Where did it come from?
The sea of Azov is one of the youngest seas of our planet, it was formed around the VI Millennium BC as a result of a catastrophic rise in water in the Black sea. Before this, the sea did not exist, and the don river flowed into the Black sea near Kerch. For a long time, Azov was one of the freshest seas, which was provided by the inflow of rivers carrying fresh water. Its salinity was three times lower than that of the ocean.
What kind of fish is found in it
Since ancient times, Azov was considered a "sturgeon Paradise", and the main wealth that was extracted in it was the" Royal" Russian sturgeon, which reached an unprecedented size. In addition, there were a large number of delicious Beluga and Sevryuga, commercial herring, as well as carp fish: rybets and Shemaya, chehon and Azov-black sea Taran (taranka).
Here you can find walleye and bream, crucian carp, bleak, IDE, sterlet. In Azov, sea fish such as flounder-gloss, black sea Kalkan, pelengas, stickleback, needle fish, Hamsa, barabulka, lobans, mackerel, mackerel, marl and mullet gain weight.
The sea is home to more than a hundred species of fish, three species of dolphins (one of them-azovka lives only here. It is the smallest Dolphin in the world) and one species of shark – Katran (dogfish), mussels, Rapana, shrimp and crabs.
In terms of fishing capacity, the reservoir was six times higher than the Caspian, 40 times (!) the Black sea, and 160 times (!) the Mediterranean. It is known that in 1936, 275,500 tons of fish were caught from the Azov sea, and in the early 1960s of the XX century, up to 760,000 tons were caught.
Why was there a lot of fish
The fact is that the sea of Azov is well warmed throughout the entire area and throughout the depth, because the deepest place in it reaches only 13 meters. The largest area of the sea has a depth of about five meters.
The coast of Azov is flat and the bottom of the sea reaches a depth of five meters only two kilometers from the surf line.
In the Taganrog Bay, the water depth varies at the level of 2-3 meters and only on the border with the sea, the bottom drops to 8-9 meters.
In addition, in Azov there are a number of bottom elevations-these are Zhelezinskaya, Morskaya and Arbatskaya banks, the water column above which is three meters.
Thus, the thickness of the water is well warmed and illuminated by the sun, which gives life to plankton, small crustaceans and algae, which are the main food for fish. In addition, rivers bring here nutrient-rich silt, which is collected from a water intake area of 586,000 km2.
The average annual temperature of the Azov water Is 11°C, in summer it warms up to+24–+26 the temperature in the bottom layer is from + 20 to + 22 °C.
What's wrong with the sea of Azov
But all this may be a thing of the past due to sea pollution and uncertain legal status. Since 2004, the status of the sea was determined by the agreement on cooperation between Russia and Ukraine, but now Ukraine has unilaterally withdrawn from it.
Now the data of catches of the XX century seem fantastic. The economic activity of both countries has led to a sharp reduction in the number of fish. This is due to the regulation of the level of the Kuban and don rivers, which led to a reduction in the inflow of clean river water to the Azov, damming fish spawning grounds in the rivers, washing pesticides and fertilizers from the fields into the rivers and taking water from the sea itself, which led to an increase in its salinity.
Now, according to the "Biofile" magazine, more than a thousand enterprises discharge into the sea; the main source of pollution is the Mariupol plants-Azovstal, Azovmash and the Lenin's plant named (imeni Iliytcha). The total volume of runoff is 5,000,000,000 cubic meters per year.
The 2007 storm led to catastrophic pollution, when 2,000 tons of fuel oil and 7,000 tons of sulfur got into Azov as a result of damage to tankers and ships.
By the XXI century, Beluga has disappeared from the sea, it is difficult to catch sturgeon. Because of the increase in salinity, jellyfish appeared that eat fish food.
According to the Association "Ecology and peace", Azov is caused by poaching by bottom trawling, and the borders between Russia and Ukraine on the Azov are not defined, as a result of which Ukraine considers most of the water area its own and is fishing there.