Sturgeon species can live in salt and sea water. Spawning occurs in freshwater rivers or other reservoirs. Fish of the sturgeon family relatively small sizes. Most often they reach body length in the range from 30 to 100 centimeters with a weight of 500 grams to 5 kilograms. However, there are also quite overall representatives. These are very valuable fish with a commercial value. Great demand has their meat and caviar, which have an excellent taste. Due to very mass fishing, which has reached extremely large volumes, the number of these fish began to seriously decrease. Another reason for the reduction of their number is predatory capture and strong pollution of reservoirs. Some representatives of the family are listed in the Red Book, and their catch is under a strict prohibition and control.
It is noteworthy that sturgeons have about 75 million years. They appeared even before bony waterfowl.
Types of fish of the sturgeon family
Kaluga is a rare fish of the sturgeon family, which is located in the International Red Book. It is a valuable fishing fish with a particularly revered caviar. Until some time, it was attributed to freshwater representatives, but it has recently been known that it also lives in the north of the Sea of Okhotsk.
Beluga is considered the largest freshwater fish that settled the reservoirs of Eurasia. It lives on the territory of the Black, Azov and Caspian Seas. During the period of spawning, he floats on the Volga, Dnieper and Danube. For these fish it is tending to change the habitat and go to the depth. A characteristic difference of beluga is the absence of a skeleton that replaces the flexible chord.
The spike represents the sturgeon family and has a large commercial history. She inhabit the pools of the Caspian, Black, Aral and Azov Seas. Fish can reach a length of about 214 centimeters weighing up to 30 kilograms. The reserves of this fish are greatly undermined due to the uncontrolled use of smooth networks and chipping nets.
Sterlet is considered one of the most ancient species of fish of the sturgeon family. According to some reports, they appeared in the Silurian period. It is considered valuable commercial fish, however, due to a strong reduction in their number, their fishing in the natural environment is strictly prohibited and punishable by legal. It is found in rivers that fall into the Black, Azov and Caspian Seas.
Siberian sturgeon was described in 1869. This is a freshwater representative, who is the endemic of the Siberian rivers. He lives in lakes and rivers such as Ob, Kolyma, Baikal and Zaysan. These fish can reach a length of up to 3 meters weighing about 100 kilograms. As a rule, the size of the Siberian sturgeon depends on the rivers in which it lives.
The Sakhalin sturgeon is a very rare and poorly studied fish, which inhabited the territory of the Japanese and Okhotsk seas, as well as the Tatar Strait. For some time, the Sakhalin sturgeon spawned in the rivers of Khabarovsk, Primorye, China and Sakhalin. Merciless fishing brought this kind of fish to almost complete destruction.
Russian sturgeon is a rather overall representative who can weigh about 25 kilograms. Larger individuals are also found. The habitat of this fish is limited by the basins of the Azov, Black and Caspian Seas. The fish prefers the receiver lifestyle, because there it is located enough food.
Amur sturgeon, or shrenka, is a freshwater fish, which is a close relative of the Siberian sturgeon. The size of this fish can reach 3 meters weighing up to 190 kilograms, but most often individuals weigh no more than 80 kilograms. At the moment, the Amur sturgeon is on the verge of disappearance and lives in the Amur River basin.
Atlantic sturgeon is a passage fish of the sturgeon family. Adults live on the coastal shallow water of the seas and eat various bottom invertebrates. At the moment, the Atlantic sturgeon has almost disappeared the appearance, which was distributed on the territory of the coast of Europe. To date, he meets only in the Black Sea and the Bay of Biscay.
Lake sturgeon is considered a rather large representative of the genus, which has some similarities with a stupid sturgeon. The most dimensional fish reached 2.74 meters with a weighing of 125 kilograms. This representative lives in the system of great lakes, as well as in the basins of the Mississippi rivers, Saskachevan and St. Lavrenty. At the moment, the number of fish is not concerned.
