Can pallid sturgeon hang on in the overworked Missouri River?

  • Pallid sturgeon at Gavins Point National Fish Hatchery near Yankton, South Dakota. These fish, all 7 years old, will be used as breeders for this critically endangered species once they reach at least 15.

    Joel Sartore/www.joelsartore.com
  • A pallid sturgeon netted in the Lower Missouri River.

    USGS
  • Fisheries technician Dave Fuller pilots a boat on the Upper Missouri River, keeping tabs on the fewer than 150 wild pallid sturgeon that persist there.

    Marian Lyman Kirst
  • Gonadal biopsies help researchers Dave Fuller (blue jacket) and Pat Braaten (camo) determine if a reproductive female has spawned.

    Marian Lyman Kirst
  • Gonadal biopsies help researchers Dave Fuller (blue jacket) and Pat Braaten (camo) determine if a reproductive female has spawned.

    Marian Lyman Kirst
  • Gonadal biopsies help researchers Dave Fuller and Pat Braaten determine if a reproductive female has spawned.

    Marian Lyman Kirst
 

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Despite Intake's reputation as the pallid's best -- and cheapest -- shot at recovery in the Upper Missouri, the project is controversial. Any money spent on Fort Peck or Intake is money that can't be spent on recovery and restoration elsewhere on the river -- building aquatic habitat in the Lower Missouri, for example. This has angered some downstream biologists, who are not convinced that enough wild pallids currently swim all the way to Intake, or spawn in the upper river, for the project to matter much. (Only two or three fish typically make it to Intake each year.) Others believe that even with passage, embryos still won't have enough room to develop before hitting Lake Sakakawea.

Since the Upper Basin dams likely aren't going anywhere, some argue the Corps should focus money downstream. The Lower Missouri's fish have problems too, including water contaminants that have caused deformities to their reproductive organs, and hybridization. And young wild fish haven't been found there either: thousands of embryos have been genetically tested, but only one was a pallid, and it was collected in the Mississippi.

But unlike the Upper Basin populations, Lower Basin fish enjoy access to thousands of miles of free-flowing river, which means no devilishly complicated drift issues. Plus, the Upper Basin's wild heritage population will almost certainly die out within the decade. This won't end the species as a whole: Scientists have preserved roughly 90 percent of the Upper Basin pallids' genetic diversity in hatchery fish, some of which are finally reaching sexual maturity. But unless the drift issue is figured out, their offspring will meet the same fate as their wild brethren: death by reservoir.

Braaten understands the interest in Intake. "The Yellowstone is one of North America's premier rivers," he says. "It's relatively free-flowing with a natural hydrograph and thermal regime that is hard to find anywhere else in world. When you have a highly endangered species living there that has passage problems at one of the dams, common sense says improve passage."

On the other hand, Braaten says, "You have the Missouri, a highly impacted system where we know pallids were historically. So you have two situations for enhancing populations." Why not try to do them both? "Intake will be an experiment just as Flow Mod was," he says. And Flow Mod was foiled by drought, leaving unanswered the question of how pallids would react to flow changes and increased temperatures on the Missouri.

Nevertheless, in 2009, the Corps officially terminated Flow Mod. Braaten and Fuller would still share an office and a mission -- pallid sturgeon recovery in the Upper Basin -- but their research territory shifted. Braaten was assigned to the Yellowstone; Fuller, the Missouri below Fort Peck.

Not long after that, in 2011, the Missouri River Basin experienced a 100-year flood event. Throughout the Upper Basin, record snowpack and spring rains triggered massive runoff. To protect Fort Peck's structural integrity, the Corps had to release surface water over the spillway. The river raged for weeks.

For Fuller and Braaten, it was an ironic meteorological twist of fate. "We felt it imperative that someone be out there to document the pallids' response to the record flows," says Braaten. The crews mobilized: Fuller and his guys on the Missouri, Braaten and his team on the Yellowstone. The huge flows were a stroke of good luck. Getting crews out there, says Braaten, required foresight.

And it paid off. Pallid sturgeon migrated nearly 200 miles up the Missouri toward Fort Peck and the Milk River. "We had never seen that before," says Fuller. Spring after spring, pallids would leave their wintering grounds below the confluence and swim into the lower Yellowstone. But last year, 16 wild fish went "as high up (the Missouri) as we could have expected them to come."

What's more, in early July, Fuller and his crews located what looked like a spawning aggregation, when fish gather for a big, piscine orgy: the females release their eggs on the riverbed while the males swim nearby, broadcasting sperm. Six days later -- about as long as it takes eggs to hatch and begin their drift -- Fuller and company returned to sample for embryos. They positioned themselves downstream from where the spawning aggregation had occurred, and tossed in their net.

"I did not have my hopes up at all," says Fuller. "We were sampling such a small fraction of the (river)." Yet they did net some embryos, which they sent off for genetic testing to determine if they belonged to pallid sturgeon, shovelnose or paddlefish.

