RURAL FARGO – To John Dickleman, the tangle of branches and roots near a bend in the murky river looked a lot like a home for channel catfish.
It’d be a good setup for the fish, said the fishing guide from rural Moorhead, Minn. “You’re just chilling out in your office chair and it’s time to go eat, you slide out of your office and you go eat.”
Anglers have long known catfish like to rest in logs and holes where they don’t have to fight the current but are close enough to it that they can grab any morsel that flows past.
So that was where Dickleman put his bait, a big chunk of minnow.
He’d been reeling in catfish all evening though, in the low water of late June, he was having a hard time catching the feisty trophy fish that make for good Kodak moments.
For Dickleman and other anglers, the fascination with these thick-lipped whiskery creatures is where the big ones are hiding. And, increasingly, the Red River Valley has gained a reputation as home of some of the biggest channel cats around.
But, to those that study it, the fish is fascinating for so many other reasons.
In human terms, it is unfathomably ancient. According to the fossil record, the channel catfish, Ictalurus punctatus, has swam these waters unchanged for 17 million years, about 85 times as long as homo sapiens have roamed the earth. They long ago evolved the finest sense of taste among animals with backbones and their sense of smell is also among the keenest. They can live decades, and tests show they become among the smartest of freshwater fish as they age.
John Caprio, a biologist at Louisiana State University in Baton Rouge, first became enamored with the channel catfish in graduate school.
As a high school student in Virginia, he was already curious about how fish tasted and smelled. When he got to graduate school, it was natural for him to study channel cats, he said, because they are basically “swimming tongues with big noses.”
The catfish’s tastebuds aren’t much keener than those of other fish but a catfish’s whole body is covered in tastebuds, especially in the whiskers, or barbels, Caprio said. Its sense of taste is about a million times better than a human’s but it’s most sensitive to amino acids, the stuff that meat is made of, rather than sugar and salt.
All animals excrete the amino acids, including humans. When a person leaves a smudge on a glass, that smudge is full of the stuff, Caprio said. So, there’s a good chance the catfish Dickleman manhandled that June evening were tasting him and much more intensely than he knew.
Caprio also praised the catfish’s nose, which it uses to detect pheromones given off by others of its kind. The nose is key to a catfish’s social life. With it, one catfish can tell if the other is a female, if it’s ready to mate, how old it is and how capable it is in in a fight, among other things.
So important is smell to the catfish that nature has seen fit to grow its brain out under its nose where the two are as close as possible, he said, so when a catfish smells the brain knows about it almost right away.
Anglers sometimes try to get a channel cat’s attention by using bait that smells very strong, but that’s a mistake because it won’t always smell strong in water, Caprio said. When a human smells, he’s detecting chemicals that have vaporized and float in the air. When a catfish smells, it’s detecting chemicals that dissolve in water.
Caprio said he would bait with liver or cheese, which are high in amino acids that will dissolve in water.
Brad Durick, a fishing guide from downriver in Grand Forks, first became a student of the channel catfish a few years ago when he couldn’t figure out why they weren’t biting during summer floods.
“Water would go up 5 feet in a rainstorm and a week later it’d go down 5 feet then it’d go up and then it’d go down,” he said. “One day you’d be catching fish like crazy. The next day you wouldn’t.”
That launched him on a journey of discovery as he pored over river gauge data, weather records and even studies of catfish metabolism, comparing them with his own meticulous fishing journal. Eventually, he ended up writing a book, “Cracking the Channel Catfish Code,” followed by another one.
The first code he cracked, he said, was the why they didn’t bite when water levels went up. It’s because after a storm, the water gets really muddy from runoff, which the fish don’t like, he said. They’ll hunker down and wait for it to pass, he said.
His most recent discovery was why catfish bite a lot in the days before a storm and stop just as the wind shifts. He said noticed how the barometric pressure dropped before a storm and theorized that when the fish sense that it knows bad weather is coming that could make it hard to feed, perhaps because of muddy runoff. So they feed a lot before it arrives and hole up when it does.
Scientists who study channel cats have observed how adaptive they can be.
In one 1985 experiment, biologists in Wisconsin and Missouri tested 16 kinds of freshwater fish to see how quickly they learned to avoid a light that precedes a mild electrical shock. Channel catfish were among the fastest learners, and the oldest of them eventually had a 100 percent record. They even remembered the experiment more than a month later when they were tested again.
Among the dumbest of fish? The northern pike, which didn’t manage to figure it out more than a third of the time.
Long before anglers came to wrestle them out of the water, channel catfish have lived in this part of the world.
In the 1960s, paleontologists found in southwest South Dakota a fossil of a fish that appeared identical to modern channel catfish. That fossil dates back to the middle Miocene, when the Red River Valley was still a parched land of rolling hills where camels, three-toed horses and hyena-like dogs roamed. The Missouri River still flowed north along with nearly all rivers in the Dakotas, emptying near Greenland.
Channel catfish as a species have watched glaciers advance and retreat more than a dozen times and witnessed the prairie turn to forest and back just as many times before the first man came along to catch them.
Today, channel cats are among the most plentiful species in the Red River. Surveys by the Minnesota Department of Natural Resources found they outnumber all other fish in the stretch between Breckenridge and Grand Forks. They aren’t as numerous compared to other fish farther north. But there, where the river widens and the water is deeper, they are older and bigger.
Jamison Wendel, a DNR biologist, said it’s probably because wider, deeper waters can support more small fish that bigger catfish feed on but have fewer of the nooks and crannies that smaller catfish need to hide in.
As they grow larger, few other animals will prey on them. So older fish can grow truly large. Counting rings in the spine of captured catfish, the DNR found that they can be older than 20 years and grow longer than three feet.
That’s not much comfort to Dickleman, who was already struggling with the low waters north of Fargo. Going into July, he said he expected the fishing to get even slower.
It was close to their time to spawn, when channel cats look for mates upstream where the narrow river with more nooks and crannies favors their young. Radio tagging by biologists have shown they’ll migrate hundreds of miles up and down the river’s 550 miles in spite of dams in Drayton, N.D., and Lockport, Manitoba.
When they do mate, the male catfish won’t be going anywhere, to the frustration of anglers. They’ll stay on their nest, fanning their eggs to keep them aerated and guarding them from other fish keen for a meal.
Downstream, Durick wasn’t having much luck either.
He’s got a lot of spreadsheets and lots of records, but sometimes the channel cats still flummox him, he said in late June. “Just when you think you have these fish figured out they prove you stupid – and they still do. Last week, I struggled. The week before I killed them.”
The channel catfish still has a few mysteries left.