Som is a major accesata fish that live in fresh water. Belongs to the family of catfish. This species is widely distributed in Europe. The habitat covers the majority of European countries except Spain, the UK, Italy, Norway. In the North the fish can be found in the southern water area in Sweden and Finland. In the South area of distribution reaches the coastal waters of the Black and Aegean seas. In Russia fish is spread up to the Urals. It is also found in Asia. The Aral sea basin. Members of the species and swim in the salty waters of the Black, Caspian and Baltic seas. The highest concentration observed at the mouths of large rivers and reservoirs. In the upper reaches of rivers is rare.
Body soma long. In front of it is rounded, and the rear part is compressed laterally. The head is broad and flat, eyes small and shifted to the frontal area. In the mouth has many small teeth. In the upper jaw are long whiskers one on each side. In the lower jaw there are 2 short whisker on each side. A long anal fin which reaches almost to the caudal fin. The dorsal fin is small, sharp and shifted towards the head. The pectoral fins are broad. Their fish creates a vortex in the water to disorient the victim. The skin is slippery and smooth. Scales out of it.
Body colour not monochrome. Back cantenna, almost black. The flanks are greenish-brown and diluted by lighter spots. The belly is light gray. It is more correct to call it off-white. In waters with flowing water the fish is lighter colored, and in stagnant waters it is much darker.
This fish has very large dimensions and weight. Length up to 4 meters and can weigh more than 180 kg. But these maximum figures are a rarity. The giants caught in the XIX century. They reached a length of 3 meters with a weight of 200-220 kg. still, there is talk that in 1856 in the river was caught a catfish with a length of over 5 feet and weighing about 400 kg.
In our day the regular size of a species reach 1.3-1.6 meters. Fish more than 2 meters in length and weighing 70 kg is considered the greatest rarity. Typically weighing 15-20 kg at a length of 1.5 meters. That the fish has reached a truly large size, need a very good habitat conditions. However, it can reach 2.5 meters in length and weigh 90 kg. Maximum recorded weight is 144 kg with a body length of 2,78 m.
Reproduction and lifespan
Reproductive age of this fish comes with a body length of 50-60 cm and weight of 2-3 kg. the Spawning takes place in spring or summer months depending on the region. The water temperature is 17-20 degrees Celsius. In favorable conditions, females can produce up to 2 servings of caviar. Eggs usually up to 30 roubles per 1 kilogram of body weight. That is, the heavier the female, the more eggs. The size of a ROE range from 1.7 to 3 mm.
The female before spawning is building a nest on river or lake bottom. Fossa is a flat round shape, covered with vegetation. She is always in shallow water, where the water surface is not more than 50-70 cm Caviar has a sticky structure, so is glued to the bottom and the walls of the slot. All the time while the eggs are developing, they are protected by the male. The development period typically takes from 3 to 10 days. It all depends on the water temperature. Initially formed larvae, after yolk SAC is resorbed, the larvae hatch length 15 mm They leave the nest and begin to lead an independent life.
Growing fish quickly. This is especially true of the southern rivers. For the first year of the life of catfish can reach a length of 30-40 cm with a body weight of 300-500 grams. To 10 years the fish grows up to 1.25 meters and weight gains of 15-20 kg, In the Northern rivers for 10 years members of the species grow only up to 1 meter. The lifespan of this fish is 30-35 years. Among young individuals, the mortality rate is very high. To year live only 5% of young catfish.
Behavior and nutrition
Migration is limited, so nursery areas and spawning are close by. Lifestyle single. In winter, the fish congregate in large flocks and waiting out the cold in deep holes. However, they stop feeding until spring. This species is a large underwater predators. The way of life he bottom. Choose a quiet underwater areas that abound with driftwood and caves.
Hunting is ambush. Fish makes the shot and grabs sailing close to the victim. Sometimes soma is combined in a large flock in shallow water, where there is a move of small fish. They turn around against the current, open mouth and swallow at once the whole bevy of young. Hunting is carried out mainly at dusk. The potential victim help you to find the whiskers on the face and sensitive skin. The diet consists of demersal fish species. This carp, perch, goby, various species of sturgeon and herring. The predator also eats crayfish, frogs, rodents, birds and insects. Sometimes also on carrion.
Humans consume only young members of the species. Their weight does not exceed 15 kg. heavier and larger catfish are very fatty, so is not recommended. The ROE of this fish are poisonous and not suitable for consumption.