JORDAN LAKE -- It's too late to stop flathead catfish from eventually dominating the food chain of this Triangle lake.
But state fish biologists are trying to learn all they can about the flatheads swimming around Jordan Lake before the aggressive cats take over.
It's anybody's guess about how long the fish, which are not native to river systems on this side of the Appalachian Mountains, have been in the lake, but the earliest official record of a flathead in Jordan is 2004. On Internet message boards, there are claims of catches from the late 1990s.
Time is of importance because flathead catfish can fully establish their dominance in as little as 10 to 15 years.
Although that may be good news for catfish enthusiasts, that will likely spell trouble for the lake's populations of largemouth bass, crappie and striped bass, according to biologists such as Corey Oakley, a district fisheries biologist for the N.C. Wildlife Resources Commission.
Collecting data
Oakley and his colleagues with the commission began hunting flatheads on Jordan Lake this year, hoping to find out, among other things, just what the fish are eating.
On a recent morning, Oakley and assistant fisheries biologist Jessica Baumann returned to the lake a day after setting lines out with live shad and sunfish in the hopes of catching a flathead.
The lines were similar to the trot lines often used by commercial catfish fishermen, using nylon rope attached to a floating jug or tethered to the shore to set several hooks per run.
At the first line of the morning, the jug wiggled away from the boat as it approached.
"What are you?" Baumann asked, before bringing the line in hand-over-hand, only to be disappointed at the sight of a 10-pound channel catfish.
The lines hooked several catfish on this morning, just no flatheads. Most were channel catfish, though there were a few white catfish, a native species that's also likely to be adversely affected by the arrival of flatheads, Oakley said.
"That's one of the things we're trying to figure out: where they are," Oakley said. "We know they're in here."
If not being able to find them is a good sign, the biologists also found a bad sign recently when they shocked up a juvenile flathead with electro-shocking equipment, a sure sign that the fish are reproducing successfully in the lake. Earlier this year, the biologists shocked up an 18-pounder that was full of eggs.
No bottom feeder
It was catfish fishermen who most likely illegally introduced the catfish to the lake, Oakley said.
Flatheads have been in the Cape Fear River since the 1960s, when the state accidentally stocked 11 flatheads into the river.
As a game fish, flatheads are sought after by a niche group of fishermen for their size, fight and brute strength. They can grow to 120 pounds and are native to the Mississippi River basin.
The thing about flatheads is that they are not bottom feeders like the state's the other catfish species, such as channel, blue and white. Flatheads eat only other live fish.
Flatheads not only eat other game fish, but they also compete for the same food, said flathead expert Tom Kwak, a professor at the U.S. Geological Survey's co-operative fish and wildlife research unit at N.C. State.
"While they do eat largemouth bass, they're also eating the largemouth bass food supply," Kwak said in a telephone interview. "When those are combined, they can reduce another species by 50 percent. ... They're such perfect predators."
Kwak said the fish, after introduction, typically take longer to establish dominance in a reservoir system than in a river.
"In a river, it takes a smaller number of fish to get to the higher densities where we're catching them easily," he said.
A 'domestic' invasive
Kwak finds it ironic that most fishermen don't seem to care about this domestic invasive species. When foreign exotic species such as Asian carp and snakeheads show up in American waterways, there is outrage.
"If a thing comes from Europe or Asia, everybody gets all nervous about it, but if it comes from the other side of the mountain, it's OK," he said. "Their effects are just as damaging."
Native fish such as the red-breast sunfish, which looks like a bluegill, have already taken a major hit in the state's coastal rivers.
"It's important to North Carolina heritage," Kwak said. "A family will go to a bridge and catch this beautiful panfish. By adding the catfish to a river, there's a large cost."
Oakley agreed.
"If you add something, you usually have to give up something," he said.
Just as concerning to Kwak is that few of these fish are taken home for the table in this part of the country. In their native Midwest, flathead fishermen think nothing of taking one home, but here, catfish anglers seem to be practicing catch-and-release.
"That allows them to build up to a high number," he said. "If we harvested flathead catfish at the same rate they do in the Midwest, our native fish would be at much higher levels. Our native fish would feel some relief."
In the meantime, Oakley will continue to collect data on the flatheads in Jordan.
He's hopeful that there will be enough food to go around in the lake, famous for bass and crappie.
"Maybe it can handle it, maybe not," he said. "They usually become the apex predator. It may be a decade before we really see."