Persian sturgeon is a passing fish that is on the verge of complete disappearance. The largest fish weighs 70 kilograms from a long body up to 2.42 meters. This species is found in the middle and southern regions of the Caspian Sea. The spawning ground is located in the rivers of the Urals, Kura, Volga, Rioni and Inguri. Persian sturgeon feeds by bentos and small fish.
Lopatonos is a whole kind of radiant fish of the sturgeon family, which reaches about 60-90 centimeters of body length with a weight of not more than 4 kilograms. In the United States, this fish did not receive commercial importance. The natural habitat is the fresh waters of North America. The name “Lopatonos” is associated with the wide and flattened snout of fish of this kind.
The strokes differs from other representatives of the family with its appearance, which is represented by a very long nose that occupies about 2/3 of the head, and the presence of short antennae. In its size, the fish reaches about 7-10 kilograms. At the moment, the habitat of the Sevryuga is the western coast of the Caspian Sea.
Bester’s fish turned out as a result of crossing the beluga and sterlet, which relate to representatives of the sturgeon family. This fish can reach a body length of about 2 meters with a weight of not more than 30 kilograms. The appearance of the Bester is similar to sterlet and beluga at the same time. At the moment, a nonsense is actively grown in fish farms.
The structure and skeleton of sturgeon fish
Representatives of the sturgeon family have an elongated body shape, in which there are 5 rows of solid spikes formed by bone tissue. Two rows are in the belly area, two more rows are side by side, and the last row on the back. The gaps between the rows are filled with bone plates, which perform a protective function.
Sturgeon are characterized by elongated and coneshaped snouts, which has the appearance of a shovel. On the bottom of the snout is a mouth with four mustache and fleshy lips. The jaw itself has a drawup shape, but there are no teeth on it.
The fin on the chest has the shape of a spike with a thickening, and the fin on the back is shifted closer to the tail. The floating bubble is connected to the esophagus and is located below the spine. The most remarkable feature of sturgeon fish is the presence of cartilage and invertebrate chord instead of a skeleton. In the area of the throat near the fish there are membranes of the 4th gills, as well as 2 subordinate gills.
The territory of distribution
Sturgeons are divided into freshwater, semipassage and passage. Passing fish spend part of the time at sea, and part in the rivers. Migration in passing fish is associated with the period of spawning. Semi-costing fish live in coastal zones of the seas or in seas-items. During the period of spawning, migrated to rivers. Most freshwater sturgeons are not subject to longterm migrations, but prefer a settled life in rivers and lakes.
The natural habitat of sturgeon is the northern-wise belt of Europe, as well as the northern range of North America and Asia. However, in connection with evolutionary development, sturgeons began to adapt to inhabitation in moderately-climatic zones. They easily tolerate low temperatures and can do without food for a long time.
On the territory of Eurasia at the beginning of the 20th century, the sturgeon reached an unprecedented scale, when the number of fish caught was larger than in other countries together. For this reason, despite the high fertility of the sturgeon, the number of fish has significantly reduced. With the beginning of the 21st century, in the providence of almost all sturgeon fish in Eurasia, it is strictly prohibited.
However, many farmers and fishing networks have got off to grow these fish on their own. You can do this using several ways. Consider each of them in more detail.
Growing in cages
This method is the most common and profitable. Most fish adapt to life in special cages, where they are feeding. Depending on the size of the fish that must be diluted, they choose a special container with common cells. Garden lines are installed in reservoirs in which the fish should live. However, it is important to remember that small cells can overgrow, so it is necessary to use protective impregnation of networks. As a cage, a model with walls from Delhi with a diameter of cells is used at least 10 millimeters.
The main advantages of this method of growing are that the feed base is a reservoir in which phytoplanktons live. The convenience is also that all the products of the life of the fish will be washed naturally.
Breeding in Uzv
This method is considered a little more costly, since it will be necessary to purchase special equipment. Uzv is deciphered as an installation of closed water supply. In addition to the pool for breeding fish, it will be necessary to buy a filtering system and a friend equipment in the form of automatic feeders. The degree of growth of sturgeon depends on proper nutrition. The food should be bottom and well swelling in the water. The composition should contain substances such as fats, fiber, phosphorus and lysine.
