They seem to get bigger and bigger -- even if we don't want them to. Last week, Georgia authorities weighed in a flathead catfish from the Ocmulgee River that weighed 103 pounds -- eclipsing the known state record by more than 20 pounds.
The angler -- 76-year-old Tom Head -- won't be able to claim the title, though, because he was using setlines and a floating jug, and not rod and reel, as recordbook entries require. But it was still a huge fish.
Locally, these giant cats already live in parts of the Savannah River Basin, including Thurmond Lake, where 50-pounders have become relatively common, said Matt Thomas, assistant chief of fisheries for Georgia's Wildlife Resources Division.
The huge predators -- whose native range in Georgia includes only the extreme northwest corner of the state -- have infiltrated other river systems, including the Ocmulgee, Satilla and Altamaha, where they have drastically reduced populations of native fish such as sunfish and redbreast.
"Typically, they cause the most problems in river systems, but in reservoirs, they don't seem to cause as much damage," he said.
Fisheries biologists have long been aware of their presence in Thurmond Lake, but so far have not confirmed their existence in the lower river, although anecdotal reports from fishermen indicate they may indeed be there.
Head's giant cat was 57 inches long and 41 inches in circumference around its belly. He used a tarpon hook and a half-pound bluegill for bait.
Thomas said flatheads are easily caught on rod and reel. They are most active at dawn and dusk, seek out rocky ledges and cover during the day and will move to shallow sandbars and shoals at dusk. They almost always prefer live bait -- the larger the better.
STRIPERS DYING: It's been a tough two weeks for one of Thurmond Lake's most popular sportfish.
Layers of oxygen-depleted water far beneath the lake's surface are believed to be responsible for killing more than 1,300 mostly adult stripers recovered by biologists who say the problem doesn't appear to be getting any better.
This year, because heavy rains refilled the drought-stricken lake so rapidly, the oxygenated layers are deeper than usual. When the limited oxygen in those layers dissipates, the fish trapped in the "bubble" are asphyxiated and die.
The problem area is confined to the area within a mile of Thurmond Dam, where stripers pursue blueback herring this time of year. Both species seek out cooler water.
Recent monitoring has detected oxygen levels as low as zero to 1 parts per million more than 20 feet below the surface behind the dam. When levels drop below 2 parts per million, it begins to kill the larger fish.
Jamie Sikes, the corps' fisheries biologist, said fish kills involving baitfish are fairly common at the lake, but this year's development is unprecedented.
By 2010 or 2011, oxygen issues at the lower end of the lake could be much improved because of an $11.3 million cryogenic oxygenation system that is under construction near Modoc.
Once completed, the oxygen plant will pump 20 tons to 100 tons of liquid oxygen per day through seven miles of perforated pipes submerged 80-90 feet below the lake's surface.
Although the project will be almost invisible to visitors, its impact will come in the form of a swath of highly oxygenated water that will lure and hold sportfish -- and fishermen -- during the hot summer months.
Reach Rob Pavey at 868-1222, ext. 119 or rob.pavey@augustachronicle.com.
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