Sterv photo and description, characteristic and type of fish | Red Book

Quite often, representatives of the sturgeon family mean large fish, which can reach several meters in length and hundreds of kilograms in weight. Sterlet the smallest in its parameters among all members of the family. And it stands out by an unforgettable taste, due to which it is called “royal fish”.

Sterlad (lat. Acipenser Ruthenus linnaeus) is one of the fish brought in the Red Book of Eurasia, belongs to the sturgeon family and is considered the smallest in it.

Appearance and structure

The average length of the body of an adult of about 50-70 centimeters, but scientists recorded a few “giants”, the dimensions of which reached more than 120 centimeters. Weight varies from half a kilogram to two or three, the smallest of all registered fish was three hundred gram. In the old editions of the nineteenth and twentieth century, sterlet could reach twenty kilograms.

The body is oblong, this form contributes to better movement during strong currents. The jaw is lowered in the head, but at the end it rises slightly. Two varieties of sterlet are usually distinguished in the shape of a head: sharp and dumb. The pupils are large, in color it can be either yellow or brown. Sterlad is similar to a young shark in terms of its parameters-she has gill holes behind her eye sockets, spray. They help draw wildness, and then send them to the gills. Another similar feature can be called their skeleton: bone plates are located on the surface of most parts of the body that can withstand huge pressure.

Any representative of the sturgeon has a lot of bone shields, but it is sterlet that is most of them: about sixteen dorsal, as many abdominal and more than seventy lateral. They are located in several rows, the skin between the shields is covered with bone scales, the belly is protected by solid formations.

The mouth is small, located at the bottom of the jaw, for eating food is advanced. This fish has no teeth, although small fangs are present in fry, since their chewing muscles are not yet developed.

The fin on the back is strongly set back, so the fish has much more maneuverability. It has partial pointing and is composed of several dozen rays. The tail fin is located vertically, which even more shows the similarity between sharks and sterlet. Any of the fins has fat deposits near the base this is necessary to tightly fix radiation processes.

Habitat

Sterlad is found only in freshwater reservoirs, mainly the habitat are clean lakes and rivers, in which there are a lot of oxygen. This individual gives its preference to pebble and sandy soils.

Representatives of this species can be found in many rivers of Siberia, as well as most reservoirs that are somehow connected to the largest seas of Europe and Eurasia. For a larger population, Sterlad was artificially populated in Pechora, Amur, Western Dvina and Oku. Occasionally found in the area of ​​Pripyat.

If we take into account the territory of the CIS, then most of all this fish is found in the rivers of the Siberian and European part. Many areas are also concentrated in most Eurasia countries.

Food

Despite its modest size, sterlet is considered a predator who needs large doses of protein in the diet (about fifty percent of all nutrients). Food mainly consists of invertebrates living at the bottom, because hunting for them is not difficult. Worms, larvae, aquatic insects and small crustaceans can be considered a frequent dish. Midges, mosquitoes, moths, sideworms, curses scientists find all these small inhabitants of the underwater world in the stomach near Sterlet. In rare cases, when the size of the individual reaches its peak parameters, this fish begins to eat frogs, small fish and mollusks.

Bokoplava Food Sterlad

Another feature of these sturgeons can be called the difference in nutrition between male and female individuals. Due to the fact that the main habitat of females is the bottom, they eat worms and other small insects that are found in silt. Males prefer to hunt their prey and eat invertebrates living in layers of fast currents.

Although in the classification of sterlet is considered a predator, in essence it is a collector, who only sometimes, due to a lack of food, begins to hunt for fry of other species, for example, crucian carp, silver carp or ruffs. This fish can find its food under large stones, because the elongated snout allows even a heavy cobblestone to turn up without any problems.

Fry have small fangs for cutting the booty, but they feed on smaller and weak food, unable to give any rebuff: infusoria, plankton of various kinds, cyclops and other spineless. After the deprivation of the gall bladder, which usually occurs after two weeks after the birth, very young representatives of the species begin to look for food on their own.

