The catfish is a large and menacing looking, but usually harmless to humans fish. They live solitary on the river bottom and rarely appear near the surface, lazy and slow, but during the hunt they are able to accelerate sharply. Fishing for catfish is very popular, because they have delicious meat, and one “fish” can last a long time.
Origin of the species and description
Catfish are ray-finned fish – the first representatives of this class appeared in the Devonian period, about 390 million years BC. Gradually, they settled over ever larger territories, more and more new detachments and families were formed. The order of catfish is quite ancient – this is confirmed by many features of its representatives. So, among them there are species with spikes on their heads and fins, or with skin teeth similar to those that sharks have.
Another important feature indicating the antiquity of catfish is the presence in the skull of some of them a pineal opening, the same as in the lobe-finned or extinct looped fish Osteolepis – it is intended for a light-sensitive organ and is not characteristic of other fish. Catfish are related to characins, cyprinids and hymnots – they all descended from the same original genus, the division occurred back in the Cretaceous, after which this genus died out, and they continued to develop. Catfish have more archaic features.
The order includes the catfish family, which includes about a hundred species. The most characteristic of them is considered to be an ordinary catfish – it will be considered further. It was described by Cal Linnaeus in 1758, the scientific name is Silurus glanis.
Interesting fact: Legends of cannibal catfish are associated with finds in the stomachs of giant individuals of human bones, as well as rings and pieces of clothing. Most likely, catfish simply ate already dead bodies that ended up in the river – there are no reliably recorded cases of killing people by them.
Appearance and features
Previously, giant catfish were caught in European rivers – their body length was up to 5 meters, and their weight was up to 400 kilograms. These data inspire confidence, since the largest of the individuals designed according to all the rules is only slightly inferior – its weight turned out to be 306 kg. However, catfish grow all their lives, which means that they reach such sizes very rarely: over the past decades, individuals heavier than 160 kg have not been caught – and even such a weight is already huge for catfish. An adult is considered a fish weighing from 12-15 kg, and individuals heavier than 30 kg are very rare – this is a great success for the angler.
The head of the catfish is large relative to the body and looks as if flattened. The jaws are massive, but the teeth are very small – but there are a lot of them, and they are sharp. The eyes are small compared to the size of the head. A characteristic sign of a catfish is a mustache, two long and four more short. The color of a catfish can vary greatly, depending on where it lives and what time of year it is. Most often, its body is dark gray on top, and the belly is lighter. The fish may be light brown, greenish, sandy yellow or very dark. Often there are spots on the body.
The fins are usually darker than the rest of the body, they can be either very dark, close to black, or dark blue or dark green. Often, catfish combine several shades at once, smoothly turning into each other – in young individuals, these transitions are sharper, their colors are generally brighter than in adults, and even more so in older catfish.
The body of the catfish has a rounded shape in front, but the farther to the tail, the more compressed. The tail is very strong and long – about half the entire length of the fish, the fins are generally quite powerful, but due to their size in speed and maneuverability, catfish are inferior to most other fish. There are no scales, instead their skin is protected by a large amount of mucus – the sebaceous glands that produce it are actively working. Thanks to the mucus, the delicate skin of the catfish remains intact, and its body slides more easily in the water.
Where does the catfish live?
Found in most of Europe, including all of European Russia.
There are catfish in the basins of such rivers as:
That is, the common catfish is distributed almost throughout Europe, with the exception of the lands adjacent to the Mediterranean Sea, namely : most of the Iberian and Apennine peninsulas, Croatia, Greece, almost all of Scandinavia.
Previously, it was not found at all in the Pyrenees and in the Apennines, but it was introduced back in the 19th century into the Ebro and Po river basins, where it successfully multiplied. The same practice was used in many other cases, for example, catfish were not previously found in the rivers of France, the Netherlands and Belgium, Denmark – but after the introduction they took root.
Outside of Europe, they are found in the northern part of Malaya Asia and Iran, as well as in Central Asia – the Amu Darya and Syr Darya basins. In Soviet times, catfish were released into Lake Balkhash, and now they feel great both in the lake itself and in the rivers of its basin.
