Originally created 05/29/99

Biologists cultivate rare fish

For almost a week, Greg Looney and Brian Estes have operated a makeshift maternity ward on the banks of the Savannah River.

Soon, they hope there will be cause for celebration.

"We've had lots of curious people come by," said Mr. Looney, a U.S. Fish & Wildlife Service biologist working to resurrect a shrinking population of one of the continent's rarest fish.

The robust redhorse sucker, named for its stout shape, was first discovered in 1870. But its absence over the next century led scientists to believe the fish had followed the dodo bird and passenger pigeon into extinction.

Ichthyologists were stunned when -- in 1991 -- an unusual fish hoisted from the Oconee River near Dublin, Ga., was identified as a redhorse sucker. And 18 months ago, a single specimen turned up in the Savannah River.

"That was our first clue they were in the Savannah," Mr. Looney said. "The Oconee River was the only known population until now."

This week, Mr. Looney and Mr. Estes set up camp along the Savannah's rocky shoals south of Interstate 20 near Augusta Canal.

"These fish have to have gravel bottoms to spawn, so this was the likely area to look for them," Mr. Estes said. "And we found them."

Using electric shocking devices to stun the fish, the biologists captured four females and 15 males that were kept in holding tanks fed by portable oxygenation systems and fresh water pumps.

"We've caught so few that we have no idea what the river's population is," Mr. Looney said. "But what's important is to find out whether it's a self-sustaining population."

The Oconee River group, he said, numbers more than 1,000 fish. But studies have found little evidence they are reproducing.

"We've gotten eggs and sperm there, but since we started studying them in 1991, less than a dozen fish have turned up that we consider to be juveniles," he said. Most specimens are from 11 to 26 years old.

The problem in the Oconee is water levels that fluctuate six to eight feet, often drying out or washing away larvae and eggs. Siltation is also a problem, as is the decline of small shellfish preferred by the rare fish.

The Savannah River, with its less drastic water fluctuations and clean, oxygenated rapids with lots of gravel bottom, offers perhaps the best opportunity to help the robust redhorse recover.

The captured fish are anesthetized, injected with a labor-inducing hormone, drained of their round, lemon-yellow eggs and released into the fast-flowing shoals from which they were taken.

The eggs will be taken to several sites for hatching, including the U.S. Fish & Wildlife Service Fish Technology Center in Warm Springs, Ga., and the Georgia fish hatchery in McDuffie County.

If hatched successfully, the young will be used to help restock the fish's native waters in the Savannah and elsewhere.

Robert Pavey covers environmental issues for The Augusta Chronicle. He can be reached at 868-1222, Ext. 119, or rpavey@augustachronicle.com.


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