The easiest way to breed sturgeon in ponds, since there is all the necessary feed base, as well as oxygen. The only problem will be control over the growth and state of individuals. In general, the most optimal option is still garden fishing.
Sturgeon milk benefit
Fish milk is caviar contained in males. From a scientific point of view, milk is male seed glands. In mature males, it is painted white, and therefore it was called “Milks”. Fish milk contains fullfledged proteins, which are very useful and nutritious. Their benefit is due to the presence of omega-3 fatty acids, which, when entering the body, have a beneficial effect on the cardiovascular system, preventing the development of heart attacks and strokes. In the milk of sturgeon fish, the concentration of omega-3 is very high.
Fish are noteworthy and the fact that sodium salt of DNA is distinguished, which is actively used in medicine as an immunomodulator. The main goal of this substance is to increase human immunity. Also, sodium salt (or derinata) is perfectly fighting inflammation and stimulates blood formation, contributing to the rapid healing of wounds and ulcers.
In order for sturgeon milk to be not only useful, but also tasty, they need to be prepared correctly. The fastest dish is to panning and frying. However, in addition, from them you can make pancakes, salads, pies and much more.
Sturgeon meat contains vitamins such as B, A, C, PP, as well as a number of useful elements in the form of potassium, calcium, magnesium, sodium, chlorine, nickel and iodine. The sturgeon meat itself is considered delicious, and its regular use has a beneficial effect on the vessels and the cardiovascular system, lowering the level of cholesterol and reducing the risk of myocardial infarction occurrence.
Puberty at sturgeon occurs quite late. Males become sexually mature only at the age of 5 to 18 years, while females ripen by 8 21 years. The ripening period can fluctuate depending on the habitat of the fish. As a rule, northern representatives ripen much later.
Propagation in sturgeons does not occur every year. Spawning of females can occur once every 3 or 5 years. Males at one time spawn much more often. It is also noteworthy that after spawning, males do not die, while this is characteristic of many fish. The migration period of passage and semipercent sturgeon lasts from spring to midautumn. The peak is in the summer. Rivers with a strong current or rocky bottom at a depth of 4 to 25 meters usually act as spawning. A sharp increase in temperature can adversely affect the development of eggs.
Caviar throwing is carried out on the crevices of the bottom or on large stones. One female is able to postpone several million eggs, which make up about 25% of her body weight. Pacific sturgeon produces the largest caviar, the diameter of which reaches 4.5 millimeters. The sturgeon caviar itself is very adhesive and holds well on the substrate. If the water temperature is at the level of +20 degrees Celsius, then the period of embryonic development lasts an average of 2-4 days. Under other conditions, the duration can reach 10 days.
Newborn sturgeons are poor in vision. They are also quite poorly staying on the water, so they hide in special shelters, which are stones. After two weeks, the sturgeon dissolves the yolk bag, which serve them as food. During this period, fry reaches the size of up to 2 centimeters and begin to eat actively. At first, planktonic crustaceans act as the main food, and after scenes, oligoeds and gammarids. Having gained enough weight, young passing species floats to the mouth of the rivers, where it is delayed for a short time. Fry such sturgeon as a spike and Russian sturgeon are delayed in fresh river water, where they remain for a year. Sea water can be destructive for them, so they move there at a later age.
Sturgeons grow quite slowly. Large species aged 2 years reach no more than 35 centimeters in length. At the age of 4 years, their growth becomes more twice, and from 8 years they can reach one meter of body length.
The main diet of most sturgeon fish are bottom organisms and fish. The composition of the diet may vary depending on the age and the habitat of the fish. Adult sturgeons feed mainly with protein foods, and during the spawning period they eat almost everything that can be found at the bottom. As a rule, these are crustaceans, insect larvae, mollusks, shrimp, mussels and leeches.
Sturgeon fry prefer zooplanktons and small worms. Already grown individuals begin to eat shrimp, snails and insects.
At the moment, there are about 17 varieties of sturgeon in the world. Almost all of these fish are at risk.