Death of a dinosaur: Pallid sturgeon a short step from extinction

2003-08-17T23:00:00Z Death of a dinosaur: Pallid sturgeon a short step from extinctionMARK HENCKEL Gazette Outdoor Editor The Billings Gazette
August 17, 2003 11:00 pm  • 

Ken McDonald summed up the plight of the endangered pallid sturgeon this way: "In the wild, these fish are now essentially extinct. They're not able to reproduce on their own, and they haven't reproduced in decades. Pallid sturgeon are still swimming around out there, but as a species, they are functionally extinct."

That's a gruesome picture for this native fish species of Montana's middle and lower Missouri and lower Yellowstone rivers.

Yet McDonald, special projects bureau chief for Montana Fish, Wildlife and Parks and the chairman of the Upper Missouri Basin Pallid Sturgeon Recovery Group, meant every word.

"Right now, there are between 160 and 200 adult pallid sturgeon in the Missouri below Fort Peck Dam and the Yellowstone and 30 to 50 in the Missouri above Fort Peck," McDonald said.

"These are old fish. There hasn't been any documented pallid reproduction in the past 35 years at least," he added. "They will all be gone, based on their ages, by 2016. They will die of old age. That's our best guess.

"But even that doesn't take everything into account," McDonald said. "These are old fish. By tomorrow, they could be too old to reproduce. At some point, their age will become too old to reproduce. They'll become senescent. They'll get too old. It's like us when they get old. They're out there and they're living and functioning but not able to produce young.

"Unless things change," he said, "as a species, the pallid sturgeon's time on earth could be done very soon."

For this fish, that time on earth has been very long one. According to the U.S. Fish and Wildlife Service, pallid sturgeon evolved from a group of fish that lived with the dinosaurs 70 million years ago during the Cretaceous Period.

In many ways, pallids still look like a dinosaur. With a flat, shovel-shaped nose, the fish have bony plates, called scutes, on their backs that run from head to tail. The tail itself is thin and long.

Pallids are sort of a pale white/gray in color. They have four barbels - some incorrectly call them whiskers - under their chins. The two inner barbels are shorter in length than the outer two. On their close relative, the shovelnose sturgeon, all four barbels are the same length.

Pallid sturgeon can live upward of 50 years. And they can grow big, with mature adults weighing as much as 80 pounds.

As to what they eat, pallids grow to be a top-end predator.

"In the early stages of life, they eat invertebrates and zooplankton (underwater insects)," said Steve Krentz, a U.S. Fish and Wildlife Service supervisory biologist in Bismarck who leads the nation's Pallid Sturgeon Recovery Team. "When they're five to ten years old, they change over to primarily a fish diet, feeding on minnows and other fish species.

"They're really quite an effective predator," Krentz added. "They do well in turbid (muddy) river systems and they've got sensory organs on their head, their barbels and their body that allow them to find and prey on fish species even in very turbid waters.

"They can also find their way around in those turbid waters very well," he said. "They can detect other fish, detect changes in current, temperature and velocity of water."

In modern times, pallid sturgeon have been a resident of just the Missouri River system, including the Yellowstone, and the Mississippi River system. Throughout their range, the species isn't doing well. It's not just a problem in the big rivers here.

Question biologists about what parts of these rivers that pallids like best, and are likely to use the most, and you'll find out they tend to use many parts of the river.

"They use a variety of habitats," Krentz said. "They're often associated with sand bars in the main channel. Turbidity is important. They'll use fast water and slow water. You'll also find them in the deep holes. Really, the old Missouri River as it functioned is obviously the best habitat. They use a lot of it."

The loss of the old Missouri River with the coming of big dams such as Fort Peck in Montana, Garrison in North Dakota and Oahe, Big Bend, Fort Randall and Gavins Point in South Dakota have changed the rules of life for the pallid sturgeon and not for the better.

The coming of these dams has changed the character of the river and cut it up into sections separated by big reservoirs. This left the pallid sturgeon in such tough shape that it was officially listed as a federal endangered species in 1990.

Since then, things have only gotten worse.

"The situation is scary right now for pallid sturgeon. The situation is dire," McDonald said. "It frustrates me no end that we can't do more for this species. It frustrates me that more people don't care about them. These fish are one step away from extinction."

Mark Henckel is the outdoor editor of The Billings Gazette. He can be contacted at 657-1395 or at henckel@billingsgazette.com.

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