The Red Book is a living reminder of humanity about how thoughtlessly and wastefully it relates to natural wealth. Each view inscribed on its pages is an occasion to think about the future of the Earth. Today, for example, the question is very acute whether the unique large species of sturgeon - the Atlantic sturgeon - will remain on Earth. And once he was a frequent guest on the table at rich feasts and feasts.
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Atlantic sturgeon is a chordate animal from the class of radiant fish. It belongs to a large family of sturgeons. The Latin name for the species is Acipenser sturio.
Inside the genus of sturgeons, a special place is assigned to the species. Phylogenetic relationships with other sturgeon species are not fully understood. There is a likelihood of a common ancestor with those species that have about 120 chromosomes (stellate stellate). Scientists still have not established the exact taxonomic status for some populations that are in geographical isolation. The most controversy surrounding the North American population of Atlantic sturgeon, which they are trying to translate into a species rank.
Types of Atlantic Sturgeon
Sturgeon can be a passing, semi-passage and freshwater species. Two forms of the Atlantic sturgeon live on the territory of the post-Soviet space: a passage (anadromous) migrating to rivers, and a freshwater (living) form that lives in Lake Ladoga.
Habitat
In the old days, a giant Atlantic sturgeon populated the North and Baltic Seas. Met along the shores of Europe in the Atlantic. Sometimes I came across in the Black Sea. The species was considered a valuable commercial fish.
During spawning migration, Atlantic sturgeon can enter the waters of the Kaliningrad region, the Gulf of Finland and even the Neva. But constantly in these places he does not live. A single catch was recorded in the White Sea; a large individual caught near the mouth of the river. Umba. Passing view came across in the waters of the Northern Dvina.
The Ladoga residential population has been little studied. It is known that Atlantic sturgeon go to the Volkhov River to spawn. Spawning grounds were previously located in the lower part to the thresholds.
Appearance
The main feature of the Atlantic sturgeon is its gigantic dimensions. Previously, individuals were found whose body length exceeded 5 meters. Weight could exceed 600 kg. Sturgeons are recognized centenarians, and the Atlantic species was no exception. It is difficult for scientists to obtain accurate data on life expectancy, but individuals falling into their hands were from 45 to 100 years old.
The Atlantic sturgeon differs from its counterparts by the absence of folds formed by branchial membranes below the intersternal gap. The fish has a small mouth with an interrupted lower lip, the head narrows to the front and looks somewhat flattened. The role of the organ of touch is performed by two pairs of antennae. The eyes are also small, with a golden iris.
Like all representatives of cartilaginous ganoids, the Atlantic sturgeon on the body has many longitudinal bone scutes, called bugs. But it is in this species that their sizes are larger than others. The tail stalk is protected by large shields. Rhombic bone plaques are located on the back.
The color of the sturgeon is not bright. The body is olive-bluish, some individuals have a golden tint. The bugs are painted more lightly than the main body. The lower body (belly) is white.
Behavior features
Passing Atlantic sturgeons migrate from the sea to rivers for spawning. They do not accumulate in large schools, like other fish, but go alone or in small groups. By breeding time there are spring and winter forms. Winter sturgeons stay for the winter in fresh water.
Young animals live in the rivers for several years. Young individuals leave for the sea only after reaching a certain body length (from 60 cm).
Breeding
The age of puberty for a male comes in the seventh to ninth year. The female matures later, by eight to fourteen years of age (studies were conducted in the Black Sea). During spawning, the female can sweep several million eggs. Caviar is fixed on the substrate. Embryonic development takes place in 3-4 days, but the water temperature should be around 20 ° C. At lower temperatures, embryonic development is delayed for 10-12 days. At the time of hatching, the larva is about 10 mm long. After 2 weeks, the body lengthens to 18 mm, at which time the larvae begin to feed on their own.
What do they eat
In the diet of larvae, planktonic crustaceans and chironamides. They can nibble on insect larvae. Adult Atlantic sturgeons eat gerbils and anchovies, as well as invertebrate worms and small crustaceans. Sometimes there are clams in the diet.
Conservation Status and Fishing
Atlantic sturgeon is on the verge of extinction. The number of individuals is very small, today the catch of the Atlantic sturgeon is prohibited throughout Europe. Therefore, it is difficult to say what the Atlantic sturgeon is fishing for. It's also hard to talk about gear. Only one thing is clear, if the numbers can be restored, and the catch of the Atlantic sturgeon becomes possible, then this should be a very strong fishing rod with good gear. Most often, the catch was carried out by gill nets during spawning migration.
In the old days came across a very large Atlantic sturgeon. Trophy fishing, that is, the desire of fishermen to get the largest representative of the species, gave amazing results. So, in the Neva in 1851, a female Atlantic sturgeon weighing almost 320 kg was caught. In addition to a delicious fillet, at that time the fishermen received 80 kg of caviar. A large individual was caught in the Gulf of Finland in 1934. This fish weighed 177 kg. A significant trophy was also received in Lake Ladoga . The Atlantic sturgeon caught was almost 3 m long and weighed 130 kg. An effigy was made from the skin of this giant, which is stored in the Museum of the Academy of Sciences in St. Petersburg.
The last confirmed fact of the extraction of the Atlantic sturgeon occurred in 1984. A female 1.5 m long was caught, whose weight is about 30 kg.
Today it is confirmed that the Atlantic sturgeon is preserved in the Black Sea near the Rioni River.
Why the number is decreasing
Significant damage to the number of Atlantic sturgeon causes human activity. Dams or dams are built on the rivers. For example, the Volkhov River, into which the Atlantic sturgeon spawns from Lake Ladoga, was blocked in 1926 by a dam. In recent years, data on sturgeons in this river were no longer available.
A person discharges industrial effluents into rivers and seas, water pollution affects the number of fish. Spawning grounds of sturgeons suffer due to rafting of the forest. Trunks accumulate in separate areas, block passages and rot, violating the oxygen regime.
At the moment, scientists are puzzled by the cryopreservation of genomes so that there is an opportunity to recreate the species. These works will yield results only with the full cooperation of interested countries.
Game "Russian fishing"
You can catch Atlantic sturgeon not only on trophy fishing. Today there are online games where you can show your skills in the virtual world. Russian Fishing (PP) is a game that even a beginner can easily figure out. On the Neva, the Atlantic sturgeon is caught in a special location called the Peter and Paul Fortress. Such fishing allows you to quickly pump levels in the game, without requiring additional costs.
Tips for beginners:
- If you have caught a big fish, drink alcohol and eat an ear.
- It is best to catch a sturgeon on a float, so you can get more experience in the game.
- If you caught a small fish, discard it from the fishing rod.
If you want to play PP 3.7. (Neva), the Atlantic sturgeon must be caught by you. To do this, you need to spend about 2 million game rubles. The cost of Lock Fish is 450 thousand for 1 piece, while you will need at least three. A good, powerful reel will cost at least 450 thousand. You can buy bait or catch it yourself.