Sturgeon have long been valued by people due to the extraordinary taste of the most delicate meat and the unique composition of caviar. This is confirmed by archaeological excavations. They indicate that back in the sixth century, belugas up to 6 meters long were hunted in the Moscow River. The habitat of sturgeon fish is considered to be North America and Eurasia. Over 170 million years, they have adapted to a temperate climate and can easily tolerate lower temperatures.
What kind of fish is this
Today many similar sturgeon fish are known. Sturgeon individuals have common characteristics and a number of differences.
Where does she live
Sturgeons include different species - anadromous, freshwater, semi-anadromous. Anadromous are individuals that live in seas and rivers. During reproduction, they migrate from the sea to the river. The opposite situation is also possible, but it is observed much less frequently. Semi-anadromous fish live in coastal marine areas. They can also be found in seas and lakes. At the same time, such individuals move to the lower reaches of rivers to spawn.
Under natural conditions, sturgeon fish live in the waters of the Northern temperate zone of Europe. In addition, they live in northern Asia and North America. Over many years of evolution, the sturgeon has perfectly adapted to life in a temperate climate. This fish can withstand lower water temperatures and can remain without food for a long time.
Sturgeon are bottom-dwelling species that live at depths of up to 100 meters. Anadromous species live off the coasts of seas and oceans, but during the breeding season they move to fresh rivers. When the fish enter there, they swim against the current. In this case, individuals cover considerable distances. After spawning is completed, the fish move in schools back to the sea.
Semi-anadromous varieties prefer salty coastal areas of seas and oceans. At the same time, they move to river mouths to spawn, but do not go upstream. Many freshwater sturgeon species do not make long migrations. They prefer a sedentary lifestyle and live in rivers and lakes. This is where the fish find food and reproduce.
Sturgeon fish live in areas where there are no other large predators. That's why they have almost no enemies in nature. The fish that come across the sturgeon's path are not able to gnaw their bone plates. That's why no one attacks them. Sturgeons only have to be wary of people. For several centuries, people have been actively hunting sturgeon to obtain healthy meat and valuable black caviar.
It is worth considering that sturgeon are considered to be very demanding of environmental conditions. If fish enter a dirty pond, they can contract a large number of infections. Therefore, breeding sturgeon in artificial conditions is considered a very expensive activity. It involves the installation of special equipment.
What does it eat?
The basis of the sturgeon diet is bottom organisms and fish. At the same time, the nutrition of such individuals is directly affected by their age and habitat:
- The fry eat zooplankton. Their diet includes bosminamia, cyclops, and daphnia. However, sometimes these individuals also consume small crustaceans and worms.
- Young fish eat insect larvae. They also eat snails, small shrimp and crustaceans. It is worth noting that inedible fragments can also be found in the stomachs of fry. Most likely, they suck them out from the muddy bottom.
- Adults primarily eat protein foods. They become as voracious as possible before spawning. During this period, sturgeon eat almost everything that they can find on the bottom, including various crustaceans and representatives of the order Cladocera.These individuals often eat mosquitoes, insect larvae, and worms. Their diet may also include mussels, shrimp and leeches. Often adult fish feed on shellfish and caddisflies.
If sturgeon do not get enough protein, they may ingest algae. As for the fish diet, it includes herring, sand lance, and gobies. Sturgeons also happily eat mullet, pike-perch, sprat and many types of small and medium-sized fish.
During spawning and after the end of reproduction, sturgeon stop feeding and begin to consume vegetation. It takes about a month for the individuals to recover. After which their appetite returns. Then the fish again begins to look for food that will help it survive.
How long does he live?
During puberty, sturgeon begin to spawn. In most cases, reproduction begins in the spring and ends in November. The peak of this period is considered to be mid-summer. For spawning, fish prefer rivers whose temperature parameters are +15-20 degrees. If the indicators are exceeded, the probability of egg death is high.
Females go to spawn at intervals of 3-5 years. This happens more often in males. After the completion of the breeding season, sturgeons do not die, as happens with many other fish.
Immediately after birth, sturgeons hide under stones. This is due to the fact that they are not very good swimmers and have poor eyesight. After 10-12 days, the fry reach 2 centimeters in length. They actively absorb food, swim well and resemble adults in appearance.
During the first year of life, young fish remain in fresh water. They can also live on the border with salty bodies of water. The fact is that sea water is considered deadly for such fish.
Sturgeons are characterized by rather slow development. Large varieties reach 28-35 centimeters by the age of 2, and approximately 70 by the age of 4. Only by the age of 12 do these fish reach medium size.
At the same time, the lifespan of sturgeon depends on their variety:
- Stellate sturgeon lives 30 years;
- sturgeon can live up to 50 years;
- Beluga lives to be 100 years old.
It is worth considering that the lifespan of sturgeon depends on a number of factors. First of all, this parameter is affected by the seasonal water temperature. Water pollution is also of great importance.
What does sturgeon look like?
