Catfish Fish, Description
This thermophilic fish reaches its greatest abundance in the basins of the Caspian, Aral, Azov and Black Seas, mainly in the estuarine spaces and deltas of the Volga and Don rivers. In the Arctic Ocean basin, this fish is not.
Som is the largest predator of our reservoirs. He has an elongated body, covered with small tight-fitting scales, a huge head. the mouth is equipped with brushes of small but sharp teeth, a pair of long whiskers on the upper jaw and four shorter ones on the lower jaw. Som is able to swallow prey, sometimes slightly inferior to it in volume and weight (however, this is extremely rare for it, most often small bottom fish, mollusks and crayfish serve as food).
At the end of the 30s, fishing cooperatives caught catfish weighing over 300 kilograms and a length of more than 5 meters. Now such instances are not found. Under favorable conditions and the availability of food supply, the weight of a catfish at the age of 4 years is approximately 5 kilograms, at 8 years old – 16, at 15 years old it ranges from 30 to 40, in 20 – from 60 to 120 kilograms. The maximum age of the catfish is 25-35 years.
Despite the fact that in recent years poaching has been actively flourishing and the whiskered giant is finding it increasingly difficult to live to an advanced age, almost every year amateurs manage to catch giants at 100 kilograms. In central Russia, even in large rivers, catfish are distinguished by their stature, here its weight rarely reaches 15-20 kilograms. In lakes and reservoirs, it can be even less: 5-7 kilograms, despite the seemingly good forage base.
In most cases, catfish stay in deep holes located near the channel (Fig. 1). Catfish pits are often littered with fallen trees, topljak and felling. All this serves as a shelter for him from a strong current and at the same time as an ambush. Som does not like fast flow and goes to the mainstream only during the hunt. The pit where the catfish lives usually has one exit to the main channel, the other always goes aground or a long ridge of rifts. Having fallen in love with a particular section of the river, catfish leave their possessions, as a rule, only during periods of spawning and autumn rolling to wintering places.
If in large rivers the length of the paths of seasonal migration of catfish can be tens or even hundreds of kilometers, then in small rivers (with an abundance of feed) the movement of catfish can be limited to 10-20 meters. Having fallen in love with the bend of the channel of a small river or an ordinary ditch adjacent to it, the catfish stays in it for almost the entire season and leaves it for a short time, only to get food.
The vital activity of the catfish is often limited to the space of one reach. In the shallow rivers of the Moscow Region, he simply has nowhere to go, since he cannot settle all over the river due to unfavorable conditions: shallow water, a silty friable bottom, densely of food, competition from other predatory fish. Under such conditions, the weight of the predator does not exceed 1.5-5.0 kilograms.
With an abundance of feed in the pit, they can live from one or two catfish (in the rivers of central Russia: the Moscow River, Oka, Klyazma) to 100-300 individuals of the same age and weight (in the deltas of the Volga, Akhtuba, slightly less in the Don and Kuban) .
Som and burbot are not related, and yet these fish have a number of common qualities and functional features. Som and burbot – orderlies of the underwater world. Despite significant differences, they have a certain external similarity and are clearly tailored to the same type. Nozzles such as a frog, bait fish, rotten meat, a bunch of crawls are a treat for both.
Catfish and burbot are bottom fish, the trails of which pass in the immediate vicinity of the bottom, so they avoid the muddy and viscous bottom, preferring to stay in clean running water.
Catfish and burbot – fish are not schooling, but under favorable conditions and a sufficient food supply in small areas of the water body, an accumulation of individuals of the same age and weight is observed, where they are quite tolerant of each other. Both of these fish are a kind of homebody, adherents of once and for all selected places.
Perhaps the similarity ends here, the differences begin. Catfish and burbot cannot get along with each other on the same territory: the catfish easily deals with smaller burbot. If burbot produces food only from the bottom or in the immediate vicinity of it, then catfish hunts for prey both in the water column and near the surface.
40 percent of the catfish feed base is made up of juvenile fish and small fish that do not have sufficient nimbleness (gudgeon, ruff, loach, minnow, perch, sculpin, flock of yearlings of white fish). Catfish weighing up to 10 kilograms actively pursues and attacks even schools of roach, scavenger and other white fish. Having achieved more weight, due to his slowness, he practically ceases to chase a fast fish, attacking a victim only from shelter.