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Sometimes, when you glimpse an endangered species in its native habitat, it becomes a story you can’t wait to tell everyone back home. A monkey swinging through the rain forest canopy, a sea turtle laying its eggs on the beach, a tundra flower blooming in a gravel field. But the pair of 10-inch-long razorback suckers I watched a group of biologists pull from nets in Lake Mohave one warm March morning — and then gently measure, scan, and return to the water — didn’t make my heart skip. They just looked like a couple of slim brown fish.
The story is not in what I saw, but what I didn’t. Within seven 300-foot-long nets strung in shallow coves, those two suckers were the only representatives of their dwindling species, outnumbered by dozens of corpulent, oily Asian carp.
Over five days of checking the nets morning and evening, Paul Marsh — a former Arizona State University professor who now runs an independent native fish research lab — and his crew netted 23 razorback suckers and 184 carp. Elsewhere on the lake, nets strung by teams from the U.S. Bureau of Reclamation, the U.S. Fish and Wildlife Service, and state wildlife agencies fared little better: They snagged a total of 129 razorback suckers and 282 carp, plus a smattering of other fishes not native to the Colorado.
The groups had gathered on Lake Mohave, a translucent stretch of dammed-up Colorado River on the Arizona-Nevada border north of Laughlin, for the annual weeklong ritual of the Razorback Roundup. Each year for the past two decades, fish biologists from around the Southwest have traveled here to monitor the sucker population, hoping to save it from oblivion.
The razorback sucker (Xyrauchen texanus), one of the four endangered fishes of the mainstem Colorado, is admittedly more fetching in its full-grown glory than the young specimens I met on the lake. Yellow-bellied and fleshy-lipped, the adults, which can grow to 13 pounds, have distinctive keel-like humps just behind their heads. Early Western settlers called them humpback suckers and buffalo fish. When the Colorado ran wild, the fish were abundant, their soft and bony flesh regularly consumed by Native Americans. In the late 1800s, settlers plucked them from the water with pitchforks and used them as livestock feed and fertilizer.
Razorbacks survived in Lake Mohave long after the Davis Dam filled the reservoir in the early 1950s. In fact, the lake once contained the largest population anywhere in the Colorado River Basin.
But by the mid-1980s, scientists had made a worrisome discovery: The Mohave population was still made up largely of the same fish originally trapped by the dam. The razorbacks had spawned year after year, but their hatchlings were snapped up by young green sunfish, channel catfish and other thriving non-native species. Meanwhile, the adult fish were inching closer to the end of their half-century life spans. The population was headed for a massive crash.
Today, after millions of dollars and decades of time spent trying to save the razorback, something is still going wrong. Next year marks 20 years since the fish was officially listed as endangered, but its numbers continue to drop.
“It’s a challenge,” said Marsh, an aquatic ecologist who has devoted 30 years to native fish conservation. His crew worked the nets of his 21-foot motorboat while he stood at the helm, pondering the future of the razorback sucker. “What do we do? How do we change our approach?”
Saving the larvae
One clear night, with the lake so flat you could see the Milky Way reflected on its surface, Marsh edged the boat close to a small rock overhang on the Nevada shoreline and cut the engine. He sank a small light into the water, and soon you could make out scores of tiny wiggling white creatures with little black dots for eyes. They were razorback sucker larvae, hatched just a few days earlier at this spawning ground, Tequila Cove.
Roundup participants had already captured several thousand of them here and delivered them to Willow Beach National Fish Hatchery, at Lake Mohave’s north end, where they would spend two weeks in an aquarium dining on artificial plankton, spirulina algae, powdered brine shrimp and other delicacies before moving on to indoor and then outdoor raceways. Each year, Roundup participants collect up to 30,000 larvae and ferry them upstream to the hatchery. They remain there for four years, reaching about 19 inches in length. At the end of that time, the surviving fish — between 6,000 and 10,000 of them — are tagged with tiny microchips (not much bigger than a staple and $5 apiece) and returned to the lake.
These larvae, if left on their own, had virtually no chance of survival. Unless they were caught and taken to the hatchery, they would be eaten by non-natives in a matter of days.
Year after year, biologists and hatchery workers go to the enormous trouble of capturing, transporting, raising and releasing the razorbacks for one simple reason: If the razorback has a future, these Mohave hatchlings carry it in their genes. In the Lower Colorado River Basin — the section below Glen Canyon Dam — razorback suckers continue to hang on in Lake Mead, to the north of Lake Mohave, and in Lake Havasu, to the south. Those populations, though, are genetic subsets of the Mohave razorbacks. Lake Mohave, in other words, is the motherlode of razorback DNA.
In the mid-1980s, between 60,000 and 75,000 razorback suckers lived in the lake. By the turn of this century, there were fewer than 3,000. Today, scientists believe only about 50 of those wild fish and their lake-raised offspring survive. Despite more than two decades of research and conservation efforts, the population continues to dwindle. Up to 1,500 “repatriates,” the fish raised at Willow Beach from wild larvae, are probably also swimming in Mohave’s waters — but those amount to less than 1 percent of the 150,000 hatchery-raised razorbacks that have been returned to the lake since 1992.