The sturgeon is characterized by an elongated, spindle-shaped body, which is covered with a number of bony spines. It is noteworthy that representatives of this family do not have vertebrae. The structure of the skeleton includes only cartilage tissue. In this case, the notochord is retained in fish for life.
At the bottom of the spine is a large swim bladder. It is attached to the dorsal part of the esophagus and makes it possible to descend to a depth of up to 100 meters. Sturgeons have 4 main gill openings, which are transformed into squirters. Inside these elements there are up to 45 gill rakers. As water is drawn into the gills through the squirter, sturgeons absorb the oxygen contained in it.
These individuals are characterized by a small, elongated head. It may have a sharp or slightly blunted snout of a spatulate or cone shape. At the end of the head there are two pairs of smooth whiskers, which represent an organ of touch. Fish use them to navigate in space and search for food by feeling the bottom of the reservoir. The mouth is located at the bottom of the head. When absorbing food, the fish extends its lips, which allows it to grab bottom organisms. The fry have underdeveloped teeth. As they grow, they disappear.
The color of a fish is largely influenced by its habitat. Experts are able to determine the river from which the sturgeon was caught by eye. Sturgeons are characterized by a light belly. It may be white or yellowish. The lower fin has the same color. The back and sides of the sturgeon are distinguished by a dark shade. It may be blue or greenish.
Body structure
Sturgeons are characterized by a rather interesting body structure, which allows them to be distinguished from other fish.
Scales
The body of representatives of the Sturgeon family is covered not with scales, but with skin. There are 5 rows of shields on it, which are arranged longitudinally. The line that runs along the back forms a sharp keel. Its structure includes 10-18 bugs. There are 25-26 scutes in the lateral rows, and 7-15 on the belly. The specific number of bugs is determined by the species. Bone plates with sharp spines resemble a shell. It provides sturgeon with reliable protection from large predators.
Liver
The liver of all varieties of sturgeon accumulates microelements. Therefore, it is important to consider what body of water they are found in. In unfavorable conditions, valuable fish accumulate harmful substances. Despite this, sturgeon liver contains many important elements. These include vitamins B, D, C, A. The product is also rich in phosphorus and potassium. Therefore, sturgeon liver should be consumed by people who adhere to a dietary diet.
Fins
The appearance of the fins depends on their varieties. The tail element promotes forward motion. It has a long top and an asymmetrical structure where the end of the spine extends into.
The dorsal and anal fins are used as a keel. With their help, the fish holds its body vertically. The dorsal fin is characterized by 25-50 soft rays that move towards the tail.The anal fin includes 17-32 rays. It begins at the end of the dorsal.
With the help of pectoral and ventral fins, the fish can turn, rise, and fall. It is worth noting that the chest elements seem stiffer. In this case, the front ray resembles a spike. From its cut, experienced fishermen are able to determine the age of the fish.
About sturgeon meat
In Rus', representatives of the sturgeon family were classified as red fish. In fact, their meat is white, pinkish-yellow or light pink in color. In any case, it is very beneficial for health.
Sturgeon contains a large amount of proteins that are easily digestible. Thanks to this, the product is quickly digested. It is not surprising that nutritionists recommend using it. Sturgeon meat contains a large number of valuable acids, including glutamic acid. It also contains vitamins B, C, PP, A.
Sturgeon meat is considered a delicacy. It includes many valuable micro- and macroelements. Among them, it is worth highlighting calcium, iodine, and potassium. Sturgeon is also rich in chromium, sodium, and iron. 100 grams of sturgeon contains 160 kilocalories. The energy value of sturgeon caviar is 200 kilocalories. The product contains a lot of proteins and lipids. Caviar is useful for people who are weakened after serious illnesses or have undergone aggressive therapy.
Due to the high content of fatty acids, sturgeon meat helps strengthen the heart and blood vessels. It lowers blood cholesterol and minimizes the risk of myocardial infarction. Sturgeon caviar has a good effect on bone development and normalizes skin restoration.
With regular consumption of sturgeon meat and caviar, it is possible to improve a person’s health and well-being. Sturgeon fat normalizes the functioning of the brain.In addition, fish helps cope with stress and improves the prognosis in the treatment of depression.
The most valuable caviar is stellate sturgeon, Russian sturgeon and beluga. The product comes in different colors and sizes. It is important to take into account that caviar and sturgeon itself can be infected with botulism pathogens. Therefore, fish can only be purchased from reliable suppliers. In addition, the product must be carefully inspected before purchase.
People who suffer from obesity and diabetes should consume this fish with caution. It is advisable to first consult your doctor.
Popular types
Today, many species of sturgeon are known, each of which is characterized by certain characteristics. Below is a list of the most popular varieties.
Russian sturgeon
This fish is found in the basins of different seas - the Azov, Black and Caspian. Russian sturgeon is predominantly an anadromous species. Freshwater individuals live in artificially stocked reservoirs. There is also a Russian sturgeon of a residential form that inhabits the lower reaches of the Volga. However, today it is on the verge of extinction.
Russian sturgeon lives up to 46 years. The average weight of the fish is no more than 25 kilograms. In favorable conditions, individuals can reach a length of 2.3 meters. Moreover, their weight is up to 115 kilograms. However, such individuals are extremely rare.