Catfish are very fond of large, full-flowing rivers and reach especially large sizes in them. Many large catfish are caught in the Volga and the Ebro. They prefer warm waters, therefore they are not found in the rivers of the Northern Ocean basin east of the Urals. Although they usually live in fresh water, they are able to live in salt water – for example, in the Black Sea off the coast of Turkey, in the Baltic and Caspian Seas.
All this applies to ordinary catfish, other representatives of this genus are also common in Asia to the east – for example, Amur catfish lives in the rivers of China, Korea and Japan, and loves Amur most of all, other species are found in South America, India, on the islands of Indonesia, and Africa.
Ordinary catfish live at the very bottom of the reservoir, usually they find a quiet place – a hole between snags, and settle there. Far from the chosen pit they do not sail even during the hunt, but spend a significant part of the time right there. They rarely change their habitat, they can even spend their whole lives in one place.
A change can be prompted by a lack of food – then the catfish swims to where there will be more prey, or cloudy water – they are very picky about its purity. Therefore, if the water becomes cloudy during the floods, the catfish can go in search of a new place to live.
Now you know where the catfish lives. Let's see what big fish eat.
What do catfish eat?
The diet of a catfish is very diverse, it includes:
They often eat carrion, which is why there is a common misconception that they are limited to it – it is due to the fact that this big fish looks slow and clumsy. But she is more dexterous than it might seem, and although carrion really makes up a significant part of the menu, she is not averse to eating living creatures of catfish.
So, they hunt a variety of fish – they can swim right into schools of small fish and, opening their mouths wide, eat them in dozens at once, or hunt large ones, like bream or pike perch. They can also dine on large amphibians like frogs, newts or waterfowl – although they are rarely caught.
They can catch and eat pets caught in the water – cats or small dogs. There are even cases of attacks on calves caught in the water and, moreover, on people. It is difficult to say whether the catfish is really dangerous for a person, it is reliably known only about the people bitten by them, who accidentally stepped on their nest.
Young catfish feed mainly on fry of other fish, aquatic insects, small crustaceans and larvae. In adulthood, they can also eat all of the above, but do not hunt for them on purpose – they simply open their mouths and suck all these small living creatures into it.
They hunt mainly at night, while they can both look for prey at the very bottom , and rise to the surface, where you can find small fish. They remember where the old net was left, and constantly check it to see if the fish got tangled there.
For the most part, they feed on fish, and during the hunt they can hide – usually the color of their skin merges with the river bottom, so that the victim may not notice the hunter for a long time until he is almost in his very mouth. If she still managed to escape, the catfish does not pursue her for a long time.
They are distinguished by voracity: even considering their size, they eat a lot, especially in spring, after nature comes to life and there is more prey – during the winter they get pretty hungry. Here everything is eaten, up to aquatic vegetation, although usually catfish prefer animal food.
An interesting fact: Whiskers are very important for catfish, they are used to search for prey – even in complete darkness, with their help, catfish feel its approach. In addition, they can act as bait – hiding, he exposes them and lures small fish, mistaking them for prey.
Catfish are homebodies and loners – they live for a long time in a quiet hole that they like and do not want to let anyone in to it. But this applies to adults – just as the fry keep in flocks, so the already slightly grown catfish remain in them for the first years of their life. If there is a lot of food, then they can stay together until the age of 3-4 years, then they have to blur because each fish needs a lot to feed, and therefore each adult catfish must occupy its own territory, from which it can feed freely.
The catfish is active at night or at dawn – the latter refers primarily to young individuals who prefer to feed in shallow water near the coast. During the day, catfish prefer to rest in their lair. If the weather is very warm, they can get out of the holes during the day and swim slowly, enjoying the sun.
They love warm and clean water. When it rains heavily and the water becomes cloudy, they get out of the lair and stay near the surface, where it is cleaner. Catfish swim up even before a thunderstorm – they leave behind even traces that differ from those that mark the movement of smaller fish, experienced fishermen also know splashing during their movement and are able to distinguish it from that emitted by other fish. Fishermen often use a good sense of smell of catfish – throwing food waste into the water and adding something freshly fried on a fire. A strong smell attracts catfish, and they rise from their depths to see what emits it.
