Increase in productivity of reservoirs due to additional fish in the conditions of the first zone of fish breeding

The article considers the possibility of cultivation of the hybrid of a common carp and a crucian carp as an additional fish for a common carp. The feature of a carp as a main object of cultivation in pond farming of our country is given. Biological characteristics of a common carp and a crucian carp are considered. It is established that as perspective object of fish breeding the hybrid can be used not only in fisheries but also in reservoirs with severe hydrochemical conditions. The hybrid inherits qualities of both parents, including the growth rate of a common carp and high adaptability to the environmental conditions of a golden crucian carp. Aspects of development of a carp and a hybrid at different stages of ontogenesis were studied. The factory method of reproduction was used in the experiment; larvae were bred in a fish hatchery for 25-30 days. It was established that an amount of viable young fishes of a hybrid was 8.7% higher than that of a carp. After beginning an active feeding, the mortality of carp young fishes was 7.1%, hybrids - 5.8%. In the period of breeding the survival rate of larvae was at the same level. The nutrition of fingerling of a carp and a hybrid was considered, food preferences were noted. A comparative characteristic of the cultivation in an experimental and control pond enables to conclude that the growth rate of experimental groups was depending on conditions of the reservoir. The growth rate of fingerlings of a hybrid in control pond was lower than that of a carp. The weight of carp fingerlings was 28.3-32.8 g., the weight of hybrid fingerlings was 21.7-25.4 g. In the experimental ponds the weight of hybrid fingerlings at the end of the growing season was equal to the weight of carp fingerlings and was 20.5-24.3 g. Accordingly, the hybrids of a common carp and a crucian carp are promising objects of cultivation as an additional fish or as a part of polyculture cultivation under intensive fish farming.