The dinosaur fish that lost its reproductive mojo: Meet Missouri’s fish helpers

On a chilly December morning, four people man a small boat on the Missouri River near downtown Kansas City where the Kansas and Missouri rivers converge.

They’re searching for a great white fish.

For an hour or so, they yank gill nets from the waterway, mostly pulling up logs.

Then something live wriggles over the bow.

“It’s a pallid!” yells Cliff Wilson, a resource science assistant for the Missouri Department of Conservation.

Well, it looks like a pallid sturgeon, a species both threatened with extinction by man and now curiously reliant on humans to breed.

The lunker pulled on board is bigger than the shovelnose sturgeon tangled in the same net. It’s paler. Its anatomy has all the right distinctions to suggest it’s not just an overgrown shovelnose — dangling whiskers arrayed in the proper crescent formation, smoother belly, longer nose.

More promising yet, it looks like something reared in the wild. The wave of an electronic wand over the fish shows no signs of the ID tag that would have been injected into a hatchery fish. Those stocked in the river sometimes also bear a sort of tattoo or a harmless notch in a dorsal scale. None here.

This sucker is headed to what amounts to a stud farm for fish, the Neosho National Fish Hatchery.

It’s places like that, rather than in the wild, that pallid sturgeon eggs turn into infants that hold the potential to grow to adults.

The rare sturgeon, a squat and spiky whopper dwelling in the murky bends of the muddy Missouri, proved frisky enough to outlive the dinosaurs.

For eons, as the planet saw untold number of species come and go, the pallid sturgeon bred one generation after the next. Its very survival signaled the big fish’s longstanding prowess at making little fish.

Lately, not so much.

Now it takes a village of scientists to breed a pallid sturgeon.

Coddling ichthyologists

Biologists snatch rare live pallid sturgeon from the Missouri River, analyze their genetics and fatten them on rainbow trout. Ultrasounds and endoscopies explore sturgeon gonads to pinpoint just the right time to dose the fish with hormones to extract and artificially fertilize their eggs.

Live males and a meticulously cataloged sperm bank near Atlanta are kept at the ready to build the best genetic stock possible when an exceptionally hard-to-find pure-bred female pallid sturgeon turns up.

Only when the fertility crews succeed in nurturing the resulting offspring to their juvenile stage are the spiny little buggers set free in the Missouri. Those young hatchery fish survive at reasonable rates in the river.

Yet there’s little evidence that pallid sturgeon — when left to their own, ancient devices — have much luck spawning in the wild any more. These fish need help.

“It’s a bit of a mystery,” said Kasey Whiteman, a resource science supervisor for the Missouri Department of Conservation. He’s part of a far-flung team of scientists and river managers teamed from myriad state and federal agencies trying to save the pallid sturgeon.

Solving the riddle of the endangered fish that seemingly can’t breed on its own comes with complications from the rivalries of the Missouri River.

Tweaking the waterway to better accommodate the pallid sturgeon, and hopefully kick-starting its natural reproduction, sets off howls from those who want to store more water in upstream dams for recreation, those who want a reliable channel deep enough to float barges, those worried about flood control and a host of other forces tugging this way and that.

All the while, efforts continue to coax along the pallid sturgeon until the dwindled species once again maintains its population without help from man.

So far, it’s mostly hope.

Starting in 2005, teams scoured the Missouri River looking for baby pallid sturgeon hatched in the wild. Hatchery fish stocked into the river, identifiable because they carry the same tiny electronic tags people use to identify their cats and dogs, proved plentiful.

But those hatched in the wild? Fewer than a dozen have turned up in the last decade-plus, and there’s troubling evidence that those young fish aren’t surviving to adulthood.

“Are they actually not reproducing, or is it that the little ones aren’t surviving? We just don’t know,” said Joe Bonneau, chief of the threatened and endangered species office at the Omaha district of the U.S. Army Corps of Engineers. “It’s a hard question.”

Great white fish

The sucker plucked from the Missouri and headed to the Neosho National Fish Hatchery first gets one of those electronic tags. It’s injected with some antibiotics to boost it for the three hours or more it will spend in the back of a pickup truck swimming in a 90-gallon aerated galvanized steel tank filled with Missouri River water.

A splinter-size bit of a fin is clipped and stored in a vial for DNA analysis. That wisp of fish tissue will tell biologists the specimen’s sex and whether it’s truly a pallid sturgeon. Pallids and shovelnose are cousins that often breed with each other. The resulting hybrid offspring typically look deceptively like pallids.

Eyeballing the yard-long fish, Missouri Conservation Department resource staff scientist Thomas Huffmon guesses its age at at 12 to 15 years. If he’s right, that means it’s just reaching its reproductive years.

“Finding these things is like a needle in a haystack,” he said.

