The intensive method of fish farming
An important reserve in increasing fish productivity is the introduction of fish culture in the practice of the method of joint cultivation of fishes of several kinds . that most fully use feed resources of the reservoir. Practice confirms the possibility of growing in a variety of combinations that reduce competition for food fish such as carp, carp, white and variegated silver carp, white Amur, etc.
Silver carp . With the introduction into farms of joint cultivation of fishes of the composition of the productivity of fish in ponds is 20 – 30 kg/ha water area. When grown with carp and herbivorous fish in pond farms of the southern areas by herbivorous fish receive an additional fish for at least 6 – 10 t/ ha, in ponds in the forest-steppe up to 3 – 5 kg/ha.
The silver carp eats all types of algae that occur in fresh water. Its power is supplied by filtering phytoplankton through a kind of arranged Gill apparatus. In Biotechnics of artificial breeding using the method of pituitary injections, where to produce offspring using the pituitary glands of fish / kg females. The ripening females after hypophyseal injections depends on the temperature conditions in the spawning basins. When ripe, the prevailing temperature of 21 – 26 degrees Celsius.
White Amur feeds on aquatic vegetation,and terrestrial herbs, pour in a flood or asked in the pond. Most young prefer soft vegetation, but if well hard and consume the vegetation. To aquatic plants include duckweed, hornwort, arrowhead, sedge fibrous, filamentous algae, young shoots of cattail and common reed, etc. From terrestrial plants white Amur eats clover, sorrel, meadow grass, tree leaves, yarrow, etc. If the pond lacks vegetation, he goes to the consumption of other kinds of food, zooplankton, concentrated feed.
The perch is a large predatory fish. Develops well and grows even carp ponds with abundant vegetation. Grown as additional fish in the presence of weed – ruff, bitterling, bleak, loach, gudgeon, verkhivka, bistrenci. Sexual maturity occurs in the second year. To preserve the number of cattle walleye every year is the stocking of individual waters larvae and juveniles potrasenoy. The caviar is delivered to the nests and incubated in water bodies where there is no trash fish which could eat away the eggs.
After 3 to 10 days of incubation depending on the water temperature, the larvae appear length 3 – 6 mm. After 10 to 15 days the length of their body reaches 3 cm At this time they were seated on the spawning ponds, where there is a weed fish. Licina in the age of pike passes to predatory way of eating.
Best walleye grow at a temperature of 18 – 20 degrees Celsius. Juvenile pike-perch grows quickly if in the ponds there is an abundance of food. For one vegetational season weight up to 600 g and more. By the nature of power refers to carnivorous fish. Juveniles during the first months of life feed on zooplankton (Cyclops, Daphnia, insect larvae, bosmina). Further passes to feeding by larvae and fry of fish, small fish (UCLA, char, gudgeon, etc.). Zander constantly hunts for its prey, avoiding areas with thickets and dwells deep in snag pits, quarries, old canals of small rivers, etc.
At joint cultivation of pike perch with feeding in carp ponds upon availability of trash fish (4 – 5 thousand units per 1 ha) of walleye fry are thrown from 200 to 300 PCs./Joint cultivation of perch carp creates the best conditions for its growth, thus increasing the total fish production, including at the expense of perch per 10 – 20 kg/ha. perch Spawn mostly at night when the water temperature 8 to 10 degrees Celsius in places where there is no flow, at a depth of 0.6 – 3.5 m. the females lay Eggs on the roots of sedges, reeds, reeds, willows and other plants in their nests and leave them. Nest guarding males. In natural ponds spawning there, so put up artificial nests in which females lay eggs.
In many fisheries aquaculture fish become sturgeon . Beluga, sterlet, Siberian sturgeon, Russian sturgeon, spike, paddlefish. The main types are the Russian sturgeon and Siberian sturgeon. Siberian sturgeon by way of life are divided into semi-anadromous (live in the Ob and Yenisey), the river (live in Lena, Indigirka, Kolyma, Yana) and riverine, inhabiting lake Baikal and Zaisan. They differ in size, shape, growth rate, time of maturation, length of migration, fertility and other characteristics.
The entire life cycle of Siberian sturgeon held in fresh or slightly salty water. It is characterized with low growth rate, small size, late ripening (15 – 20 years old). On average, Mature producers weigh 2.5 to 3 lbs. sturgeon Grows slowly. Obi five-year fish have a length of 64 cm, at seven years – 97 cm, eight in – 122 cm In the Lena sturgeon at 13 years old weigh about 2 kg. In the Yenisei river sturgeons grow even slower.
Usually a massive move of the sturgeon begins in mid-June, when the water in the river Lena warms up to 12 – 14 degrees Celsius. When lowering the temperature of the spawning run is suspended. Important species the device that provides the optimal mode for vyklevyvanija from the eggs fry in the short Yakut summer are short period of the spawning run. A characteristic feature of the Lena sturgeon is the attainment of sexual maturity at a relatively early compared with the Siberian sturgeon age.