Prehistoric Fish Hang On

CHAMOIS, Mo. "This is a real uncertain thing," said Fisheries Management Biologist Craig Gemming as he motored downstream from the Mokane boat ramp at 8 a.m. March 6. Nearby, in a backwater of the Missouri River, three fisheries workers were preparing to haul the first of five nets up from 30 feet beneath the surface of the Missouri River. We could find lots of fish, or there could be almost none."

As the 200- by 10-foot net emerged from the mocha-colored water it exposed a writhing, scaly jackpot, glittering like moist treasure in the early morning sun. The crew set to work gently extracting sturgeon, scaly, prehistoric-looking fish, from the square-meshed gill nets and depositing them in a holding tank. The crew identified and measured each fish, recording species, length and weight on data sheets.

Gemming calls sturgeon Missouri’s aquatic dinosaurs. They evolved during the Jurassic Era, when dinosaurs roamed the earth. "It’s a real shame that these fish have thrived for 150 million years only to come to the brink of extinction in the last 100 years." said Gemming.

As pallid sturgeon recovery plan coordinator for the Missouri Department of Conservation, it is Gemming’s job to see what can be done to prevent the pallid sturgeon from losing its battle for survival. To do that, he has to have some handle on the species' numbers, and the only way to get that is to go out and find them.

Late winter isn’t the most convenient time to look for pallid sturgeon, but it is the most effective time. March finds the cold-blooded creatures stacked like cordwood in deep scour holes behind rock wing dikes. The water is a few degrees warmer at the bottom of such holes than at the surface.

Rather than trying to count all the pallid sturgeon in Missouri, Gemming and other Conservation Department workers conduct an annual sturgeon survey. They set nets at the same time each year. The number of fish they catch can be affected by water level and other factors, but each annual survey provides a statistical snapshot of pallid sturgeon populations. Over time, the annual data reveal trends, up or down. So far, the trend isn’t good.

Since we began looking at pallid sturgeon numbers, we have seen a decreasing trend," Gemming said. "I'd say we see half as many now as we did 20 years ago."

In their most recent survey on the Missouri River in central Missouri, Gemming’s crew netted 799 sturgeon. Of that total, 19 were lake sturgeon, two were pallid sturgeon, and one was a pallid/shovelnose sturgeon hybrid. The largest of the lake sturgeon weighed 25 pounds. The largest of the pallid sturgeon weighed 4 pounds. Pallid sturgeon can grow to 80 pounds. Few grow to larger than 10 pounds, however.

Gemming was pleased with the lake sturgeon catch. "In my previous four years of sampling, I have only taken 12 lake sturgeon," he said. "It’s too early to say if this reflects an increase in the number of lake sturgeon present or if this was just a lucky year. Either way, though, it’s nice to see."

Regarding the two lonely pallid sturgeon and a hybrid that turned up in this year’s sample, Gemming was less positive. "They are still here, but they are hanging on by a thread. We need to do everything we can to help this species out," said Gemming. Gemming knows once that thread is broken, pallid sturgeon are gone for good – extinct, off to join most of Missouri’s other dinosaurs.

Besides advocating changes in river management, the Conservation Department is stocking captive-reared pallid sturgeon to augment the existing wild population. In 1994, MDC released 10,000 16- to 18-inch pallid sturgeon spawned artificially at Blind Pony Hatchery near Marshall. It stocked another 3,000 in 1997.

Gemming said the stocking program is an important part of pallid sturgeon recovery efforts, but rearing the fish in captivity is tricky and doesn’t yield large numbers of fish year after year.

Although surveys are picking up good numbers of shovelnose sturgeon on the Missouri River, the catch rate on the Mississippi River is significantly lower. He says that could be related to commercial harvest of the fish, both legal and illegal. "Since the sturgeon population in the Caspian Sea crashed several years ago, there has been a tremendous demand for sturgeon roe for the caviar trade. With caviar selling for more than $275 for a 14-ounce tin, we are seeing a huge increase in the number of shovelnose sturgeon taken from the Mississippi River."

Gemming says the skyrocketing cost of caviar and the caviar trade could be part of the reason for this difference in shovelnose catch between the Missouri River and the Mississippi. "It’s one of the primary reasons we started the monitoring project," he says."

The pallid and lake sturgeon declines began with unregulated commercial fishing in the 18th century. At that time, lake sturgeon were quite common. The fish lived as long as 150 years, reaching weights of more than 300 pounds. Thousands were killed and discarded just to prevent damage to fishing nets. Their flesh was so oily that steamboats sometimes burned them in their boilers. Rendering plants processed them for oil and fertilizer. In the 19th century, sturgeon came into favor for their flesh and for their eggs, or roe, which produced fair-quality caviar.

Today, the Conservation Department regulates commercial fishing. This makes it easier to prevent excessive harvesting of sturgeon. Current regulations allow commercial anglers to take only shovelnose sturgeon and only those less than 30 inches long. But sturgeon face other problems, and those same problems plague other fish and wildlife, too.

Gemming says that in the past 100 years, 28 percent of the Missouri and Mississippi rivers have been converted to reservoirs. On the Missouri River, the change has taken place mainly in North and South Dakota, where enormous reservoirs now cover what once was hundreds of miles of prime sturgeon habitat. On the Mississippi River, locks and dams back up deep, narrow, lake-like corridors that are of little use to sturgeon, which are adapted to life in flowing water.

River channelization has taken a toll, too. Restricting the Missouri and Mississippi rivers to narrow, deep, swift-flowing channels for the benefit of barges has reduced the livable area of the rivers by half.

Finally, humans have altered the way the rivers levels change seasonally. Under natural conditions, the Missouri and Mississippi would rise in the spring in response to rainfall and snowmelt. In the late summer and fall, their levels would drop drastically. These natural variations in flow produce a variety of habitats, from flooded bottomland to exposed sand bars and extensive areas of shallow, slow-flowing water. Today, however, the U.S. Army Corps of Engineers holds water in reservoirs during the spring and releases it throughout the dry months. This keeps river flows high enough to sustain barge traffic, but it also reduces the natural diversity of habitats needed by sturgeon and other wildlife.

"Even with protection from well-designed fishing regulations, sturgeon face an uphill battle," says Gemming. "Most of the places where they once could spawn and find food have disappeared. It isn’t easy to bring a species that has survived 150 million years to its knees, but channelizing and damming the Missouri River has done it."