Watching fish in an aquarium, you’d think they never rest or sleep. In the understanding of man, they are in constant motion. However, like all animals, fish periods of active behavior alternate with phases of slowing of physical functions – this is the dream fish.
Dream fish is different from our understanding of sleep. Structural features and habitat not allow the fish to fall into a state in which they would be completely disconnected from reality. In such a state is immersed most mammals during sleep. The fish also during sleep, the brain activity remains unchanged, – they are not able to fall into a state of deep sleep.
This feature and may cause the issue: how do aquarium fish sleep?
Studying the behavior of aquarium fish, you will notice that at certain times the fish are almost motionless, transfixed in the water. This is the sleeping fish. During sleep, the fish usually drift without active movement. But the slightest influence of external factors leads fish into an active state. Continue reading
Typical representatives of the nekton is the herring. It is well known that this fish has great commercial value. Until comparatively recently, it was promyshlyali in such large quantities that its price was very low, despite excellent taste and nutritional quality. In recent years, due to the sharp increase of the fishing fleet and introduction of intensive methods of production occurred overfishing. The number of herring in the oceans have decreased dramatically.
If in the future the intensity of the herring fishery will increase or even remain at current levels in the coming years, this valuable food fish will become a Museum rarity. Reduction of stocks of herring and concerned consumers and fishermen, but the first sounded the alarm scientists.
The appearance of the herring is well known to everyone, but it is unlikely that the layman can easily distinguish one kind of herring from another: the difference between them for the untrained eye to be insignificant. Species differences are not only in the details of the structure and the size of the fish, much deeper than they differ from each other in biology, numbers, distribution. Therefore, the fishery for mackerel fishes should be strictly subordinated to scientific data, to each type needs special approach. Continue reading
In the Atlantic ocean, the Black sea and off the coast of India dwells amazing and a bit scary fish monkfish .With it is associated a very curious phenomenon. For a long time researchers could not understand why all the water harvested from fish of this species are invariably females. As they multiplied.
Only after the beginning of the heavy deep-sea studies have found out that monkfish has developed a unique mechanism of reproduction. It turned out that the male and female fish monkfish differ in size a thousand times. The female is a large part of his life spent in the coastal zone and can grow up to two meters long, and the male also reaches only a few centimeters and lives at great depths, where is the justice in this world = ( . This was established when he was discovered living at depths of more than two hundred meters tiny fish acerated. Caught deep-sea dredges of acaracide were always males. Only after painstaking research revealed that acerated is (many readers probably already guessed it) a male sea devil, and not a separate species or a subspecies.
To find such a small male helped another feature of the sea devil — the annual migration of huge females on the depth taken by them for the purpose of procreation. Continue reading