August 17, 2021
By Keith Sutton
It might be nice if our big rivers had remained all-natural like they were 150 years ago, but such is not the case. Agencies like the U.S. Army Corps of Engineers and the Tennessee Valley Authority have tamed the waterways where barges now transport commodities such as grain and coal. In the process, they created thousands of structures from rock, concrete and steel to help reduce flooding and erosion while making it safer and easier for these massive boats to travel.
Learning how catfish and their forage species relate to these structures is imperative for anglers hoping to catch the blue cats, flatheads and channel cats lurking in these waters.
Most catfish anglers know that big cats often swim in the churning tailwaters just downstream from big-river dams. Catfish arrive here in the spring during upstream spawning migrations. Because foods such as shad, herring, crayfish and carp are plentiful, the catfish stay here to gorge on the bounty throughout summer.
Oxygen content, current velocity and forage abundance reach their highest levels in the whitewater immediately below each dam, creating conditions catfish love. As spawning migrations progress, catfish crowd into the food-rich water in ever-increasing numbers, with larger fish laying claim to the best feeding locations.
Many catfish hold in narrow "grooves" of slower-moving water between gates in the dam or created by pylons in front of the gates. Current slackens in these grooves, enabling catfish to feed without being swept downstream. Therefore, dropping a baited rig into a groove will often lead to a hook-up.
Bite-sized pieces of cut-bait are perfect enticements here. Slice a shad, herring or other oily-fleshed baitfish into 1-inch chunks (anything larger tends to spin in the current, creating tangles). Push the hook all the way through the bait, leaving the barb exposed to ensure penetration when you set the hook.
A three-way rig incorporating a 6/0 to 8/0 Kahle hook and 4- to 8-ounce bell, bank or pyramid sinker works great in this situation. Tie your main line, typically 50-pound-test PowerPro Spectra or other braided line, to one eye of a three-way swivel. Add leaders of monofilament or fluorocarbon line—one 18 inches long and one 24 inches long—to the other two swivel eyes. Tie the hook to the longer leader and the sinker to the shorter one. The sinker should be just heavy enough that the current drags it slowly across the bottom.
Cast into the upstream end of a groove and allow the rig to sink. It should go straight to the bottom if you hit the groove properly. If you miss, you'll feel the rig tumbling downstream. Practice enables you to hit the sweet spot and know what’s happening.
When you hit a groove, allow the rig to remain in one spot for several minutes. Cats swim from one end of the cone-shaped groove to the other repeatedly. The grooves usually are less than 100 feet long, so a catfish should quickly find your bait. Its strike will be hard and unmistakable.
If cats quit biting in one groove, reposition your baited rig in another groove and try again. Water flow through a dam increases or decreases as power requirements or water levels demand. So, even though water runs continuously, the flow may change several times daily. When the flow changes, cats often move to find more slack water in which to feed.
HIT THE WASHOUTS
The washout hole is another important catfishing area below a dam. This is a river-bottom depression scoured by the forceful action of water releases. It usually starts near the downstream face of the dam and stretches several yards.
If you can do so safely, use sonar to pinpoint the hole's downstream lip, as that's where most catfish hold. The lip appears as a sharp drop that's discernible as you move toward the dam. If the washout hole is within the danger zone off limits to boaters, you'll have to speculate on its position and fish it from a distance, if at all.
Because it has few components to snag on bottom structure, a jighead/cut bait combo is excellent for fishing washouts. Impale a small chunk of cut bait on a jighead, leaving the hook point exposed. Use a jighead heavy enough that you can fish it vertically beside your boat. This may require saltwater jigheads weighing 2 to 3 ounces or more. Be sure hook points are honed to needle sharpness.
Motor upstream as far as safety permits, then drop the baited jig to the bottom and crank it up a foot. As your boat drifts, use your motor to maintain a speed that keeps your bait directly below you. When you reach the washout's downstream lip, the bait will move up the drop and drag behind the boat. This is when most strikes occur. If you get one, that's great. If not, continue drifting until you're on the shelf below the hole, then reel up your rig, motor upstream and drift through again.
Constant water flow through the dam is necessary to maintain good catfishing conditions immediately below the dam. Should conditions exist that force dam operators to close all gates, catfishing success will nosedive until ample water flow is restored. The best catfishing generally coincides with periods of moderate to high water flow.
When catfishing in large navigable waterways, it pays to study and understand the long narrow rock walls known as wing dikes or wing dams. These catfish-attracting structures are placed in strategic locations to help maintain ship-channel depth and lessen shoreline erosion. They are most numerous in hydropower and navigation dam tailwaters but may be scattered along the entire length of a big river.
Wing dikes fulfill their intended functions by diverting current. They usually are built perpendicular to the shore; when moving water strikes one, it swirls back on itself.
The force of the current then moves outward toward the middle of the river. The water velocity slows, allowing suspended sediments to fall and accumulate on the river bottom.
Over a period of years, the spaces between wing dikes will fill with these sediments. This narrows the river, creating more forceful current in the main channel that sweeps the bottom clean so little dredging is needed to maintain adequate depth for barge traffic. Inactive catfish typically stay on the downstream side of a wing dike, lying on the bottom, usually near inshore reaches. Current is minimal here, so rest is possible.
Most feeding catfish, especially the more numerous small cats, hold near the river’s bottom on a wing dike’s upstream side. The reason for this is three-fold.
First, water hydraulics here create a "tube" of reduced current near bottom that runs the length of the dike. Hungry cats can hold and feed here without expending much energy.
Second, this is an area of abundant food, with crayfish and mussels in the rocks, and shad, herring and other baitfish holding in the slower cylinder of water.
Finally, when the river is high and the wing dike is submerged, catfish can feed on addled or injured forage species easily captured in the boil line directly above the rocks and immediately downstream.
You should now understand the basics of catfishing around wing dikes: To catch lots of cats, fish the upstream side. Downstream is rarely as productive. There is another lesson, however, that's perhaps even more important: Trophy-class cats are best targeted in eddies near the ends of wing dikes.
An eddy is a circular hydraulic created when current bounces off the point of the rocks. These maelstroms sometimes are called "whirlpools" or "suck holes." They are readily visible, and because they are the prime feeding sites along wing dikes, they tend to harbor bigger, more dominant catfish. Active catfish are usually near the eddy's edge, lying on or near bottom in the hole beneath, which is created by the swirling water.
A three-way rig is ideal for catching them (and also works well along other portions of a wing dike). A 2-foot-long hook leader the same pound-test as your main line (again, 50-pound-test braided line is the most common choice) is tipped with a 6/0 to 12/0 circle hook. The 12-inch weight leader (of lighter line than your main line) is tied to a 3-ounce bank sinker. Both leaders are tied to separate eyes of a three-way swivel, with the main line tied to the remaining eye. Cut shad or herring is preferred by blues and channel cats, while big live baitfish are the ticket for flatheads.
Anchor your boat well back from the eddy you intend to fish, then cast to the edge of the whirlpool. It would seem that a bait positioned in this way would swirl around and around. But, when done properly, it will sink quickly to the bottom and remain stationary. Reposition your rig if necessary to achieve this end, then prepare for the rod-jarring strike that will soon follow if a giant catfish lurks nearby.
Often, big cats cruise slowly through a hole, waiting for something to jolt their taste buds before they move in. Allow the bait to sit up to 10 minutes, but if there’s no bite by then, move and try another eddy hole. Strikes usually come quick and hard, so use heavy tackle and keep a firm grip on your rod at all times so as not to miss a shot at a trophy.