In winter, their activity subsides: they gather in flocks of 5-10 individuals and lie down in wintering pits. They eat very rarely at this time, most of the time they spend motionless, falling into a semblance of hibernation. By spring, they lose most of the fat accumulated during the warm season, but it barely warms up, as they begin to actively eat again.
Catfish live for quite a long time – 30-60 years, and the oldest and largest specimens caught were 70-80 years old. With age, the catfish becomes slower, while it needs more and more food, instead of active hunting, it begins to simply swim with its mouth open, trying to suck living creatures into itself – it spends more and more time on food and it becomes more difficult for it to feed itself.
Social Structure and Reproduction
Catfish spawning starts when the water warms up enough – they need a temperature of 16-18 ° C. Depending on the habitat, this can occur from early May to early July. Before spawning, the male builds a nest – he finds a convenient place in shallow water, digs a hole in the sand, and then the female spawns there.
On average, per kilogram of mass, she throws 30,000 eggs – that is, if she weighs 25 kg, then there will be 750,000 eggs! Of course, only a small part of them will become fry, and even fewer will live to adulthood – but catfish breed quite efficiently. This is shown by the practice of launching them into rivers where they were not previously found: if the habitat suits them, then the initially small population of catfish after only a few decades grows strongly, and after 50-70 years there is no longer any difference with those rivers where they are historically, there are just as many of them in the new ones.
After spawning, the female swims away – she is no longer interested in the fate of the offspring, and all worries remain with the male. He is almost inseparably at the nest and is engaged in the protection of eggs, and also constantly brings fresh water saturated with oxygen to the nest – this is necessary for the best development of offspring. After 10 days, fry appear – they are about 6-8 millimeters long and look like tadpoles. After hatching, they attach to the walls of the nest and remain in this position for about a week and a half, feeding from the yolk sac.
Only then they begin to swim and look for food – but at first they do not move away from the nest. All this time, the fry are completely defenseless, because the male stays with them and protects them from predators. After four weeks, they blur – young catfish are divided into several groups and stay together for another year or two, and sometimes longer.
Natural enemies of catfish
The only enemy of adult catfish is man. Not a single river fish is able to compare with them in size, and even more so does not attack them, so that they live quite freely in the expanses of water and suffer only from human activity. At the same time, adult catfish peck less willingly, but fishing is still the main cause of their mortality.
Underwater hunting for catfish is much less common, in which hunters go down with scuba gear – this way you can catch even the largest of them. But many adult catfish still manage to successfully live to old age. It is more difficult for young people to do this, mainly because they peck much more willingly and are caught more often.
But even young catfish are not threatened by anyone except humans. Other predatory fish can only be a threat to them while they are still very young, and it also often devours eggs or fry. It can be pike, burbot, asp, and almost any other river fish. But juvenile catfish are usually protected by an adult male.
Interesting fact: Electric catfish is one of the most interesting catfish. He lives in Africa and is able to generate a strong electric current – up to 350 volts, thanks to the organs located under the skin that cover most of his body. With the help of electricity, this catfish stuns its victims and defends itself from enemies.
Population and species status
Nothing threatens the species, and its population in European rivers is very large. This is a fish that is actively hunted, since its meat has high palatability, it is tender and fatty. Due to too intensive fishing during the 20th century, a decrease in the number of catfish was noted in the rivers of Russia, but so far it is not critical.
Although in some river basins it has become really rare – for example, in Karelia. Catfish catches in the country as a whole have fallen significantly. But, as European practice shows, if you stop catching this fish too actively, it will quickly multiply. So, a few decades ago, catfish were practically not found in the Rhine and to the west of it, however, now there are a lot of them in this river, as well as in the Ebro. Catfish in these rivers are also growing in size every year – for example, fish weighing 60-70 kg have already ceased to be a curiosity.
Their population in any river basin is also growing rapidly, if the locals do not too actively catching them. That is why the balance is shifting more and more to the west – there are a lot of catfish in the rivers of Western and Central Europe, and less – to the east, in their traditional habitats, because they are too much loved to eat.
The largest predator of European rivers is catfish, the desired prey of any fisherman. They are fried, they make delicious fish soup, pies, meatballs, baked with vegetables, stewed – in a word, they have come up with many ways to use their tender meat. Catfish are so loved that their numbers in Russian rivers have declined – but in no case should one lose such a valuable fish.