Evolutionary advantages over fish jellyfish on closer inspection are not as obvious: the structural features of the body and the way to hunt jellyfish make their closest competitors planktivorous fish, and even a slight imbalance between jellyfish quickly gain the upper hand.
At first glance, the jellyfish as predators can not compete with the fishes. Fish active and moving quickly, can see their prey and pursue it, all of this jellyfish is not available. Yet somewhere in the oceans observed paradoxical situation: jellyfish supplant fish feed on plankton. An international team of zoologists, the advantages and disadvantages of jellyfish with a mathematical model which has come to the conclusion that we were still underestimate.
For the study, data were collected on more than 600 species of fish and jellyfish, scientists took into account parameters such as the efficiency of energy metabolism, speed, body size, etc. In the end it turned out that the speed and agility of fishes in efficiency do not give as much of a strong advantage over type of organization jellyfish. Last swim really slowly, but at the same time and energy spent little and undeveloped vision allows them to ignore the visibility of production. Jellyfish can hunt even in the dark, which can not relying on sight fish.
Huge body of jellyfish, in fact, is a shaky gelatinous mass of organic substances, highly diluted with water. 96% of the water contained in the body, and the stinging cells of jellyfish do not too tempting prey for other predators. A small amount of organic matter not that really requires a lot of effort when compared with the fishes. Finally, an impressive body size can cover a large area, and contribute to the pulsating motion pumping water through a network of tentacles. Active hunting and bustle jellyfish prefer to say, in direct contact with the victim and increased their size. Article researchers with the results published in the journal Science.
By themselves, the jellyfish can not prevail over the fish, but they can take the place of the fish where the position of the latter deteriorated. Impoverishment of fish populations due to intensive fishing off the coast of Japan, in the north-eastern United States, in the Black Sea and the Mediterranean shifted the balance towards jellyfish. This gelatinous predators worthless supplant such as anchovies and sardines from the ocean. Therefore, as emphasized by the authors, one should be especially careful with the biological equilibrium in the ocean: the jellyfish watching our every move and do not miss the chance to leave the sea without fish.