Among the dolphins in the habitat are two species – living in the oceans and living in the seas. They differ mainly in the depth of immersion and food preferences. In our country dolphins are found in the Black and Baltic Seas.
In the middle of the 20th century. The Black Sea was inhabited by a huge number of dolphins. According to rough estimates, the livestock included 2.5 million individuals. But the development of industry, the pollution of sea water by sewage resulted in the gradual extinction of dolphins, since they can live only in clean water. Not the least role in the mass death of dolphins played their industrial production.
Prior to the ban on the massive capture of dolphins, it was conducted with the help of special networks that maimed animals. In the waters of the North Atlantic, there are two rare species of dolphins – white and white.
The white-dolphin reaches a length of 2.7 m, and the females are somewhat larger than males. From the white-marinated dolphin is characterized by shorter pectoral fins and a distinct white stripe on the sides. The white-headed dolphin “Beak” and the front part of the “forehead” are white. The body length does not exceed 3 m. The pectoral fins are well developed (up to 0.6 m in length).
White-fleece and white-fronted dolphins are found mainly in the Barents Sea, sometimes they enter the Baltic Sea. Their number in
Russia is not established, outside the country live in the Norwegian and North Seas. The fishery was preserved only off the coast of Norway. In the Russian territorial waters, both species are protected. The feeding diet of dolphins consists of bottom and bottom fish (cod, flounder, navaga), mollusks and crustaceans they feed less often. Dolphins-blondes are very fond of accompanying sea vessels. Getting into the stream of water from the screws of the ship, they develop a speed of up to 6 km / h. On the shallows are frequent cases of “drying” of white-whitened and white-fronted dolphins.