One of Georgia's biggest gamefish is getting even bigger in Thurmond Lake.
A survey conducted every four years -- and completed last week -- found more flathead catfish than ever before, including a 47-pound specimen.
"We found flatheads in previous surveys four years ago, but we saw more bigger fish this year," said Ed Bettross, a Georgia department of Natural Resources fisheries biologist.
The study involves using the chemical rotenone to kill fish in three selected areas at the 70,000-acre lake. The fish are then retrieved, counted, measured and studied.
Flatheads are native to some Georgia river basins and are well known in Thurmond Lake.
However, the fish has become controversial in south Georgia rivers -- such as the Altamaha -- where flatheads introduced by accident have decimated bluegill and bullhead catfish populations.
Mr. Bettross said the giant fish are not perceived as a problem at Thurmond. "They're a good alternative for fishermen. As far as chewing up bluegill, we don't see them as a danger to that resource."
The rotenone survey four years ago yielded flatheads in the study areas at a density of 5.5 kilograms per hectare. This year's study found a much denser concentration: 20.3 kilos per hectare.
Mr. Bettross said the fish appear to be getting larger, but likely not more prevalent. The 47-pound fish retrieved during the survey likely "weighted" the results somewhat, he added.
Thurmond Lake has held Georgia's record for flatheads several times in the past. However, a 63-pound, 8-ounce, specimen caught this summer in the Altamaha River is the current record holder, he said.
The survey was conducted in coves in the Bobby Brown State Park, Murray Creek and Mistletoe State Park areas of the lake.
Another unusual species turning up in Georgia -- first at Lake Lanier near Atlanta, and then at Thurmond Lake -- is the South American pacu.
"They look like piranhas, but they're not," said Reggie Weaver, the state's Gainesville District fisheries biologist. "They eat mainly berries, nuts and plants. But they don't bother people."
"At Lake Lanier, we're close to the metro Atlanta area where all the people are. We think they're turned loose."
Similarly, Thurmond Lake is in close proximity to Georgia's second-largest metro area: Augusta.
"We have anecdotal evidence they're turning up in Thurmond Lake," said Corps spokesman Jim Parker.
Farther upstream, confirmed pacu catches have occurred in Lake Hartwell, which feeds Lake Russell and empties into Thurmond Lake. The fish average two pounds, but can reach four or five pounds.
"They don't tolerate cold water well, so we don't believe they're reproducing or creating any kind of resident population," Mr. Parker said.
The fish have also turned up in Lake Notley in north Georgia; and most recently at the Charlie Elliott Wildlife Center in Jasper and Newton counties, where a pacu was caught last week, said DNR spokeswoman Beth Brown.