Wildlife Officials Increase Efforts To Save Rare Fish

November 22, 2005

Release from: S. Heather Duncan
Macon Telegraph (Georgia)

TOOMSBORO - Swimming in a large plastic tank pulled behind Jimmy Evans' truck, the robust redhorse fish seem misnamed. They look ordinary enough: Fish mottled with a brown that almost forms stripes on their 6-inch bodies.

But 1,500 of the juvenile fish were stocked in the Oconee River at Ball's Ferry last week - three times more than were stocked there in the past 10 years combined - as scientists become more aggressive in their effort to save a species so rare and mysterious that it remained hidden for more than a century.

Evans, who coordinates the robust redhorse project in Georgia for the state Department of Natural Resources, pumped bottle-green river water into the big fish tank Thursday, allowing the fish to become accustomed to the new water temperature. Then he allowed them to drain out in a torrent. They clustered at the bottom of the boat ramp before flitting further into the river.

The robust redhorse got its name by being one of the largest fish in the redhorse family, with an average adult length of 25 inches. But the redhorse acts more like a squirrel than a horse. It swallows mussels whole, crunching their shells using teeth in the back of its throat.

The robust redhorse was little more than a legend between when it was identified in 1870 and when it was seen next - in 1991 during surveys for the relicensing of the Lake Sinclair Dam.

Instead of putting the fish on the endangered species list, which it qualifies for, federal wildlife officials created an unusual recovery program through public-private partnerships with power companies, states and universities.

New robust redhorse populations have been established in five rivers that were once part of their historic range, including the Ocmulgee, Ogeechee and Broad rivers in Georgia.

The result: For the first time this year, fish surveys found robust redhorse spawning in the Ocmulgee River near Lake Juliette, said Michael Abney, fisheries biologist for project partner Georgia Power. Evans estimates that 3,000 or 4,000 of the 10,000 stocked fish have survived in the Ocmulgee.

But in the Oconee between Milledgeville and Dublin, where one of only three wild populations survives, the robust redhorse seems to be dwindling. Its population is very old: Most adult fish there were born during the disco era. Scientists aren't sure why younger fish don't seem to be surviving.

Evans said there were probably 600 to 800 adults in the Oconee River when he rediscovered the species in the early 1990s. Only 10 were caught during this year's survey, and computer models estimate there are 140 altogether, he said.

"There's definitely a concern whether this method is working," Abney said. "We're not seeing the results we wanted to see."

It's possible the fish just aren't getting counted, said Cecil Jennings, research fishery biologist with U.S. Geologic Survey. They could be eluding the common counting method, using an electric shock to stun fish to the surface temporarily. Or scientists could be looking in the wrong places.

"They may have some kind of weird life history where they disappear and return as adults," Jennings said. His students at the University of Georgia built an artificial river and tested what habitats the robust redhorse prefer: fast, straight courses, eddies or other areas. It turns out that scientists may have been sampling in places the fish avoid, he said.

Many factors probably contribute to the rarity of the fish, Evans said. Soil erosion, both from current development and early farming in Georgia, washed into rivers and covered the gravelly bottom needed for the fish eggs.

Plus, the flathead catfish, introduced from the Mississippi River basin to Georgia, eats robust redhorse. And bottom-feeders such as mussels and the robust redhorse are very susceptible to pollution.

"The fish are an indicator species of environmental degradation," Evans said. "If you can preserve and protect and enhance your most endangered fish, then your other fish will do well."

There are no rules against catching robust redhorse, and sport fishermen have caught a few, Evans said.

The DNR increased its stocking efforts on the river this year. DNR officials find wild brood fish in the Oconee River in the spring, inject them with hormones and strip out the resulting eggs. The eggs are incubated at a hatchery during the summer, and the small fish are released in the fall.

Two female brood fish this year produced about 30,000 eggs, although many don't survive, Evans said. Each fish released is injected with a 1-millimeter wire tag with a microscopic identification number.

The history of the robust redhorse is full of contradictions. Evans said the fish, which once fed on native freshwater mussels that coated Piedmont river bottoms, now survive mostly by eating Asiatic mussels that have been destructive to other rivers and lakes across America.

Although Sinclair Dam causes fluctuations in water levels that can harm some fish, the robust redhorse would not have been rediscovered at all without research on the dam license, Evans said. The license includes rules that the dam can't interfere with normal river flows during the spawning season. The dam also catches eroded dirt.

Evans sees hopeful signs in the reappearance of long-lost species such as the robust redhorse and the ivory-billed woodpecker, which was found earlier this year in Arkansas.

"Despite what we've learned about our river systems, we've still got things to learn," Evans said.