tom Chart, director of the Upper Colorado River Endangered Fish Recovery Program for the US Fish and Wildlife Service “What we’ve learned from the razorback is the importance of sustained and committed management.”
Conservation groups say the proposal is premature and that downlisting the fish will only jeopardize its long-term recovery.
“I love what’s happening with the razorback and it is great that we’re working to keep it around. But we’re still on Step One of the recovery process, which is to keep them from going extinct right now,” said Brian Kesner, a senior project manager for the Native Fish Lab of Marsh and Associates. “We have not yet learned how to keep razorbacks alive in nature long term and until we do that, we shouldn’t be downlisting them.”
Regardless of whether the razorback sucker keeps its endangered status, some aquatic wildlife managers say landscapes across Arizona and the West have been so altered by changing climates that certain fish species will now always need to rely on human intervention to survive.
The nose picks up the first clues that something is happening at the Willow Beach National Fish Hatchery. Then the ears, which register the steady splash of gushing water. As the sounds turn to white noise, the eyes spot the rows of cylindrical tanks arranged symmetrically across the room.
Intermittent plops add to the melody of flowing water as a timed-feeding mechanism releases food into the tanks. The food is devoured in seconds. In the time between plops, hundreds of larvae razorback suckers patiently circle the spot where they know food will eventually drop again.
Each year, thousands of larvae razorbacks are taken to the hatchery to help build populations of the endangered fish species, part of the Lower Colorado Multi-Species Conservation Program.
“The Lower Colorado River has changed a lot from its historic state. There are now things, like hydropower plants, that have changed it from a once free-flowing river, with natural flooding and lots of turbidity, to what we have now which is a very controlled, regulated system,” said Jim Stolberg, the fisheries group manager for the conservation program. “This changed the relationship between native and non-native fish, mostly giving non-natives the advantage.”
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At the fish hatchery, the captured razorbacks are reared in what Stolberg calls “protective custody.” Once grown, they are reintroduced to Lake Mohave — the reservoir downstream from Lake Mead — and the rest of the Colorado River.
“Our program area is from Lake Mead all the way down to the international border with Mexico,” Stolberg said. “We introduce fish at Lake Mohave, Lake Havasu and below Parker Dam, which in total is about 400 miles of river.”
After decades of management, the US Fish and Wildlife Service is proposing to downlist the razorback sucker from endangered to threatened.
“Species move from endangered to threatened when we’ve gotten them to the place where we don’t think they are in danger of extinction, but we still are concerned that they could be in danger of extinction in the foreseeable future,” Chart said . “In threatened status, a species basically receives all the same protections that an endangered species receives. But this reclassification allows us to establish a 4(d) rule.”
In general, the Endangered Species Act prohibits the “take” of species listed as endangered. The act, however, includes Section 4(d) which allows for the take — including actions that may kill or injure — of species that are listed as threatened, as long as those actions do not interfere with the species’ overall survival and recovery.
“Some of these actions may have a negative impact immediately on the razorback sucker but in the long run are intended to help us recover the species,” Chart said.
This proposal comes within months of a similar bid to downlist the humpback chub. Chart confirms that the chub, found in the Colorado River as it flows through the Grand Canyon will be downlisted by the end of this year.
“The Fish and Wildlife Service will publish a final rule that downlists the humpback chub, but it’s not official until we get it into the Federal Registry,” Chart said. “The timing of these proposals is such because the science supports it. These fish are no longer on the brink of extinction. We are on a long, sustained commitment to the recovery of the species and we are done by no means.”
The service is accepting public comments on the reclassification proposal into September.
“There are four endangered Colorado River fish and we’re proposing downlisting two of those species because the science supports it,” Chart said. “We have been at this for 30 years, it is coincidental that we are making these decisions at a similar point of time.”
The proposal to downlist the razorback was met with resistance from wildlife conservation groups that believe it’s coming at the wrong time.
“I don’t want our reservations to cast a shadow over all the good work that has been done for razorback recovery, but this proposal is misguided. This endangered fish has a really daunting future,” said Taylor McKinnon, senior public lands campaigner for the Center for Biological Diversity. “There’s going to be more and more pressure on our limited water supply and wildlife managers will be faced with fewer options going forward for the endangered fish.”