If the sturgeon proves to be a fully wild pallid — not from a hatchery, not a shovelnose mutt — it’ll end up in an indoor tank in Neosho, Mo., run by the U.S. Fish and Wildlife Service, for a year or more, depending on its fertility cycle. (Space can sometimes get tight, and some fish are transferred to one of a half-dozen hatcheries as far away as Montana.)

“They get really fat and happy here,” said Bruce Hallman, the hatchery’s education specialist. “We aim toward spawning them in the best shape we can.”

Finding any wild-born pallid sturgeon is an encouraging sign. But catching an adult underscores the inability to spot any younger pallids in the river.

“When we see (an adult) wild pallid sturgeon, it was spawned a decade or more ago and no spawning since that time leaves you with an aging population with nothing behind it to support it,” said Whiteman of the Missouri Department of Conservation. “You are left with a group of old individuals that will eventually die.”

The hatchery is hoping for females because they’re harder to find. If this fresh catch is female, an endoscopy will examine the ovaries. The nucleus of an egg will be studied to check on timing. A big fish can produce up to 15,000 eggs, a third of which might create little fish that survive the first year and get stocked in the Missouri. Of those, fewer than a dozen might live to adulthood.

Wild and fallow

Even by fish standards, the pallid sturgeon ain’t pretty. A pale, toothless, bony creature draped in sharp scales, it slithers through murky waters with creepy barbels dangling below a triangular snout sniffing for something worthy of its bottom-sucking mouth.

The lazy and wild Missouri, where the fish made its lair for millennia, has been dammed up in its northern reaches and tamed into a barge ditch in its lower stretches. Neither offers the slow-moving, murky water that’s cradled the Scaphirhynchus albus for so long.

The federal government added the flat-nosed muck lover to the endangered species list in 1990, embroiling the fish in always testy fights about the management of the Missouri River.

Three things matter for species survival: habitat, habitat, habitat. (In the broadest terms, biologists see this as the mystery to the fertility question. The more specific answer, still lacking, is what’s politically and practically possible for restoring natural elements of the river.)

Virtually everything that’s happened to the Missouri in the 20th century was bad for pallid sturgeon real estate.

Upstream dams made for great game fishing of northern pike and other breeds that the Dakotas and Montana now bank on for tourism. It also provided modest tools to limit flooding through Iowa, Nebraska and Missouri.

Downstream channelization — carving out a trough for shipping — made barge traffic practical. (That shipping peaked at about 2 million tons of cargo in the 1970s. It’s now about a quarter of that.)

Both developments were bad for the pallid sturgeon. The fish do poorly in the deep, northern reservoirs. Likewise, the narrowed and faster-moving sections below Gavins Point Dam make for a lousy home.

“You had a channel that was as much as 3,000 feet and narrowed it to 600 feet,” said Gerald Mestl, a fisheries biologist and Missouri River program manager for the Nebraska Game and Parks Commission. “That eliminated a lot of critical habitat” of slow-moving water clouded with organic material that nurtured the pallid sturgeon for thousands upon thousands of years.

When pallid sturgeon eggs hatch, the larval fish drift for up to two weeks before they can swim on their own. So today, with a river moving at 5 mph, pallid sturgeon hatched in Sioux City, Iowa, could easily get flushed into the churning Mississippi River in a week. Even if they didn’t wander that far, the Missouri current could be too stiff for them to handle.

Mestl sees at least one obvious solution — and one that appears out of reach. Widen the river. For starters, flooding bottomland with a fatter, slower, more shallow river would mean buying millions of acres from private owners. The controversy would be unending. Court battles would easily span decades. The barge industry would fight back.

Instead, biologists experiment on the fringes, literally, of the river.

Some have experimented with dumping lawn clippings in the river to restore more of the organic material that natural flooding once provided. Work is ongoing now to revise dikes on the river — spacing them differently to more closely mimic the river’s natural edges, creating eddies of slower water of varying depths.

The Army Corps of Engineers, the ultimate boss of anything that happens on the Missouri, has carved out side channels and dredged chutes to create small side-channel islands that provide more river edges. That’s appeared to provide some haven for older fish and those stocked in the river.

But there’s still virtually no signs of wild spawning. And recently, biologists tracking the pallid sturgeon have been talking about “skinny fish syndrome.”

Some pallid sturgeon actually shrink over time, suggesting that they’re not thriving in the river, that their sexual organs are developing more slowly. Even healthy members of the species don’t spawn every year. Fish pulled from the river in less-than-robust shapes suggest that breeding cycle might be even more drawn out.

“We don’t know exactly what the species needs,” said Jane Ledwin, a biologist with the U.S. Fish and Wildlife Service. “(But) putting parts of the river back together will go a long way.”

This story was originally published December 15, 2016 at 6:41 PM with the headline "The dinosaur fish that lost its reproductive mojo: Meet Missouri’s fish helpers."