PECULIARITIES OF RAISING YOUNG-OF-THE-YEAR EUROPEAN GRAYLING (THYMALLUS THYMALLUS L.)

Purpose. The study was aimed at raising young-of-the-year European grayling and improving the industrial technology with the use of specialized artificial feeds. Methodology. The work on raising young-of-the-year European grayling was carried out in 2014 at the fish hatchery “Lopushno”, Chernivtsi region, during five months (May ? September). YOY were obtained from 22 age-3?4 brood fish, which were kept in ponds of the natural reserve “Synevir”. Culture-biological parameters of brood fish were determined based on Pravdin (1966) method for salmonids. To avoid traumatization of fish, they were kept in the anesthetic “Propiscin” before the collection of sexual products. The condition factor was determined by Fulton’s formula. Findings. The mean weight of brood fish used for spawning was 110 g with the mean body length of 22 cm. Fulton’s condition factor of European grayling was: 1.1 in females and 1.0 in males. Feeding of larvae was as follows: starting feeds ? live feeds (Cyclops, Moina), then the alternation of live feeds and a specialized starting feed for 30 days, and the artificial feed after. Raising European grayling from larvae to young-of-the-year was carried out in trays of different sizes from 0.5 m2 to 4.5 m2, water level in trays was increased according to fish growth from 20 cm to 42 cm. Water supply was 60 L/min, thus the rate of water exchange was from 0.5 to 1.7 times/hour that corresponded to technical norms for salmonids. Mean weight of the young-of-the-year on September 10 was 17.1 g, mean length was 11.8 cm. Originality. Consists in the comprehensive assessment and development of an integral mechanism of scientific principles and methodical recommendations on artificial reproduction of European grayling. Practical value. The results of the work will be used for the works on the reproduction of valuable fish species in aquaculture facilities of the Carpathian region.