The threat to Arizona and the West’s water supply was underscored in August when the Bureau of Reclamation declared the first-ever federal water shortage on the Colorado River.
While the steady decline of the river’s water level is a concern, Paul Marsh, owner and principal investigator of the Native Fish Lab of Marsh and Associates, says over-predation from non-native fish is still the largest threat to razorback recovery.
“My first reaction to the proposal was that it was premature,” Marsh said. “While we know a lot about this fish, we still don’t know how to solve the over-predation issue. The razorback sucker really isn’t in much better shape today than it was when it was originally listed as endangered decades ago.”
When released from hatcheries, like the one at Willow Beach, few of the razorbacks complete their “life cycle.” Many of the current fish populations, including the one at Lake Mohave, are reliant on human management and continued stockings.
Marsh believes that the fish being introduced to the river system by humans shouldn’t be included when assessing the threat of extinction for the species.
“The only reason we still have razorbacks in Lake Mohave is because we stock them. The only reason we have razorbacks in the Upper Basin stream is because we stock them. The only reason there are fish in the San Juan River is because we stock them. None of those populations are ‘recruiting’ meaning completing their life cycle,” Marsh said.
“If we stop stocking the fish, it will disappear. That’s on the brink of extinction,” he said. “We simply don’t agree with anyone who suggests that a species is not endangered if it is only surviving with very intense human intervention.”
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Electricity pulses into the water by Willow Creek as Sky Hedden and Stephen Farrar wade deeper into the tributary to the Little Colorado River.
Electro-backpack fishing is only the first step. Each fish Hedden stuns swirls to the surface, where Farrar scoops it into a bucket.
“Pretty neater in Arizona,” Farrar says with a grin.
Signaling is the second step. Setting aside the backpack and bucket, Hedden and Farrar split the weight of a trawl net and venture further into the water to capture the fish swimming too deep to be shocked.
With a bucket and a full net, the duo begin cataloging their catch, measuring the size of the fish and noting down their species.
The goal is to gauge how the Little Colorado River spinedace is doing. Hedden, the lower Colorado River coordinator for the Arizona Game and Fish Department, says most people might never see the native fish, which is listed as threatened under the Endangered Species Act.
“This species has intrinsic values in and of itself,” Hedden said. “A lot of the time the species that are starting to see population declines are indicators that there is something wrong with the system. Some people might not be concerned with this specific fish because it’s a species they may never see in their life. But it’s giving us an indication that something is wrong.”
The Little Colorado Spinedace has been listed as a threatened species for decades. Human expansion into the Southwest, paired with drier climates and regulated river systems, splintered the spinedace’s habitat.
According to Hedden, the multi-agency effort to save the fish “is a great example of how federal, state and tribal agencies can combine efforts to save endangered and threatened species.”
“As a young biologist, you’re not sure what to expect when getting into the field,” said Farrar, a recent graduate from the University of Arizona, who is interning with the department. “But the fact that I’m seeing and working with a threatened species, like the spinedace, is proof that it’s working and our conservation efforts aren’t in vain.”
While human intervention has undoubtedly kept the spinedace from extinction, Hedden says it is one of the native fish species in Arizona that will always depend on the human hand to survive.
“Humans have altered the landscape so much and, in many ways, permanently,” Hedden said. “The steady decline of water in Arizona has splintered the habitat for native fish and I’m not sure if we’ll ever get that back.”
There are three main populations of spinedace in Arizona. The current plan for its recovery, Hedden says, is to “replicate as many populations as possible” so that the species will survive even if an extreme event — like a wildfire or drought — wipe out one of the populations.
If the management of native species — like the spinedace — ever stops, Hedden says the fish will be back on the road to extinction within several seasons.
“It’s taken us 30 years to move the needle a little bit in the recovery of this species,” Hedden says. “The spinedace really highlights the amount of time, effort and money it takes to keep a species from blinking out.”
Follow Anton L. Delgado on Twitter at @antonldelgado†
Environmental coverage on azcentral.com and in The Arizona Republic is supported by a grant from the Nina Mason Pulliam Charitable Trust. Follow The Republic environmental reporting team at environment.azcentral.com and @azcenvironment on Facebook, Twitter and Instagram.