The Mediterranean sea is a part of the ancient Tethys ocean, with an area of 2.5 million square kilometers; the volume of water in the sea is about 3.8 million cubic km, and average depth is more than 1.5 thousand meters. In such considerable dimensions of the Mediterranean sea, its fauna is characterized by significant species diversity, but populations of animals of each species is relatively small. This is mainly due to a small number of plankton in marine waters.
In the Mediterranean there are 593 species of fish, of them in Israeli waters, home to 291 species (mackerel, herring, mullet, tuna, dolphinfish, palamidi, horse mackerel and many others). The Mediterranean coast of Israel encountered 4 species of flying fish. Many fish in the Mediterranean are of commercial importance. Continue reading
Red sea (Arabian Gulf), which is a magnet for divers of all countries, has a diverse flora and fauna.
There are about four hundred species of fish and about eight hundred other representatives of the animals. The absolute majority lives in the southern coastal shallows. A third of them live in the Red sea. Until 1869, the opening of the Suez canal, endemic species were much more, but since then the flora and fauna of the Mediterranean and red seas were mixed.
Both on the surface and in depth (over 2800 meters) in the Red sea water has the same temperature. Up to +44° C, which was recorded in 1964. It is not only the warmest, but is also the most salty sea in the world. In one liter of water contains about forty grams of salts. Continue reading
Sharks are color blind
At the University of Queensland examined the eyes of the shark and came to the conclusion that those deprived of color vision.
The research object of scientists were 17 species of sharks. During microspectrophotometric analysis, it was found that 10 of them were no cones, intended for color vision, and their role was partially assumed the highly sensitive sticks. The remaining seven species that belong to three different families, had one type of sensing elements designed to detect wavelengths from 532 to 561 nm.
It is known that whales, dolphins and killer whales also stick with the cones of one type, which is able to recognize green color. Continue reading