Catadromous and anadromous fish species: their features and habitat

The world of the inhabitants of the seas, oceans, rivers, lakes is very diverse. Scientists have about 12,000 fish species in the saline environment, and close to 6,800 specimens in freshwater reservoirs. Often, many species of fish migrate regularly: from rivers to the sea, from the sea to the rivers. Some do this once a year, some daily. Why do we need such a move and what kinds of migrating living silver is divided into? Many have heard of anadromous, catadromous and transboundary fish species. About them and will be discussed in the article.

What you need to know about migratory fish

Migratory (migratory fish) differ from non-navigable ones because they have the ability to swim for some time in the seas, and another half - in the rivers flowing into them. Some migratory fish easily switch to a freshwater habitat (anadromous fish species), while others migrate to marine (catadromous individuals). Many for such transitions cover large distances. Such movements are associated either with the production of food, or with reproduction.

Anadromous and catadromous fish species have their own peculiarities associated with a change in the salinity of water. When migrating, such individuals seek favorable conditions for the development of fry, food for nutrition. When going from one environment to another, a lot of energy is expended and there are all kinds of obstacles: waterfalls, rapids, high-speed current. For this, adult feeders need to accumulate reserve substances in the form of fat. Many migrating fish wait for death after spawning, and some can spawn repeatedly in this way. Such fish are an important target for human fishing and nutrition for some animals.

Known Anadromes

The anadromous species of fish for spawning from the marine environment moves to freshwater. The most prominent representatives are salmon, herring, sturgeon. The most striking example is the salmon of the Pacific Ocean. Adults can weigh 6 kg and have a length of 60 cm. Spawning spends in the rivers of the Japanese peninsula, Primorsky Krai, Kuril, Sakhalin. This species is born in river water, then the species swim out into the sea, where they spend from 1 to 6 years. After that, they return to their original habitat, spawn and die. It should be noted that this movement occurs against the flow of rivers.

In the Black and Azov Seas there is also an anadromous species of fish, for example herring. For migration, they swim in the deltas of European rivers. Anadromous swimmers are made by sturgeon, lamprey and carp. List of anadromous species of fish is replenished by alozes, trout, and three-spined stickleback. Of the known carp representatives it is possible to call red-peaks-ugai.

In addition to salmon, a rare representative is the lamprey. It occurs in the deltas of the Volga. It spawns in stony and sandy shallows. A very famous anadrom is stellate sturgeon. She lives in the basins of the Black, Caspian and Azov Seas, laying eggs in the Volga, the Urals, the Kura.

One more anadromous specimen of the Black and Caspian seas is a thorn. He can not leave the river for several years. This species also includes keta, salmon, nelma, white fish. Some fish make daily migrations to rivers for surface feeding (at night), and in the daytime they return to the salty environment.

Representatives of the catadromes

The brightest representative of catadromous individuals is the family of eel (eel). Its eggs can travel in the open ocean for months and even years. Then they are referred to the European shores, where they swim into rivers and begin their development. Acne loves a strong current, muddy or sandy soil. It is very difficult to notice it, in the afternoon it hides in burrows or under stones. With the coming of the night, he leaves his refuge. The European eel spends most of its life in a freshwater environment.

Transboundary fish

Individuals living in the same halo, a single economic zone, are called transboundary. In general, these include semi-migratory fish that live in a saline environment adjacent to rivers, and spawn in fresh water. To them it is possible to carry bream, carp. In the Azov and Aral seas, the Northern Caspian, there are pike-perch, ramming, roach.

Anadromous fish species of the Caspian Sea

The living world of the Caspian basin amazes with its diversity . There are very small gobies and giant representatives - beluga. Salmon and lamprey, entering the Kura for spawning, often die from exhaustion. To the anadromous fish of this pool are the following species: salmon, white salmon, stellate sturgeon, thorn, sturgeon. The sea of pike perch, pike, catfish, carp, silver carp and white cupid fell in love.

Sturgeons are not very large here, but there are individuals that have lived more than 30 years. Some stellate sturgeons in the Caspian reach 40 kg of weight. But salmon in this sea come across less and less. An important fish for catching here is the pike. A significant part of the catches are red-rills, which are found on shallows covered with dense vegetation.

Protection of migratory fish

Fish breeding plants have acquired great importance for the protection of many species of migratory fish. Such plants are most often built near dams, in the mouths of large rivers. Females are caught and artificially inseminated. After the selection of eggs, it is kept in special ponds. After the fry grows, they are sent to special reservoirs or rivers. In Russian hatchery plants, billions of young fish are grown annually. Thus, the most valuable anadromous species of fish are reproduced and restored: sturgeon and salmon. Some are involved in the cultivation of pike perch and whitefish.

Russian fish farms of the Volga and the Don have established production of adapted fish: bream and carp. Fry at such plants are fed with natural or synthetic fodders.