This species of sturgeon is characterized by constant spawning and feeding movements. Sexual maturity of the Russian sturgeon occurs at 8-13 years. Females are ready to breed at 8-20 years of age. To lay eggs, individuals need to enter rivers.
If the fish begins migration in the spring or in the first half of summer, it lays eggs in the same year. When entering rivers in autumn, reproduction begins only in the spring of next year. In this case, the water temperature should be +9-15 degrees. After spawning, the fish swims back to the sea. After switching to a mixed diet, young individuals begin to move en masse to the sea.
Depending on the habitat, the diet of this fish may be based on amphipods, mysids and worms. The Russian sturgeon also actively consumes fish. It feeds on herring, sprat, shemaya and mullet. In nature, these individuals can produce hybrid offspring with other members of the family. These include beluga, sterlet, and stellate sturgeon.
Sterlet
The natural habitat of this species of sturgeon is considered to be the rivers of the basin of some seas - the Azov, Black, Baltic. Sterlet can be found in the Dnieper, the Urals, and the Yenisei. It is also found in the Volga, Don, and Irtysh. Previously, these individuals could be caught in Lakes Ladoga and Onega. The fish is now classified as a vulnerable species.
Sterlet is medium in size. She begins puberty quite early. Males are ready to breed at 4-5 years of age. In females, this period begins at 7-8 years. The key difference between sterlet and other sturgeon species is the presence of fringed whiskers. They also have a lot of side bugs. Their number exceeds 50.
This fish is a freshwater fish. However, there are also a number of semi-anadromous varieties. The maximum length of a sterlet is 1.25 meters. Moreover, its weight reaches 16 kilograms. On average, the fish does not exceed 40-60 centimeters. It is characterized by a sharp or blunt snout.As for color, it can be brown or brown-gray. The fish has a white belly with a yellowish tint.
Sterlet feeds on insect larvae and leeches. It can also consume bottom organisms and some small fish. The hybrid of sterlet and beluga is of great value. It's called bester.
Shrenka (Amur sturgeon)
This fish lives in the Amur basin. At the same time, it moves to Nikolaevsk-on-Amur for spawning. Shrenka lives in fast moving water. In summer, it moves to floodplain lakes. In winter, the Amur sturgeon chooses deep places with rocky riverbeds.
The breeding period begins at 9-14 years. At this point, the length of the fish reaches 115 centimeters, and the weight is approximately 8 kilograms. Spawning begins at the end of May and continues until the end of June or mid-July. To breed, the shrenka chooses pebble shallows, descending to a depth of 2-3 meters. Amur sturgeon spawn at intervals of 4 years.
This fish is characterized by a spindle-shaped body, which is covered with small comb-like growths. Below the side bugs there are small plates that resemble stars. The snout is cone-shaped and pointed. It is complemented by 4 flattened mustaches, which are covered with almost imperceptible fringe. At the bottom of the head there is a small transverse mouth.
The body is yellow-gray or black in color. In this case, the abdomen and sides have a light shade. Shrenk's main diet consists of insect larvae, crustaceans, and mollusks. She also feeds on small fish.
Kaluga
This name is used to designate the largest representative of sturgeon. The fish can reach a length of 5.5 meters. Moreover, its weight is 1 ton. Kaluga lives up to 55 years.Its body is characterized by a heterogeneous gray-green color. The fish has a white belly. In this case, the back and sides have a darker shade.
Kaluga has a cone-shaped snout. It is pointed and shortened. The mouth resembles a large semicircle in appearance. The body is covered with bone plates. Kaluga is found in Arguni, Shilka, and Amur. It feeds on minnows, chum salmon and pink salmon.
Stellate sturgeon
This fish is considered a prominent representative of the sturgeon breed. It is characterized by an elongated snout of a flattened shape. The antennae are devoid of fringe, and the body is covered with bugs and star-shaped plates.
Stellate sturgeon is found in different seas - the Black, Azov, and Caspian. It is capable of descending to 100 meters in depth. The length of this individual reaches 2 meters. Moreover, her weight is 80 kilograms. The fish has a white belly. At the same time, the back and sides are distinguished by a blue-black color. The diet of stellate sturgeon is based on small fish - gobies and herring. It also feeds on worms, mollusks, and crabs.
Why did the population decline?
Back in the seventeenth and nineteenth centuries, up to 50 thousand tons of sturgeon were caught in the Caspian basin. At the turn of the nineteenth and twentieth centuries, production decreased to 29 thousand tons. In 2007, commercial fishing was completely banned in the Caspian Sea. This measure was associated with the need to preserve the population of valuable fish.
Ichthyologists identify 2 main reasons for the decrease in the number of sturgeons of different names:
- poaching - since the beginning of this century it has increased by a third;
- reduction of spawning areas is associated with the active development of the economy in river basins.
Sturgeon is a unique fish that is considered very popular. All representatives of this family have unusually valuable meat, and therefore are considered very popular.
