The Red Book is a living reminder to humanity of how thoughtlessly and wastefully it treats natural resources. Each view inscribed on its pages is an occasion to think about the future of the Earth. Today, for example, the question of whether a unique large species of sturgeon, the Atlantic sturgeon, will survive on Earth is very acute. And once he was a frequent guest on the table at rich feasts and feasts.
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The Atlantic sturgeon is a chordate animal from the class of ray-finned fish. It belongs to the large sturgeon family. Latin name of the species Acipenser sturio.
Inside the genus of sturgeons, the species has a special place. Phylogenetic relationships with other sturgeon species have not been fully studied. There is a possibility of having a common ancestor with those species that have about 120 chromosomes (stellate sturgeon). Scientists have not yet established the exact taxonomic status for some populations that have fallen into geographic isolation. Most disputes around the North American sturgeon populationAtlantic, which they are trying to transfer to the species rank.
Types of Atlantic sturgeon
Sturgeon can be anadromous, semi-anadromous and freshwater species. Two forms of the Atlantic sturgeon live on the territory of the post-Soviet space: migratory (anadromous), migrating to rivers, and a freshwater (residential) form that lives in Lake Ladoga.
Habitats
In the old days, the giant Atlantic sturgeon inhabited the North and B altic Seas. Met along the coast of Europe in the Atlantic. Sometimes caught in the Black Sea. The species was considered a valuable commercial fish.
During the spawning migration, the Atlantic sturgeon can enter the waters of the Kaliningrad region, the Gulf of Finland and even the Neva. But he does not live permanently in these places. A single catch was recorded in the White Sea, a large individual was caught near the mouth of the river. Umba. Anadromous species came across in the waters of the Northern Dvina.
The Ladoga residential population has been little studied. It is known that Atlantic sturgeons go to the Volkhov River to spawn. Spawning sites were previously located in the lower part to the rapids.
Appearance
The main feature of the Atlantic sturgeon is its gigantic size. Previously, individuals came across whose body length exceeded 5 meters. Weight at the same time could go off scale for 600 kg. Sturgeons are recognized centenarians, and the Atlantic species is no exception. It is difficult for scientists to obtain accurate data on life expectancy, but the individuals that fell into their hands were from45 to 100 years.
The Atlantic sturgeon differs from its fellow species in the absence of folds formed by the gill membranes below the intergill space. The mouth of the fish is small with an interrupted lower lip, the head tapers towards 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 has many longitudinal bony scutes on its body, called bugs. But it is in this species that their sizes are larger than others. The tail stalk is protected by large shields. There are rhombic bone plaques along the back.
The color of the sturgeon is dim. The body is olive-bluish, some individuals have a golden tint. The bugs are painted lighter than the main body. The lower part of the body (belly) is white.
Features of behavior
Anadromous Atlantic sturgeons migrate from the sea to rivers to spawn. They do not accumulate in large schools, like other fish, but go singly or in small groups. According to the time of reproduction, there are spring and winter forms. Winter sturgeons stay for the winter in fresh water.
Young animals live in the rivers for several years. Juveniles go to sea only when they reach a certain body length (from 60 cm).
Reproduction
The age of puberty for a male comes in the seventh or ninth year. The female matures later, by the age of eight or fourteen (the studies were carried out in the Black Sea). Duringspawning female can sweep several million eggs. Caviar is fixed on the substrate. Embryonic development takes 3-4 days, but the water temperature should be around 20 °C. At lower temperatures, embryonic development is delayed by 10-12 days. At the time of hatching, the length of the larva is about 10 mm. In 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 the larvae are planktonic crustaceans and chironamides. They can eat insect larvae. Adult Atlantic sturgeons eat gerbils and anchovies, as well as invertebrate worms and small crustaceans. Sometimes shellfish are in the diet.
Conservation status and fishing
The Atlantic sturgeon is on the verge of extinction. The number of individuals is very small, today the catch of Atlantic sturgeon is prohibited throughout Europe. Therefore, it is difficult to say what the Atlantic sturgeon is caught on. It's hard to talk about gear too. Only one thing is clear, if the population can be restored, and the catch of the Atlantic sturgeon becomes possible, then this should be a very strong fishing rod with good tackle. Most often, the catch was made by gillnets during spawning migration.
In the old days, a very large Atlantic sturgeon came across. 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 tasty fillet, at that time the fishermen received 80 kg of caviar. In FinnishBay, a large individual was caught in 1934. This fish weighed 177 kg. A significant trophy was also obtained in Lake Ladoga. The caught Atlantic sturgeon was almost 3 m long and weighed 130 kg. From the skin of this giant, a stuffed animal was made, which is stored in the Museum of the Academy of Sciences in St. Petersburg.
The last confirmed catch of Atlantic sturgeon occurred in 1984. A female 1.5 m long was caught, weighing about 30 kg.
Today it is confirmed that the Atlantic sturgeon is preserved in the Black Sea near the Rioni River.
Why numbers are declining
Significant damage to the number of Atlantic sturgeon causes human activities. Dams or dams are built on 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 have not been received anymore.
Man discharges industrial waste into rivers and seas, water pollution affects the number of fish. Spawning grounds for sturgeons are suffering from timber rafting. Trunks accumulate in separate areas, block passages and rot, disrupting the oxygen regime.
At the moment, scientists are puzzled by the cryopreservation of genomes so that they can recreate the species. These works will yield results only with the full cooperation of the countries concerned.
The game "Russian fishing"
You can catch Atlantic sturgeon not only on trophy fishing. Todaythere are online games where you can show your skills in the virtual world. "Russian Fishing" (RR) is a game that even a beginner can easily understand. On the Neva, the Atlantic sturgeon is caught in a special location called the Peter and Paul Fortress. Such fishing allows you to quickly level up in the game without requiring additional expenses.
Tips for beginners:
- If you catch a big fish, drink alcohol and eat fish soup.
- Catching sturgeon is best on a float, so you can get more experience in the game.
- If you caught a small fish, throw it off the line.
If you want to play RR 3.7. (Neva), the Atlantic sturgeon must be caught by you. To do this, you will need to spend about 2 million in-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.