Finding a wild embryo has long been one of the effort's "Holy Grails" -- a sought-after sign that pallid survival in the post-dam era is even possible. Last December, Fuller received some incredible news: One of the embryos was, in fact, a pallid sturgeon -- "the first genetically confirmed wild-produced pallid (embryo) collected anywhere in the Missouri River Basin," he says. "It was a giant haystack with probably just a few needles. We got lucky, there is no doubt about it." He called his boss. "I was worried he wouldn't be that excited because he's more of a walleye guy," he recalls. But his boss went out and bought two bottles of champagne. The men spent the afternoon celebrating.

Since Fuller went public with his discovery, the tiny embryo has been the talk of the recovery community. "The Service built its original (plan) on the hypothesis that if you can restore historic flow and temperature conditions, pallids will respond," Braaten says. "That appears to be exactly what happened." What's more, Fuller's finds -- the spawning aggregation and the embryo -- show that the dammed Missouri below Fort Peck doesn't have to be "a terrible, inhospitable, crappy place" for pallid sturgeon, Braaten says.

For others, though, last year churned up more questions than answers. "The fact that they captured one pallid (embryo) is huge," says Steve Fischer, the senior program manager for the Corps' Missouri River Recovery Program. "But how many were actually spawned that year? Can we find them again, or were conditions just right last year? And, if so, what might those conditions have been?"

"It tells us that wild fish will spawn and eggs can hatch in the wild," agrees Jordan. But, he says, whether the embryos survived their drift between dams is still unknown. If in the next few seasons crews start finding wild, young fish, then, Jordan says, we will know that they've recruited on their own, and "the champagne can really flow."

Given the massive property damage caused by last year's flooding, in Braaten's mind, the biggest question now is whether pallids will respond as well to much less extreme flows -- the kind it might be possible to release from Fort Peck on a more regular basis. "What would it take?" he wonders. The experimental spills prescribed by Flow Mod were less than half the volume of last year's emergency spillway releases. "Could we get away with something less?"

If the answer is yes, it may still be possible to help the fish below Fort Peck by modifying dam releases to more closely mimic natural conditions. If the answer is no, the pallids' future in the upper river looks far less bright, and passage at Intake might be their only shot. After all, the Corps would be hard-pressed to elicit public support for pallids if, to save the species, it essentially had to flood the Missouri Basin every spring. On the other hand, the Intake project has faced significant design setbacks, delays and cost increases, and is still controversial.

"There is a lot of jabber going on about putting emphasis back on Fort Peck and this section of the Missouri," says Fuller. The Service, he says, now has solid evidence to pressure the Corps to follow through with flow and temperature changes below Fort Peck. This year, the Corps held meetings to discuss the feasibility of fitting Fort Peck with a temperature-control device that would funnel warm water from the surface of the reservoir to the dam's lower intakes instead of using the spillway. This would increase temperatures below the dam -- and, ideally, compel pallids to migrate up the Missouri to spawn -- without increasing flood risk or interrupting the dam's hydroelectric operations.

In the end, says Fischer, the Corps has to decide if it's cheaper to invest in Intake or pursue changes at Fort Peck. "We have to take into account the social, cultural and economic impacts," of each project, Fischer says. "We have to factor all of those in to our management actions."

Last July, just a week before Fuller collected his embryo, Braaten made an important -- though sobering -- discovery of his own.

Braaten and a USGS technician had spent the day tracking telemetered pallids on the Yellowstone. As they were driving back to Fort Peck, Braaten received a call from a hydrologist who'd also been on the river that day. He asked if Braaten saw the dead pallid near the bank. "Are you sure it was a pallid?" asked Braaten. "Oh yeah," the hydrologist replied. "And it reeked."

Braaten drove back and walked the bank until he found the corpse, afloat amid a tangle of vegetation. It was easily four feet long, says Braaten, "one of our heritage fish." The smell "was horrible and mostly undescribable," he says. "I've smelled many a dead fish in my days, but the pallid odor was different -- at least to me."

He scanned its tag: It was a female that was captured in 2007, taken to the Miles City Fish Hatchery and spawned. Since then, 10,000 of her progeny had been stocked in the Upper Basin. It was comforting to know that she had some descendants out there, Braaten thought.

The fish was the first dead pallid he'd ever found. The fact that he was there to identify her was just dumb luck, he says. What are the odds with so few fish out there?  "(Maybe) it's another commonality that Dave and I share -- working with hard odds and coming up with something."

Braaten believes the pallid succumbed to old age; a poignant reminder that, despite Fuller's heartening discoveries, the upper river's wild pallids are on their way out. When Braaten got home that night, he sent an email to colleagues describing the fish and its fate. The first line read, "Sad day on the river."

Marian Lyman Kirst is a former HCN editorial fellow and a freelance science writer with a passion for nature's weirdest and most wonderful creatures. She currently lives in Sanmen, China

This story was made possible with support from the Kenney Brothers Foundation.