Down at the bottom of that dirty ol’ riverDown where the reeds and the catfish playThere lies a dream as soft as the waterThere lies a bluebird that’s flown awayThere lies a bluebird that’s flown away–Catfish song, Townes Van Zandt.
The channel catfish is a wide-ranging species with a distribution from the Hudson Bay region of Canada, south to Florida and northern Mexico, north through New Mexico, Colorado, and Montana, and upward into southern Manitoba. It also has been introduced into a number of North American drainages outside of its native range. It was first described from the Ohio River in 1818 by Rafinesque, who christened it Silurus punctatus. The current scientific name Ictalurus comes from the Greek ichtys for fish and ailourous for cat; and punctatus for little spots – referring to the dark spots along the side of the body. While not native to WA/OR they have been stocked for sport – https://www.youtube.com/watch?v=ewPWnGYG–U&feature=player_embedded
These are pretty dang versatile fish. They prefer warm water (averaging 70 degrees F) and are found in rivers, reservoirs, streams, lakes, backwaters, swamps, and oxbow lakes. They also can be found in the upper extent of estuaries and tolerate salinity as high as 19 – 21 parts per thousand. So, as you likely know, the higher the water temperature the less its capacity to hold oxygen. And catfish, as a group, seem to readily adapt to warmer water and manage to occupy habitats intolerable to other fish species. They will change their behavior with streamflow and temperature – seeking out deeper cooler water during summer extremes.
When I worked as a fisheries biologist on the Susquehanna River back east, part of our work was implanting radio transmitters in a number of fish species, including channel cats, and investigating how they reacted to different flow regimes of the river’s hydroelectric facilities. Sure as shootin’ during the summer they would beeline to deep pools, below the cold water dam releases, at the outlets of streams, or would retreat to the upper reaches of the Chesapeake Bay. Oddly, somehow, the catfish were able to expel the small transmitters from their bodies that we surgically implanted in their body cavity under anesthesia within a year or so, while other fish we tracked for up to three years.
Spawning occurs from May through July when water temperatures reach about 75 degrees F. Nests are located in weedy shallows, under rock ledges, and in tunnels within turf banks. A colleague who once worked in a commercial catfish aquaculture operation told me that what worked best for mating catfish was a 20 gallon milking tin with rocks in it to keep it on the bottom of the pond and the catfish loved this little manufactured cave for nests. Males will prepare a nest site by fanning it with his fins. There is a spawning hierarchy with the oldest and biggest fish spawning first. Spawning lasts 4-6 hours and females will lay 2,000 – 70,000 eggs. The males fertilize the eggs and then guard the nest – including keeping away the female, who will eat her own eggs. Incubation lasts 5-10 days and the young remain in the nest for about 7 days. They feed on midge and caddis larvae and a wide array of small aquatic invertebrates. Once they reach about 4 inches they are omnivorous. There is a distinct inverse relationship to size of catfish and the sharpness of their pectoral and dorsal spines – more on this later.
Adults are fast and powerful and feed on small fish, crayfish, mollusks, insect larvae, and almost anything that swims in front of them. Adults have an elongated body that is compressed posteriorly, with small eyes and a mouth that opens beneath its snout. It has eight “whiskers” around the mouth – four on the chin, two on the snout, and one on both corners of the mouth. The tail is distinctively forked. Adults average 15 – 24 inches with a maximum of 52 inches. The highest recorded weight is 58 lbs and the maximum recorded age is 15 years. Sexual maturity is reached at 2-6 years. Channel catfish growth curves – the relationship between length and weight – is rather steep, indicating that as they get longer they proportionally get fatter quicker.
Two of our men last night caught nine catfish that would together weigh three hundred pounds. The large catfish are caught in the Missouri with hook and line. Patrick Gass, September 25th, 1804, Voyage of Discovery.
Channel cats are an important and popular game fish throughout their range. Most folks catch them via hook and line, but noodling, our catching them by hand is popular in some areas. Under this method one sticks their hand into crevices under banks and such, and offers wiggling fingers as bait – when the catfish latches on you just pull him up! When we were looking for large catfish for transmitter subjects, we would jet down to the Susquehanna Flats, the upper, shallow reaches of the Chesapeake and seek out the commercial catfisher boats. After a quick negotiation we would exchange dollars for a group of big catfish to take back to the lab for surgery, transmitter insertion, and eventual release and tracking. All in the name of science.
Handling large catfish can be a trick. They are a bit slimy because they don’t have scales but a tough skin kept slick by mucous. I would bring home a stringer full and my Mom would point me to the backyard where I’d skin them and then Mom would work her magic on them with a frying pan. If handling a large cat to measure him, for instance, the best strategy is to pick them up off a surface and crook their tail, which somehow pinches a major nerve and they just relax and are much more cooperative.
Catfish will communicate by sound using a couple different mechanisms – stridulation and drumming. Stridulation produces sound by the grinding of bony parts of the pectoral fins and pectoral girdle while drumming creates sound from the contraction of specialized muscles and reverberation through the swim bladder. Here are some locals explaining how to avoid the spines. https://www.youtube.com/watch?v=2LAxVccKGFs
I don’t have a good answer for the small, young-of-the-year cats. Their spines are amazingly sharp and barbed – oh – and full of fish mucous, so when you inevitably get poked by handling them the puncture is sure to get infected, leaving your hands like pin cushions by the end of the field season. One of the dreaded duties as a fish tech was reservoir trawl samples in the early autumn when you were sure to bring up a tangled ball of several thousand young catfish in the net, and then had to pull them all apart and estimate their density. We would stand on the back of the trawl boat watching the net get pulled in – please, oh please, don’t be full of young catfish! It inevitably would be and you would bear down on the tedious task of counting hundreds of small catfish – all scared and thus flaring their spines and waiting to poke you. Looking at a ball of spiny little catfish as big as a beach volley ball tangled in a net can be quite depressing.
I distinctly remember taking a civil service exam on the 34th floor of World Trade Center #2 for a New York State biologist position, filling out the little circles of the multiple choice test and studiously avoiding placing my index finger on the pencil because the tip was so sore from a catfish spine puncture. Later that week when back at work, I looked closer at my red and swollen fingertip under a dissecting scope and noticed a small shiny element. With tweezers I pulled out an inch long broken catfish spine, apparently embedded in there for a couple of weeks. No wonder it hurt.