The most active period of feeding is the dark time of the day. Special gluttony in sterlet appears before the arrival of the reproduction period and after laying off the caviar. At this moment, the main goal of the fish is not survival, but “eating” they literally stick into themselves all the food that will fall along the way. This period is the most favorite majority of fishermen, because they can catch the already fed and fatty fish. But in winter their food period ceases, because spineless and other organisms fall asleep at a temperature below 4 degrees.

In the artificial habitat in the diet, shrimp may be present.

Lifestyle

Sterv is a night traveler who goes hunting at night, and hides and hides from everyone in the afternoon, trying to behave imperceptibly and not to show off again.

Upon occurrence of darkness, predators slowly but surely swam aground, look for food among algae and stones, and then turn upside down thus, they try to catch the fallen insects. In rare cases, these individuals can even arrange legendary “candles”, jumping out of the water behind their victims.

Throughout the year, representatives of the species try not to be divided and to migrate flocks, because single fish cannot stand up for themselves against other, not even the largest predators. And even if they do not eat the sterlet itself, they will certainly deprive it of any possibilities to find food for themselves, thereby the sea with hunger fish of modest sizes. In winter, all the way remain in one place and guard their refuge with all their might, and in the spring, when the ice is about to melt, they begin to lead life by a nomadic way.

Когда температура в округе теплеет, у рыб начинается нерест, во время которого стая начинает плыть вверх по течению. After the mating season, fish arrange mass feeding, without which they may die. The beginning of summer is indicated by the departure of fish to the riverbed, although it occurs at a rather slow speed. In winter, the most difficult period in the life of sterlet begins starvation, which ends only after warming. In order not to die from a lack of food, throughout the winter, sterlet does not move from the place that it will not notice and hide from the gaze of others.

Spawning

The beginning of the reproduction period follows a couple of years after the end of puberty. Females reach their puberty in the interval between 5-8 years. Males are developing slightly more and by three years of their life are capable of mating. Fertilization and subsequent spawning occurs annually, due to which females manage to recover after such a painful and difficult process.

Spawning begins with an increase in temperature to ten degrees Celsius. This period falls on the beginning of April or midJuly. The duration of reproduction varies from one to two weeks.

The main place in which the caviar will subsequently fall is riddles in rocky soil, which are on a rather large depth. Larvae are attached to stones, which provides protection and the inability to die at least during a strong current. Sterlad swores its caviar with several approaches, in total it comes out from ten to hundreds of thousands of eggs, which the males then fertilize their milk. Since females are exhausted much faster than the opposite sex, males have the need to fertilize the caviar of several individuals, which is why they are considered polygamous.

The shape of the sterlet is oblong, it has the colors of dark shades and on average reaches about two millimeters in diameter. Judging by the observations of some scientists, the color of eggs directly depends on the color of the sterlet, but it is the caviar of dark individuals that develops more rapidly.

On average, fry is born a week after the fertilization of caviar, they look like adults, but have a fullfledged mouth with their teeth, unlike the elderly. At first, young animals are near its place of birth, because it has no opportunity to hide or protect yourself from potential danger.

Life expectancy

The natural habitat allows sterlet to live up to thirty years. This is facilitated by great maneuverability and the absence of such large predatory fish in freshwater rivers. The most maximum age for a representative of this kind was a copy of fortysix years.

Composition and properties of meat

A sterlet has long been considered delicious fish, dishes from which only a limited layer of society can afford. The sterlet meat has an excellent unforgettable taste, it contains many beneficial substances, rich in proteins and has in its composition unsaturated fatty acids, which can sometimes be even necessary for a person.

Due to taste and special value, sterlet was often attributed to red fish, although its meat does not have such a shade.

Not a single water resident can do without parasites, representatives of this species also have both external and internal pests. But they are not considered dangerous for human health, so refusing to use such elite meat would be unforgivable.

Conclusion

Unfortunately, at the moment, the sterlet population is massively reduced and even begins to die out, so it will be problematic to taste dishes from the meat of this fish.

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