In spite of the unabated decline, Marsh perseveres. “I’ve spent a 30-year career watching the animals I love and work on go down the toilet despite my best efforts,” he said. “For us, as a species, to allow these animals to be extinguished is fundamentally wrong. It’s a philosophical thing.”
It’s an outlook shared by Tom Burke, the fishery group manager for the Lower Basin’s multispecies conservation program at the Bureau of Reclamation, who has been a linchpin of razorback recovery efforts here for three decades. Burke waxes poetic about the river, and he’s smitten by the razorback’s tenacity. “They evolved in a river of extremes,” he said. “These fish are capable of withstanding 200-plus million metric tons of sediment a year coming out of Grand Canyon. That’s, well, it’s a bunch.”
A tough neighborhood
The Colorado River was always, in Burke’s words, “a tough neighborhood” for fish, not only because of its famous sediment load, but also because of its wide fluctuations in water volume, temperature and salt content. The razorback’s 50-year-lifespan, he explained, gave it a fighting chance of producing at least one surviving offspring. But then humans made the neighborhood even tougher: We crisscrossed it with dams, and stocked it with voracious fish from far-off lands.
In the 1950s and early 1960s, government officials also routinely poisoned waterways, killing native species in order to stock sport fish like rainbow trout. Using money given to the states from taxes on recreational fishing products, government officials poisoned 2,500 miles of streams and 225,000 acres of lakes in 34 states, according to Anders Halversson, whose new book, “An Entirely Synthetic Fish,”chronicles America’s love affair with rainbow trout.
In 1962, the Wyoming and Utah wildlife agencies orchestrated the ne plus ultra of fish genocide, a massive effort to poison native fish using the chemical rotenone. The idea was to create a clean slate on the Green River — a main Colorado tributary originating in Wyoming’s Wind River Range — above the soon-to-be- completed Flaming Gorge Dam, eradicating all life in the water and then filling it with millions of rainbow trout. Using a series of “drip stations” strung along 450 miles of river, as well as airboats and helicopters, officials killed off 450 tons of fish in three days. “As the rotenone front progressed downstream,” writes Halversson, “it drove large schools of desperate fish in front of it, a sight that deeply impressed itself on those who saw them ‘thrashing about and struggling for air on the surface of the river.’ “
Today, the idea of poisoning rivers and lakes is shocking — unless it’s to kill exotic species to protect native fish populations. But the second part of the Flaming Gorge strategy, stocking game fish, remains standard practice up and down the Colorado. In the Lower Basin alone, more than 100 non-native fish species have either become established in reproducing populations or are continually re-stocked. In the eight years following the Green River poisoning, according to Halversson, fish and game officials filled Flaming Gorge Reservoir with upwards of 20 million rainbow trout. The stocking continues today.
At Willow Beach, a short drive south of the Hoover Dam in Arizona, rainbow trout grow in raceways just yards away from the razorback suckers’ pens. Every Friday, year-round, 2,000 rainbows are set free in Lake Mohave.
Predators and prey
In 2006, Abraham Karam, a young biologist working for Marsh, implanted acoustic transmitters in 20 hatchery razorbacks and released them into the lake. The fish averaged 15 inches in length, the standard size they reach in one to two years at Willow Beach. Within less than six months, 16 of the transmitters had stopped moving, meaning the fish were dead. Another one of Marsh’s biologists, Brian Kesner, recovered 13 transmitters by diving to the lake floor.
Karam’s research fingers striped bass, the only fish whose mouths can open wide enough to munch 15-inch-long prey. (A subsequent study involving razorbacks 19 inches and longer found that the larger fish survive better.) He’s convinced that the stripers, which were initially stocked in Lake Mead but spilled over the Hoover Dam during a high-water year in the early 1980s, are flourishing in Lake Mohave thanks to a nearly unlimited food supply: stocked rainbow trout. Well-fed, the bass have become formidable. Anglers regularly reel 40-pound stripers from the lake, and Nevada’s record-setter, weighing 60 pounds, was caught on Mohave in 1998. Now, these colossal fish are devouring the hatchery-raised razorbacks — along with bonytails, an even more perilously endangered native fish.
Karam is amassing additional evidence from Mohave fishermen. One angler found an acoustic transmitter — one of those lost in Karam’s study — in the stomach of a striped bass caught just a couple of miles from where the tagged fish were released.
Others have noted the problem. On an online message board run by a popular lure company — one striped bass model they sell is called “hatchery trout” — a die-hard bass fisherman recently wrote, “For the green people who spend all of our tax money raising suckers, I have a word for them: The lake is full of predators and they are eating machines. When you stock suckers, the predators come from far and wide and go on a feeding spree. They eat all of your hard work raising suckers. Doesn’t that register with you?”
Dueling priorities
An alphabet soup of conservation and recovery plans has been created to protect the razorback sucker. In the Lower Basin, the fish is part of a federal conservation plan, a $626 million, 50-year, 43-species effort launched in 2005. In the Upper Basin, more than $120 million in federal funds has already been spent on razorback sucker recovery efforts. According to some estimates, an additional $84 million could be spent by 2023.
