In this article there is a speech that the main fish in reservoirs of rural regions is the crucian. It is characteristic, as a look steady against adverse conditions of cultivation whereas the carp perishes in such reservoirs.
When crossing a male of a crucian with a female of a naked carp there is a posterity of a scaly and linear form – karpokaras. Cultivation of karpokarasevy hydrides which have an attractive trade appearance, gives the chance to increase a ryboproduktivnost to
9 c/hectares in addition.
UDC 639
It is known that the main fish in reservoirs of rural regions is the crucian. As a result of early puberty of a crucian and his high fertility karpovy ponds quickly get littered, causing the intense food competition to cultivated species of fish. At the same time the crucian is characteristic, as a look steady against adverse conditions of cultivation, especially to the low content in oxygen water (to 0.5 ml/l) whereas the carp perishes in such reservoirs. For introduction of a crucian in ikhtiokompleks there is a need for creation of a sterile (fruitless) form of this look by a known method for fish breeding – hybridization.
When crossing a male of a crucian with a female of a naked carp there is a posterity of a scaly and linear form. Linear hybrids karpokarasya are very similar to linear carps.
By researches it is established that in favorable conditions, in comparison with cultivation of a carp, karpokaras on the second year of life can have mass of 400-500 g on the third – 880-1500 g. This hybrid interesting object for use in nespuskny reservoirs with the zamorny phenomena - for sports and farmer fishery.
From six-year females of a carp receive caviar, and from males of a crucian in weight more than 200 g – milts with use of a hypophysial injection. The double dose of an injection is applied to males of a crucian of 1,5-2,0 mg/kg of weight. For fertilisation of 1 kg of caviar of a carp use 5-7 ml of milts of a crucian. Oplodotvoryaemost of caviar of nearly 100 %. For an incubation, the obezkleenny impregnated caviar load in 50 – Veis’s liter device. Amicable vyklev larvae karpokarasya occurs for the third days of an incubation at average water temperature 21,5 ˚. An exit of larvae at level of 96 %. Molod karpokarasya at a stage of a larva to distinguish from larvae of a carp it is impossible.
At control round-ups of vyrostny ponds clear split of hybrids into individuals with scales and low-scaly is noticed.
Appearance of scaly and low-scaly (linear) karpokarasevy hybrids same as at a carp, but lack of short moustaches – the first sign karpokarasya. Growth rate scaly karpokarasya is a little higher, than at the low-scaly.
Histologic researches of development of sexual system karpokarasy confirmed their futility.
Cultivation of karpokarasevy hybrids which have an attractive trade appearance, gives the chance to increase a ryboproduktivnost to 9 c/hectares in addition. Hybrids have economic prospect: their pantophagy and high resistance to the zamorny phenomena in reservoirs gives a guarantee on a stable ryboproduktivnost. Karpokaras – attractive object for sports fish breeding.
(On materials of the magazine of "Tvarinnitstvo Ukra§ni").