Sharks
Sharks are one of the most formidable inhabitants of the ocean. The lack of bone tissue and Gill covers, especially the structure of scales, and many other features of the…

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Fish of the Black sea
The fish fauna of the Black sea is peculiar. The class of fishes that includes about 20 000 species, is divided into two sharply distinct branches — the cartilaginous and…

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Predatory fish Piranhas
Piranha — all species of freshwater fish of the family of tetras that live in the rivers and reservoirs of South America. The word “piranha” has its roots from the…

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Sharks

Sharks are one of the most formidable inhabitants of the ocean. The lack of bone tissue and Gill covers, especially the structure of scales, and many other features of the structure speak of their ancient origin, as confirmed by paleontological data the age of the first fossil remains of sharks is determined approximately 350 million years. Despite the primitiveness of the organization, shark — one of the most perfect predatory fish of the ocean.

Over a long period of existence they managed to adapt perfectly to life in the water column and now successfully compete with bony fish and marine mammals. Unlike bony fish sharks and rays don’t spawn and lay their large, covered with a Horny shell eggs or give birth to live young.

The highest values reach whale (up to 20 meters) and the so-called giant shark (up to 15 meters). Both these and others, like baleen whales, they feed on planktonic organisms. Wide and gaping jaws, these sharks move slowly in the midst of clusters of plankton and filter the water through Gill openings covered by a network of special outgrowths of surrounding tissue. Giant shark profiltruyte an hour to one and a half thousand cubic meters of water and remove all organisms larger than 1-2 millimeters. Continue reading

Australian bull shark (Heterodontus portusjacksoni)
Australian bull shark (Heterodontus portusjacksoni) with a glance at her, or rather on her face that produces an even more sinister impression than the white or tiger sharks. However, the…

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Nitrogen metabolism in the aquarium
Nitrogen metabolism in the aquarium: (1) Forage (2) NH 3 . (3) NO 2 . (4) NO 3 . (5) H 2 O. (6) Lighting, (7) Fertilizer (8) O 2…

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