Kansas City, Mo ? The world’s hunger for caviar is threatening the existence of the shovelnose and pallid sturgeons that roam the bottom of the Missouri and Mississippi rivers.

A federal ban placed this month on imports of caviar from the beluga sturgeon in the Caspian Sea has ignited an already-strong demand for eggs from the shovelnose sturgeon.

Scientists say that demand poses a growing danger for the shovelnose’s cousin, the pallid sturgeon, which is already an endangered species. It looks and reproduces much like the shovelnose, and it gets caught in the same nets.

“The stakes have gotten pretty high,” said Edward Grace, a special agent for the U.S. Fish and Wildlife Service.

On much of the Missouri and Mississippi rivers, commercial and recreational fishermen can legally take the shovelnose sturgeon but are expected to throw back any pallid sturgeons they catch.

Experienced commercial fishermen insist it is easy to tell the two types of sturgeon apart.

But amateurs might not sort out the species so easily. And the pallid sturgeon can grow much larger, meaning a female with a bellyful of environmentally priceless eggs can net a fisherman a quick $200 in caviar trade.

“The only way to catch somebody is probably through undercover operations,” said Jim Milligan, a fisheries biologist involved in endangered species restoration for the U.S. Fish and Wildlife Service. “That can take two or three years with no guarantee.”

Until this month’s ban, the United States imported 80 percent of the world’s beluga caviar, most of which came from the Caspian Sea. Now, suppliers are looking elsewhere for the black, salty fish eggs.

One response has been a small industry of farm-raised sturgeon and paddlefish. Osage Catfisheries in south-central Missouri years ago began raising paddlefish for their roe.

Now, the company ships L’Osage Caviar worldwide, raising part of its catch in golf-course water hazards and housing subdivision ponds.

“It’s only getting bigger,” said Jim Kahrs, who runs the fish-raising operations with his sons.

But it can take eight to nine years for a paddlefish, and nearly as long for most sturgeon to grow old enough to produce eggs.

A much quicker investment is to buy a $25 Missouri commercial fisherman’s license to go after the sturgeon that swim in the rivers.

Catch increasing

Historically, the norm for the annual sturgeon catch on the Missouri River in Missouri had been about 1,000 pounds. Through much of the 1990s, the catch was about 3,000 pounds. It rose to 7,000 pounds in 1999 and to 10,000 pounds in 2001.

On the banks of the Mississippi River in Missouri, a sturgeon harvest of 5,000 pounds a year for most of the century hit 20,000 pounds in 2000 and 65,000 pounds last year.

Short of DNA analysis, it is virtually impossible to sort the eggs of the beluga from the endangered pallid or the shovelnose.

“My guess is that most of these guys know the difference between a pallid sturgeon and a shovelnose sturgeon,” said Milligan, the fisheries biologist in Columbia.

“I suspect there’s a smaller contingent that doesn’t care. : If you get a 10- or 15-pound pallid, you could have 5 to 8 pounds of eggs worth 100 to 200 bucks. That is an awful lot of money for somebody who in a typical day may not make enough to pay for his gas.”

Edwin Nichols, a meat cutter and sometime fisherman from Hartsburg, said telling the pallid from the shovelnose was easy.

The pallid, as its name suggests, is a lighter color. Its fleshy whiskers, called barbels, come in different lengths, while a shovelnose’s tend to be uniform. The pallid’s belly is smoother and generally lacking the bony plates on the underside of shovelnose.