The Number – Cypriniformes
Family – Priniv
The genus/Species – Serrasalmus nattereri
Length: average 20 cm, in some species up to 50 cm.
Mass rarely exceeding 1.5 kg.
Caviar: a few thousand eggs.
The incubation period is 10-15 days, depending on water temperature.
Habits: constant float huge flocks.
Food: primarily fish; attack mammals, floating or come to the waterhole, and birds.
18 known species of piranhas, 4 of which are dangerous to humans, although fatal cases have been identified. Continue reading
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