Curtains for the Pallid Sturgeon

Can biologists breed the “Dinosaurs of the Missouri” fast enough to stave off their extinction?

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It's cold. Here on the North Dakota-Montana border they're predicting rain, then freezing rain, then snow, up to 15 inches. Not ideal fishing weather. Still, I have traveled to the confluence of the Missouri and the Yellowstone rivers with 15 wildlife conservationists and government scientists to search for a species perilously close to extinction. We're fishing for Scaphirhynchus albus, the pallid sturgeon.

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They call it the "Dinosaur of the Missouri," although whether for its age or its appearance is a tossup. The pallid looks more at home in a natural history museum than on the end of a fisherman's line. It has a flat, upturned shovel of a nose; long, fleshy whiskers called barbels; a knobby back; and bony protrusions called scutes, rather than scales, lining the gray skin of its body. The fish, which can weigh 80 pounds, can live 60 years or longer. For about 70 million years, since the height of the dinosaur age, the pallid sturgeon and its ancestors reigned as a top carnivore in the vast river system that drains the middle portion of the North American continent. Pallids were harvested for their flesh and their caviar, like their Russian cousins, until they were listed as endangered in 1990.

The fish is perfectly adapted for cruising the nearly opaque waters. Its eyes have shrunk to the size of beans; instead of using vision, sensors in its head detect the electric fields of prey burrowed in shallow muck. Its scoop of a snout stirs up mud in search of small fish and aquatic insects. Tucked into the fish's flat white underside is a toothless mouth that folds in like a telescope, ready to shoot outward in a flash to suck up prey.

The trouble is, the river in which pallids flourished no longer exists. In Mark Twain's day, "the turbulent, bank-caving Missouri," as he called it, changed its path capriciously, especially during spring floods, which could be devastating. The river tore up trees and hid them below the surface, where they snagged passing boats. It was dangerous for people to live near, and sometimes fatal to navigate.

Twain wouldn't recognize today's Missouri, tamed as it has been by the U.S. Army Corps of Engineers over the past century. It's been deepened and straightened—which has shortened it by hundreds of miles. Its banks have been lined with dikes and rocky barriers called revetments. Six major dams punctuate its path. Flooding is far less common. The seasonal high and low waters are gone, as is much of its turbidity: the Big Muddy has cleared considerably.

The high waters of spring signal the pallid to spawn, but in these meticulously managed waters, this very endangered species has not reproduced successfully for years. There are fewer underwater tree snags where they can find food and fewer shallows where their larvae are safe from predators. It's estimated that fewer than 10,000 live in the Yellowstone, Missouri and Mississippi rivers from Montana to the Gulf of Mexico; those that survive are oldsters, and they are not being replaced by new generations. The population here, in the South Dakota and Montana river system, is down to about 200 aging adults.

"Plus or minus 70," says George Jordan.

Jordan, of the U.S. Fish and Wildlife Service, is the leader of the Pallid Sturgeon Recovery Team, the crew braving the weather today. The team's goal is to catch up to 38 pallids—ideally at least a dozen females—and transport them to hatcheries where hormone treatments will induce them to breed.

Five shiny aluminum motorboats are launched. Jordan teams up with Fish and Wildlife Service colleagues Steve Krentz and Bill Bicknell, and I hop aboard with them. Krentz pilots the boat, and Jordan and Bicknell will fish. All wear waterproof neoprene hip waders. In addition, Jordan sports nifty neoprene gloves with no fingertips. He's prepared to haul nets, draw blood delicately with a syringe or jump in the river up to his chest to rock a grounded boat free.

Yesterday, a boat with a radio telemetry antenna detected signals up the Yellowstone River from pallids that had been previously tagged with transmitters. Krentz steers the boat in that direction.


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