Fish tales

The pallid sturgeon lives at the bottom of the murky Mississippi River, but its struggle to survive has surfaced as an issue in plans to demolish the old Mississippi River bridge at Cape Girardeau.

Biologists on both sides of the river are working to save the pallid sturgeon, a fish with a long, pointed snout. The fact that the endangered, federally protected fish has been spotted in the river near Cape Girardeau will force a demolition contractor to work around the fish's spawning season even as the Army Corps of Engineers and fisheries experts explore ways to improve the fish's habitat.

Missouri Department of Conservation fisheries biologists say the spawning season in this area typically runs from late April through May. But when it comes to demolishing Cape Girardeau's rusting, nearly 76-year-old two-lane bridge, the contractor -- Tremont Foundation Corp. of Tremont, Ill. -- is barred from dropping any part of the span into the Mississippi River before Aug. 1 because of federal regulations cited in the project permit issued by the U.S. Coast Guard.

Scientists hope the restriction will help protect the fish -- added to the endangered species list in October 1990 -- particularly any fingerlings that might be living along the river bottom near the old bridge.

Scott Meyer, Missouri Department of Transportation district engineer in Sikeston, said the restriction won't stop construction crews from getting started on the nearly $2.23 million bridge demolition project this summer.

"There is a lot of work they can do before they drop anything in the river," he said.

Typically, the road deck is cut up and hauled off first. That debris can be hauled off without dropping any of it into the river, Meyer said.

The metal trusses then will be blown up and the debris hauled away for scrap. The concrete piers then will be blown up and that material will be hauled away, Meyer said.

Any demolition debris that falls into the river would have to be removed to meet permit requirements, he said.

The MoDOT staff plans to meet with the contractor next week to discuss the timetable.

Fish habitat

Pallid sturgeon live in the Mississippi River as far north as St. Louis and in the Missouri and Yellowstone rivers. They live on river bottoms in areas of strong current.

The fish, which prefer to locate near sandbars and strong currents, have been hurt by dams that have slowed the rush of water and channel dredging, according to the U.S. Fish and Wildlife Service. Commercial fishing and environmental contaminants also may be partly to blame, the service says.

Biologists have caught some fish that are hybrids of pallid and shovelnose sturgeon. Scientists worry that could lead to changes in the genetic makeup of the fish and threaten the long-term survival of the pallid sturgeon as a separate species.

Pallid sturgeon are slow to reproduce. Male pallid sturgeon reach sexual maturity from 7 to 9 years of age, with two- to three-year intervals between spawning. The females typically reach sexual maturity between 7 and 15 years of age, with up to 10-year intervals between spawning.

Those that survive into adulthood can live 50 years.

Fisheries scientists with the Missouri Department of Conservation, Southern Illinois University-Carbondale and the U.S. Army Corps of Engineers are in the third year of a three-year, $700,000 study of the pallid sturgeon.

The Corps of Engineers is looking at the possibility of building sandbars and side channels in the river between St. Louis and Cairo to boost the population of the endangered fish, said Dr. Jim Garvey, a professor of fisheries at SIU who is heading up the study project.

Finding pallid sturgeon isn't easy even for scientists because they are so few in number, Missouri Department of Conservation biologists said.

On Tuesday, conservation department biologist Joe Ridings pulled hundreds of feet of trotline from the muddy rushing current in the Mississippi River off Cottonwood Island in Perry County. After a couple hours of hard work, Ridings and two co-workers snagged only one sturgeon -- a shovelnose sturgeon which looks similar to the pallid sturgeon but isn't an endangered species.

DOC fisheries biologist David Ostendorf wasn't surprised by the group's lack of success. Ostendorf said fisheries biologists with the Mississippi River field station headquartered in Jackson, have caught, checked and released 11 pallid sturgeon since last July.

"It's kind of a big deal when you actually catch one," Ostendorf said.

The DOC monitors fish and water quality on the Mississippi River between Cairo, Ill., and Ste. Genevieve, Mo. But the pallid sturgeon monitoring has taken them as far north as St. Louis.

Most of the sturgeon caught have weighed about seven pounds. The largest one caught by the Missouri biologists weighed 13.5 pounds. It was caught at St. Louis.

The decline of the population is viewed as a warning that the overall habitat of the Missouri and Mississippi rivers is troubled.

Old photographs of pallid sturgeon show some fish 6 feet long and weighing 80 pounds. The fish's meat is palatable and its eggs have been valued as caviar.

SIU's Garvey said 55 of the endangered fish have been tagged by biologists involved in the pallid sturgeon project in the past two years. The project places sonic tags in the fish that allow scientists to track the "ping" to monitor their movements.

Fifteen buoys deployed in the river from Cairo to the mouth of the Missouri River contain receivers that pick up the sound emitted by the fish tags. They are not homebodies.

"We have found these fish can move 40 miles in a matter of just a few days," Garvey said. "They move quite a lot."

Garvey said he and other scientists still have a lot to learn about the pallid sturgeon. But the SIU professor said the pallid sturgeon, which eats smaller fish like minnows, is part of the river environment that is worth preserving.

mbliss@semissourian.com

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