Rearing sterlet (Acipenser ruthenus Linnaеus, 1758) larvae in non-traditional periods

Purpose. To determine major aquaculture-biological parameters of rearing sterlet until viable stages during non-traditional early spring period. Methodology. Mature sex products of sterlet were obtained during a non-traditional fish breeding period (March) from brood fish grown in floating cages in a water body with a natural temperature regime. The weight of sterlet females was 2.6-3.1 kg (2.8 kg on average). Artificial reproduction of sterlet was carried out using methods generally accepted in sturgeon culture after special temperature adaptation of brood fish in a recirculation water supply system. Sterlet free embryos were held with a stocking density of 5–7 thousand ind./m2 in “ICA”-type tanks with an area of ​​4 m2. Sterlet was grown in the same tanks to viable stages with a stocking density of 1.5 thousand ind./m2. Larvae were fed with Artemia nauplii, followed by transfer to the consumption of artificial feeds of recommended formulations. Determination of fish breeding parameters and physicochemical parameters of the environment was carried out using conventional methods. Findings. During the egg incubation period, the rate of development of sterlet embryos at the stages of gastrulation was 87.2% on average. Larval survival during the period before switching to active feeding was in the range of 51.3-67.2%. The yield of sterlet fry at the end of the growing period, which lasted 42 days, was 61.3-73.8% with an average fish weight of of 1.6-1.7 g. It was found that the experimental groups of fish did not differ significantly from by growth and survival parameters from sterlet offspring obtained during traditional spawning periods with other technological schemes of modern sturgeon culture. Originality. Peculiarities of rearing and the level of viability of sterlet offspring of sterlet obtained under factory conditions during non-traditional fish breeding periods were studied. Practical value. The study results are of interest for the development of modern aquaculture methods for sturgeons in the conditions of industrial fish farms.