On the upper river — much of which still resembles a river — the initial recovery projects focused mainly on improving and regenerating habitat: regulating flows, simulating floods, restoring gravel bars. Those efforts have been largely fruitless. “You’d like to see more fish in a bigger range,” said Harold Tyus, a University of Colorado at Boulder professor who wrote the recovery plan for the razorback sucker while working for the U.S. Fish and Wildlife Service. “What are we seeing? Less fish and in a smaller range.”
Some Upper Basin watchers see the story as one of missed opportunity, in which state officials continued to stock non-native fish long after they should have known better. Colorado, for instance, stocked largemouth bass in the Elkhead Reservoir, near the town of Craig. Despite screens intended to prevent the fish from escaping, they’ve spilled over the dam and now dominate some stretches of the Yampa, a tributary that flows through the northwestern part of the state.
Which brings us to the built-in, largely intractable problem that looms over native fish recovery efforts: State wildlife agencies, which cooperate with the federal government on endangered species recovery, derive their revenue from recreational fishing. As Tyus put it, “The very agencies you’re dependent on to recover the fish are the very agencies that are responsible for their plight.”
Because sport fishing is big business — for the agencies as well as local economies — it’s likely here to stay. People who enjoy catching rainbow trout and striped bass and other species that didn’t evolve in the Colorado River ecosystem are not about to give up their right to do so. (Marsh impishly pointed out that Burke likes to catch stripers on Lake Mohave, sometimes delivering filets to Marsh’s camp during the Roundup.) Halversson, in his book, cites a 2005 Fish and Wildlife Service economic analysis of stocking programs: Every dollar spent growing and stocking rainbow trout led to $32 of economic activity.
Angela Kantola, assistant director of the Upper Colorado River Endangered Fish Recovery Program for the Fish and Wildlife Service, said the states have greatly improved their fish-stocking practices in recent decades. “The problem isn’t stocking the fish,” she said. “It’s controlling the fish that are already in the system.” In the Upper Basin, said Kantola, recovery agreements now prevent states from stocking sport fish where they’ll be harmful to native fish, but she acknowledged that the states’ dual roles “require some give and take, and some continued research.”
Upper Basin vs. Lower Basin
So the turf wars continue — and stretch far beyond feuds between sport-fishing advocates and native species conservationists. Within the conservation community, antagonism and lack of cooperation between the Upper and Lower basins shadows the future of the razorback sucker and its fellow endangered fishes. Lower Basin advocates are wont to complain that the Upper Basin has gotten most of the money — oversight for native fish recovery on the entire Colorado lies with the Fish and Wildlife Service’s Denver office — and wasted it on habitat restoration when the real problem was non-natives.
Those focused on the Upper Basin, meanwhile, tend to dismiss the Lower Basin efforts as futile, given that nothing approaching ecosystem-scale recovery can ever take place in what is essentially a system of reservoirs. While some environmental groups have participated in the various Lower Basin conservation initiatives, none of them have given the razorback sustained support. “The river had been so transformed that it was a question of what could possibly be accomplished there,” said Dan Luecke, a hydrologist and longtime participant in Upper Basin efforts, recalling a long-ago decision by the group Environmental Defense not to join an early Lower Basin recovery program.
But to the Lower Basin’s champions, the fact that adult razorbacks survived for years in Mohave is proof that the efforts remain worthwhile — even imperative. Just because there are dams on the river, they say, is no reason to give up on native species that evolved there. Tom Dowling, an ASU geneticist, recalls a talk he gave at a fisheries conference several years ago, after which an audience member asked why Dowling was worried about biodiversity if the presence of non-natives meant there were now more species living in the river than ever before. “He asked, ‘Isn’t that a good thing?’ ” Dowling said. “I was like, ‘You’re missing the point completely!’ As conservation biologists, it’s important to understand what the different units are and try to preserve them. They co-evolved with the system.”
Saving endangered species
So is it worth the effort? Does it make sense to set ourselves up as perpetual caretakers, indefinitely footing the bill and bearing ultimate responsibility for these creatures’ presence or absence from the planet?
We work to save endangered species for many reasons. We do it for their genetic legacy, their place in the ecosystem, their commercial value, their moral right to exist. Sometimes it’s simply for the love of a fascinating natural creation. Yet there is one overriding reason that binds us all, whatever our beliefs: Protecting endangered species is the law.
Scientists who have spent their careers trying to save the native fish of the Colorado often wonder if their efforts will, ultimately, make any difference. “We’re almost 30 years after the last amendments to the Endangered Species Act were passed in ’73,” said Marsh, “and no one would argue that native fishes of the Southwest are in better shape today than when the act was passed. We’re actually losing ground.”
But he, for one, refuses to give up just yet. Politics might change, attitudes might change, some sort of breakthrough is always possible. “I guess I hope that if we knock on the door long enough that the door will open and things will move forward in a more meaningful way.”
Hillary Rosner of Boulder is heading to Cambridge as a 2010-11 Knight Science Journalism fellow at MIT.
