Sterlet is considered one of the oldest underwater creatures on the planet. Fish is very valuable and is protected in all countries due to the small population. The attitude to the sturgeon class and the outward resemblance to stellate sturgeon, sterlet and other representatives often mislead inexperienced fishermen who cannot determine exactly what kind of fish they got into the net. Sterlet has a lot of features by which a knowledgeable person can easily distinguish it from other marine inhabitants.

Origin of view and description

When the Silurian period was going on Earth (from 440 to 420 million years ago), many underwater creatures evolved greatly. Their gills have changed significantly: from ordinary rings, they turned into two arcs, fastened by the articular part. This slightly changed the process of producing oxygen. Then the oral cavity began to transform. The upper arch fused with the skull, and the lower remained mobile and turned into the lower jaw. So the creatures got a full mouth. Such a transformation has undergone many ancient fish, including the distant ancestors of the sterlet.

This turned evolved species into predatory animals. If earlier underwater creatures were forced to feed on plankton and small algae, because they couldn’t chew larger food, with well-formed jaws they were able to tear and grind large pieces. Due to this, the diet of such creatures has expanded significantly and replenished with small fish.

It must be understood that the ancestors of the sterlet, who lived 400 million years ago, externally differed from modern ones. Unfortunately, scientists cannot determine exactly what they looked like. Most likely, the fish of that time were larger and could differ in body structure and color. The first individuals, outwardly similar to the modern sterlet, began to appear about 120 million years ago.

Interesting fact: Given that over the past 100 million years, the sterlet has not practically changed externally, it can be considered a real underwater dinosaur.

Over time, this species has proven to be one of the most enduring shellfish. He confidently survived any global catastrophes, managed to adapt to changing weather conditions, and also always gets along with other life forms.

Appearance and features

Sterlet belongs to cartilaginous fish. She does not have vertebrae in her body, and their functions are replaced by durable plates located on the sides. The base of the skeleton is a chord, which is visible to the naked eye thanks to the spikes evenly distributed along the back. The skull and skeleton of even adults consists of cartilage.

The mouth is pushed forward and resembles a duck beak. There are no teeth on the jaws, but thanks to the hard larynx and large oral cavity, even large pieces are well grinded. In the lower part of the body is a swimming bladder that has connections with the digestive system. At the base of the head, under special covers, there are gills. They contain small openings that allow air to pass through.

The sterlet boasts a long, flattened body on the sides. The head is stretched forward and has a forked lower lip. Also at the bottom of the head are small antennae, which are characteristic of other species of sturgeons.

The fish is divided into two subspecies according to the shape of the head: with a sharp muzzle and with a flat snout. The first are born in natural conditions. Individuals with a flat snout can also appear in water bodies, but they are not able to produce offspring. Interestingly, most individuals that appear during artificial breeding also have a flat snout.

The body of the fish is gray in color and has a light belly, the body is covered with scales similar in composition to tooth enamel. On the head are bone plates that serve as protection.The dorsal fin is not located in the center of the back, but is shifted towards the tail. The latter has an elongated upper part and a short lower.

The average size of the sterlet ranges from 0.5 meters, but especially large individuals can grow up to 1.4 meters. Males and females of the same color, size, and outwardly do not differ from each other.

Habitat - where is the sterlet found?

Sterlet lives in rivers with access to the sea or lakes. They are most common in the Yenisei, the Northern Dvina and the Ob. They are also found in many rivers flowing into the Black, Azov and Caspian Seas. Moreover, the sterlet got into some water bodies thanks to the person who launched them in order to increase the number. Currently, the largest populations live in the following places:

• a large school of fish lives in the middle reaches of the Irtysh;
• The Kuban is considered the southernmost habitat of the sterlet; a small population of this species lives there, but its number is gradually increasing;
• In recent years, the Kama River has been greatly purified from water due to the cessation of deforestation, which is why the local fish began to breed zealously
• things are not going well on the sterlet in the Sura: because of not very favorable conditions, their numbers are gradually decreasing;
• in the Don and Urals this species of fish is a rare sight; most likely, some individuals swim here, but do not live on a permanent basis;
• to increase the population, people artificially introduced sterlet to Amur, Oka, Neman and Pechora;
• fish are quite common in the Yenisei; several large schools live there;
• Ob this species is just beginning to develop, periodically catching the eye of a person;
• The sterlet was specially delivered to Dvina, but for a long time it could not take root due to cold weather conditions.

Fish prefers to settle in reservoirs with a ground or sandy bottom, and it also needs very clean water. Males spend most of their time at medium depths. Females prefer to sink to the bottom.

What does sterlet eat?

Young individuals eat plankton and small aquatic organisms. They move along the bottom and collect with their mouth everything that they can eat. The antennae located on the upper jaw and serving as sensors for detecting edible help them in this.

As you grow older, the diet of the fish changes slightly and depends on gender. Since males swim at medium depths, they prey on small fish. Females, spending most of their time at the bottom, eat marine insects, worms, small crustaceans, and eggs of other fish.

Despite the fact that the sterlet is considered a predator, it prefers to choose smaller prey. She goes hunting at night or in the dark.

Interesting fact: unlike many fish, sterlet does not have cannibalism. Adults do not attack young animals and do not eat their own eggs.

How long does a sterlet live?

The life expectancy of sterlet is very long compared to other marine inhabitants. On average, under favorable conditions, fish can survive up to 30 years. Scientists also believe that some individuals are able to reach 80 years. Sterlet grows and develops for a long time. Her body is finally formed by 5-7 years.

