Catfish are extraordinary specimens – and I don't just mean when they're breaded and deep fried. They have remarkable sensory abilities, making them the most keen and perceptive fish in the water. Much like us, they use their senses to navigate their way around their watery world. And knowledge of how a catfish's senses work can help you out a lot when you're trying to catch one.
We'll start with their hearing. Obviously catfish don't have visible ears (although that would be a sight to see!). That doesn't indicate, however, that their sense of hearing is less than sharp. A catfish's hearing begins in its swim bladder. When sound waves travel through the water, they penetrate right through the catfish, and its swim bladder begins to vibrate in the same way that our eardrums do when we hear a sound. The sound waves are heightened by the swim bladder, whose vibrations carry those waves to small bones in the inner ear – called otoliths – which also start vibrating. The pulsations of the otoliths bend small hair-like projections on the cells beneath them, which in turn send sound messages to the catfish's brain. Pretty high-tech for a lowly fish, huh? Well it gets even more amazing. In most fish, the swim bladder and the inner ear aren't connected; catfish, however, have a series of bones called the Weberian apparatus that connects the two. Consequently, their hearing is infinitely better than that of other fish. They can hear very high-frequency sounds, about 13,000 cycles per second, whereas fish that lack the Weberian apparatus can hear frequencies ranging only from 20 to about 1,000 cycles per second. Big difference! This is why farm-raised catfish seem to know when their feeder is approaching; they can hear footsteps from far away. The lesson to be learned here is that catfish can hear you clearly, so be as noiseless as possible!
Compared to its other super-senses, a catfish's eyesight is probably the least effective. However, this doesn't mean that catfish can't see! They can see in color, and in differing degrees of light and darkness. In clear waters, their eyesight is their primary means of spotting and catching food. Vision is also sited as the number one fright-causing sense; if a catfish sees something that looks suspicious, such as a shadow or silhouette cast over the surface of the water, it will hide or flee and refuse to return until the trigger of its fear is gone. Cat-fishing at night can lessen the chance of inadvertently scaring them away with shadows.
Imagine being able to taste a piece of food just by touching it. That's exactly what a catfish can do! Their sense of taste is highly developed. A human tongue has about ten thousand taste buds, while a catfish – even one that's a mere six inches long – has about a quarter of a million! You can't touch a catfish without touching taste buds; they're located everywhere on its body. There are large concentrations of taste buds in the mouth and gills, but also down the fish's sides, back, belly, fins, and even its tail! These help the fish to locate food even in dark or muddy waters. The largest concentration of taste buds is on the whiskers (technically known as "barbels"). A catfish uses these as feelers, allowing it to sample a little taste of something without having to get too close to it. If the taste on the whiskers tells the fish that the item is edible, it has found its dinner.
A catfish's "nose" is actually behind its upper jaw. And it's not actually a nose; it's just two olfactory pits. Each pit contains a nostril for incoming and a nostril for outgoing water, and each nostril is lined with folds of ultra-sensitive tissue. To give you an idea of just how sharp a catfish's sense of smell is, consider this: the more folds a fish has in its olfactory pits, the better its ability to smell. Catfish have an excess of one hundred and forty folds, while other fish have eight to twenty. Water flows over these folds and allow detection of certain substances. It is because of this ability to smell that many fishermen believe that stinky bait is the way to go when catching catfish, but this isn't necessarily true; catfish detect chemical compounds in the water – they don't smell what we're smelling when we sniff stink bait, which are the chemicals reacting to the air.
As if you weren't already amazed by the sensory abilities of the catfish, I've saved the best for last: electroreception. In the same way that sharks hone in on their prey, catfish use an electric sense to find food. A catfish's head and lateral line are clustered with special pores that lead directly to electric sensory receptors. When the fish is within a few centimeters of a possible food source, its electroreception can help it zero in on its quarry. It is electroreception that allows a catfish to dig in the mud to find worms, larvae and other tasty treats.
So now you know. Catfish are living, breathing, swimming sensory phenomena. Their remarkable perceptions help them tremendously. And keeping all that in mind can help you, too. Happy fishing!
