In fresh water
Water of streams and rivers, which in addition to rain, constantly being updated from glaciers and snows of the mountains are very rich in oxygen, which is necessary for animal life.
Fast and cold mountain streams are natural habitats for Trout , capable, because of its shape of body and strong muscles, to defeat the resistance of the water.Greedy predators, feeds on larvae, worms and eggs of aquatic animals: catching and holding prey with sharp teeth and then swallows it whole.To reproduce,it enters the water stream crossing even small waterfalls until it reaches the shallower and colder waters with lots of oxygen.Female digs a hole into which she lays 1000-2000 eggs that she leaves, after being fertilized by a male.Egg shoots after 45 days: they don't have mouth, but feed on the yolk of the egg, which is located in a belly bag.They remain motionless at the bottom until they open their mouth and eat the yolk, then come to the surface to feed on plankton.
Fast and cold mountain streams are natural habitats for Trout , capable, because of its shape of body and strong muscles, to defeat the resistance of the water.Greedy predators, feeds on larvae, worms and eggs of aquatic animals: catching and holding prey with sharp teeth and then swallows it whole.To reproduce,it enters the water stream crossing even small waterfalls until it reaches the shallower and colder waters with lots of oxygen.Female digs a hole into which she lays 1000-2000 eggs that she leaves, after being fertilized by a male.Egg shoots after 45 days: they don't have mouth, but feed on the yolk of the egg, which is located in a belly bag.They remain motionless at the bottom until they open their mouth and eat the yolk, then come to the surface to feed on plankton.
In its middle stream the river becomes slower, the coast is covered with vegetation and sandy and rock bottom have dense growth of aquatic plants.There lives Pike, a fish that can reach a weight of 20 kilograms.It has the typical characteristics predators, it swims fast and it's sharp in pursuit of prey.Namely, it has the strong tail and huge mouth full of sharp teeth.But often, rather than to follow the prey it remains hidden among water plants and if any fish or insect passes by it attacks suddenly.It will even eat its youngsters if its hungry.
Without scales and with the appearance of a snake, Eel lives in fresh water from all the world, but when the time comes to mate it prefers the salty sea water.Eel raised in European fresh waters crosses a great way from 6-700 kilometers across the Atlantic Ocean, to Sargasso sea, along the coast of Florida.After laying eggs eel dies, but the hot waters of that see have an ideal environment for its miniature larvae, measuring several centimeters, allowing the Gulf Stream to carry them.That's how they start their journey to zones where their parents lived and they need 3 years to get back to Europe. When they get to the shore, they turn into small eels, and than go to rivers where they will live 5 to 8 years before they start the long trip to mate and die.
|
|
In the final parts of its course, sweet river water is mixed with sea salt.there lives Catfish, that has always aroused the imagination of people.It's present in the depths of Swedish and German lakes, in the Danube and its tributaries, a few years ago even in Po, where it was brought by a fisherman who did not count on the consequences of his actions.
|
Namely, catfish, using its size, is a fish exterminator.Someone was able to, after long-term challenge, get away samples long over 2 meters, but it says that it can reach a length of up to 5 meters and a weight of 300 kilograms. Flat and massive head with a huge mouth, long whiskers on the muzzle and a long sticky body give him a demonic look.Large predator goes hunting at dusk and at night.When the moment comes, male on muddy bottom prepares a nest in the which the female lays eggs.Then he oversees, and when the time comes, protects young floating slowly above the nest, like a large black shadow that no one is allowed to get close to. |
Where the waves are breakingMore than a third of the earth is covered with oceans and seas, a huge amount of water necessary for life.Marine conditions offshore are the most suitable for the development of aquatic life: sunlight penetrates into the water suitable for supporting the growth of dense vegetation, algae, which makes life of animals that feed on them, and which are the food of other animal predators.
In the shadow lair or underwater cracks, hide crustaceans, octopus and his skin that melts into environment making it invisible, and fish such as moray. |
Shark empire
The shark, as a rule, lives in the open sea, and since it has elongated, hydrodynamic body with well-developed fins, swim very fast, although different from all the other fish.in fact, they are moving by rowing with fins, while sharks swim undulating whole body and giving the speed with tail.Cartilage fish, therefore and sharks, have no air bubbles and so that they do not sunk they must continuously swim: they get pressure on the top of the lower tail, of the pectoral fins and from the lower part of the head.In hunting they are guided by the smell and the nervous system that is very sensitive to vibration and changes in water pressure, more than by vision.
|
Ray is very flat fish that with prospect merges with the ground. Some species have a long dorsal spines that can inject a powerful poison. Mouths, are on the belly side, have many sharp teeth.
|
Among sharks there are peaceful species that eat plankton, such as the huge whale shark, with is 15 m long and weighing 13 tons is the largest fish in the world, regardless of its intimidating appearance is completely harmless.But there are also a passionate carnivores predators such as white shark with teeth sharp as the blade, which never wears out and that immediately grow back if some get lost accidentally.Sharks reproduce by eggs: some of them are laid on the bottom, anchored between algae and rocks, with other, the eggs develop in the mother's body, which then brings into the world already formed young.
|
|