Technological factors in the cultivation of sterlet sturgeon planting material in a recirculation aquaculture system

Abstract

Recently, it has not been possible to engage in natural reproduction of sturgeons in Dagestan, because the spawning rivers Terek and Sulak are regulated, and the passage to the spawning grounds is completely closed by dams. There is only one way out for the restoration of sturgeon stocks it is artificial reproduction through industrialization and the creation of complex, closed regulated fish farms that can function both in the form of small fish farms and in the form of large holdings. The purpose of the work was to study technological factors in the cultivation of sterlet sturgeon planting material in a recirculation aquaculture system. The object of the study was a population of sterlet sturgeon (Asirepseg ruthenus Linnaeus, 1758) – a freshwater fish species of the sturgeon family. The study material was normally pigmented and albino (colored) sterlet with an average initial weight of 60 g. Under the conditions of the Republic of Dagestan studies have been carried out to establish the influence of a complex of biotic and abiotic factors (temperature, oxygen, planting density, feed grade, meat and bone attractant, probiotic Subtilis) on the growth, morphometric indicators and survival of juvenile sterlet sturgeon in the recirculation aquaculture system. The fish-breeding and biological characteristics of pigmented and albino sterlet have been given. It has been established that the design features of the recirculation aquaculture system did not allow to meet the biological needs of sterlet in water. The flow rate of water entering fish tanks was limited to 10 l/min per 1 m³, which provided a water change in 1 hour 40 minutes at a standard of 20–60 minutes. The optimal planting density of sterlet with an initial body weight of 58–64 g under conditions of limited water supply (10 l/min/m³) was the density of 250 pcs. /m³. The effectiveness of using two formulations of compound feed when growing both normally pigmented fish and their albinos showed that the highest fish-breeding indicators were obtained in normally pigmented sterlet when feeding with Sturgeon Grower No. 4 (47/13). The economic effect amounted to 373,5 rubles/m³. In albinos, the highest fish-breeding indicators were obtained when feeding productional feed Sturgeon grower 46/18 with. The economic effect was 285,0 rubles/m³.