Catfish are one of the few fish that can communicate using a special organ called the Weberian apparatus, which is an important feature in their survival. They are able to communicate by two different types of sounds they can make, drumming sounds and stridulation sounds. In fact, this fish is an expert in making noises and also hearing other sounds. After more research humans also found out that catfish of all ages can hear and interrupt the sound, as before it was thought that only the older and mature fish could make this noise.
Noise that catfish make
The way we communicate with each other for us humans is by speaking or writing. We have many languages through which we talk to people; however, it is not the same for other animals. Animals usually make different noises to communicate with their own species that humans do not understand.
Just like this, catfish make noise that can’t be interrupted by humans. Catfish usually make a squeaking noise that some people say sounds a little like a cat purring, hence one of the reasons for the name of the fish, along with the whiskers or barbels they have. Catfish can produce a lot of different noises, and all of them fall into two categories, drumming sounds and stridulation sounds which they use to communicate. Both of these ways of producing sound are very important in their survival.
Drumming sounds
The first way of communication of catfish is the drumming sounds that the fish makes. As the name suggests, this is a sound like drumming your fingers on a desk or some surface. For the drumming noise, the catfish uses its swim bladder that many other fish that can communicate used to communicate, as well. They use an indirect vibration mechanism while using the swim bladder, and it has a simple mechanism through which it produces noise.
There is a muscle called the sonic muscle, which is present in fish that can make noise. The sonic muscle is inserted on an elastic spring (ramus Mulleri), and when the sonic muscle pulls the elastic spring forward, the fish’s swim bladder extends. Since the elastic spring has tension, when the sonic muscle relaxes, the swim bladder returns to its original position when the sonic muscle relaxes. When this mechanism happens, the drumming sound is produced.
Stridulation sounds
This is another important mechanism in the catfish that is used to make noise. This is more of a unique feature that most fish don’t use. However, other animals have been observed making sounds using stridulation like crickets. Some fish use their swim bladder to enhance the stridulation sounds produced as well.
Stridulation makes squeaking noises in catfish within the range of 1000 Hz to 4000 Hz. The catfish has specialized pectoral fin spines that make this squeaking noise. The pectoral fins in the fish have a modified base, as the dorsal process part of the fin looks like a ridged potato chip. The enhanced first pectoral-fin ray is called a spine.
The spine of the fin can be moved by abductor and adductor muscles, and when the catfish makes noises, the sequence of ridges at the base of the catfish’s spine rub against the pelvic girdle. This creates a series of short pulses. Another easier way to understand the mechanism is to remember that the dorsal process of the pectoral fin is rubbed against the pectoral girdle to make these noises. So, when the pectoral fins are moved quickly, two hard and bony areas rub against each other, which results in the sound.
To understand the sound better, move your finger down the teeth of a comb; doesn’t it make a series of harp taps? This is the noise that the catfish and some other fish can make using the stridulation process.
Uses of making sound in catfish
Unlike humans, catfish and other animals don’t just make noise because they want to talk. There is a purpose for them making these noises, usually to attract prey and potential mates. However, there can be some other reasons for this as well.
The biggest reason is to ward off predators. These noises are to warn the predator that they are here, usually made when they are protecting their eggs. The catfish croaks like a dog barks because it is scared. This is why a lot of fishermen hear the catfish making this noise once it is caught. This croaking sound heard is the stridulation noise made by the fish.
Moreover, when in distress, the fish makes more noise, but it is also produced during competition with other catfish. In fact, the fish can make noise whenever it feels like it, and sometimes they do that. Chances are, whenever the fish is swimming, you will hear it make noise, which is more noticeable in some species of catfish compared to others.
Factors affecting the sounds made by catfish
The truth is, not all catfish can produce the same intensity and amount of noise. In fact, the different sexes of the same species of catfish also produce sounds of varying intensity. The fish is also smart enough to differentiate between sounds of different pitches and velocities. If that wasn’t enough, this smart fish could also know the distance of the sound and which direction it is coming from!
The sound is different depending on its function; if it is in distress, it might be louder than if it is for some smaller reason. Moreover, the drumming sound is not as loud as stridulation noise, so the intensity will change according to the mechanism they are using as well. Another factor is the species of fish; some species make louder noises while the others don’t. Some species of catfish can only use one mechanism to make a sound while others can use both, and some catfish can’t even make noise, which is due to evolution.
Other physiological differences also affect the sound produced. The bigger the fish, the more sound it can produce. Furthermore, the younger catfish cannot make as loud of noise as a mature catfish, so as the fish gets older, it makes a louder noise for a longer duration. The younger fish are usually only able to communicate small distances.
In conclusion, catfish are one of the most interesting fish that can make noises in two ways. They use this ability to warn predators and communicate with other underwater fish. You might be able to hear them talking if you pay attention. Now you know the exact mechanism they use to make noise as well, which will help you understand which mechanism the catfish you have is using to communicate!
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