Features of character and lifestyle

Sterlet is a predator that settles in reservoirs with clean water. Sometimes individuals can go to sea, but always quickly return. In the warm season, the fish swims in shallow water, but with the onset of cold weather it goes to the side from the coast to a greater depth and looks for pits and ravines for wintering. Uninvited guests will not find her there, and the fish will be safe.

In winter, the sterlet becomes inactive. She spends all the time in the recess she found, she does not go hunting. Her body falls into a state of suspended animation, because of which he does not need to regularly receive food. With the onset of spring, when the ice on the surface of the river melts, individuals begin to move a lot and go upstream to spawn.

Social structure

Sterlet lives in large flocks, and the number of individuals can be several hundred. The fish collect food together and try to take care of the young. Perhaps it is due to the developed social structure that this species has not only not disappeared from the face of the Earth, but also increases the population.

Interesting fact: Sterlet is the only representative of sturgeon that live in large groups, and not individually.

When the wintering season comes, the fish together look for a place where you can wait out the cold. Having found a suitable crevice or large recess, the sterlet sinks to the very bottom. Sometimes so many individuals can gather in a ravine at the same time that they cannot even move their fins freely. Then the fish are tightly pressed against each other, fall into suspended animation and become motionless.

Breeding - spawning

Males are capable of producing offspring as early as 5 years old, and females finally mature by 8 years old. Spawning begins after winter, the fish is able to spawn once every two years. After this process, the female is greatly depleted, and she needs time to recover. The most favorable period for spawning sterlet is the period when the water temperature ranges from 10 to 15 degrees.

For throwing caviar, the fish chooses places with an intense current and a pebble bottom. At one time, the female can lay from 15 to 60 thousand eggs. The latter have an oblong shape and a black and golden hue.

Interesting fact: albino sterlet forms yellow caviar; it is considered a particularly valuable delicacy.

The laid-off caviar is covered with a special sticky substance that allows it to stick to stones even with a strong current. To form under the shell and hatch, the fry need several days. Having been born, within 10 days they adapt, learn to navigate in space, their yolk sac disappears. At this point, their length is about one and a half centimeters.

The fry are darker in color than adults. For several months, they swim and develop in those areas where they were born. When their size becomes 15-20 cm, they swim at the mouth of the river and join the local flock.

Natural enemies of sterlet

Since the fish lives mainly on the river bottom, it remains invisible to most predators who prefer to stay at medium depth. Sterlet has practically no one to fear, and in the event of an attack, its bone plates located throughout the body will be able to protect it from bites.

And if nothing threatens adults, then fry and eggs cannot feel safe. They often become food for sturgeon, pike, burbot, pikeperch and catfish.

Also, this species is susceptible to various diseases, which is why it prefers clean water, where there is a minimal chance of getting an infection. Sterlet often encounters the following diseases:

• saprolegniosis;
• gill necrosis;
• gas bubble disease;
• myopathy

Therefore, with artificial breeding, a person carefully monitors the created conditions.

Sterlet fishing

The sterlet is listed in the Red Book, therefore, in most regions its fishing is prohibited. In those rivers where trapping of this species is permitted, a license is required, which the local guard must necessarily present. Violation of the law may result in a fine or institution of a criminal case.

Interesting fact: even if you have a license, you can’t catch more than ten fish at a time, and prey must be released. It is forbidden to use nets for capture.

Since sterlet caviar is of great value, some poachers try to get it by any means, despite the current laws. They catch individuals during the spawning period, gutting and selling goods in clandestine ways.

In Russia, sterlet is allowed to be hatched under artificial conditions, and it is precisely such fish and caviar that can be purchased in shops and restaurants.

Population and species status

In the second half of the 20th century, the sterlet had no problems with the abundance of the species. However, heavy river pollution and illegal hunting greatly reduced the population. At the moment, the sterlet in the international classification has the status of “vulnerable species”. In the Red Book, it is marked as “disappearing”.

To increase the number at the beginning of the 19th century, people began to breed sterlet under artificial conditions, and with a plentiful increase in the population, they quickly began to use it for commercial purposes.

Now there are a large number of fish farms where this species is grown. Its individuals serve as donors to replenish the number of schools in certain rivers and for the manufacture of food products.

Special attention is paid to the breeding of sturgeon hybrids. Bester obtained during the merger of beluga and sterlet is very popular.

Sterlet guard

Sterlet plays an important role in the ecological system of rivers. By constantly eating small insects, crustaceans and plankton, it prevents their abundant distribution. Man makes every effort to save this species from extinction. For this, special programs are being developed to create favorable conditions in the rivers, and individuals are being acclimatized.

There are also laws restricting the activities of fishermen. To capture fish, a license is required, according to which a person can catch no more than 100 pieces. sterlet per month. And to build up the population, artificial reservoirs are created.

It is worth noting that people's efforts are rewarded with a positive result. In recent years, the total number of sterlet in the world is growing steadily.

Artificial breeding

Specially equipped pools are created for artificial sterlet breeding. They maintain the right temperature, special sensors help monitor the saturation of water with oxygen.

Interesting fact: sterlet requires saturation of water with oxygen not lower than 5 mg / l, otherwise it will begin to suffocate.

In artificial favorable conditions, individuals develop much faster. After 10 months, they can grow to large sizes and weigh around 500 grams. Other sturgeon species can also be hooked to fish in order to create more valuable hybrids. Fortunately, the sterlet gets along well with them.

Sterlet in heraldry

Sterlet is found in heraldry and serves as a symbol of many cities and regions. Among them:

• Saratov;
• Rybinsk;
• Belozersk;
• Yeisk;
• Tsaritsyna (coat of arms was used before the city was renamed Stalingrad).

In most cases, the fish is shown in gray or white. Tail and fins turn red. It was not by chance that the locals chose sterlet as a symbol, as it lives in large numbers in their reservoirs.