Analysis of piscicultural-biological results of works with Russian sturgeon brood fish at the sturgeon hatchery “Lebyazhy” (Astrakhan region, Russia)
AbstractThe state of world stocks of sturgeons is on the edge of catastrophe. These species are either extinct or under threat of extinction under human impacts. At the same time, there are enterprises, fish hatcheries, which deal with restoration and replenishment of natural stocks with of endangered fish species. One of such hatcheries is the sturgeon hatchery “Lebyazhy” (Astrakhan region, Russian Federation). The aim of the study was an analysis of piscicultural-biological features of the Russian sturgeon brood fish. During the study, which was conducted in April–May 2011, 34 Russian sturgeon females were used in two rounds, 17 individuals each. For stimulating gametes maturation, the Derzhavin’s physiological method was used. Caviar was obtained by stripping the eggs under strict hygienic and sanitary norms. Eggs fertilization with the semi-dry method used the male milt that bought at the “Raskat” LLC. Egg stickiness elimination was performed with the aid of talc and apparatuses for the egg stickiness elimination. Eggs incubation was performed in the “Osetr” apparatuses until yolk-sac larvae hatching. The domesticated fish were subjected to bonitation for determining their readiness for spawning. As a result of this bonitation, the brood fish were separated into two groups: first round of rearing works: females with mean weight of 34.8 kg and age of 9 years; second round: females with mean weight of 32.3 kg and the same age. Among injected females of the first round, 100% positive reaction for the stimulating injection was observed, but 95% – among females of the second round. Maturation time of females of both rounds varied from 25 to 30 hours. The maturation state of gametes of sturgeon females or males was determined based on samples obtained. 90.2 kg of eggs were obtained from females of the first round. At the same time, the maximum quantity was observed in the female of 50.5 kg – 9.2 kg of caviar, and the least quantity was obtained from the 27.8 kg female – 2.8 kg. On average, 5.3 kg of eggs were obtained per one female of the first round. The obtained quantity of eggs in one gram did not exceed 48 eggs that are considered to be within normal limits. 79.8 kg of eggs were obtained from females of the second round of rearing works that is 10.4 kg less in comparison with the results of the first round. On average, 5.0 kg of eggs were obtained from one female that is related to less mature fish used in the second tour. At the same time, the maximum quantity of eggs, 7.9 kg, was obtained from a 32.5 kg female, while the minimum quantity, 2.6 kg, from a 20.7 kg female. The obtained quantity of eggs in one gram did not exceed 44 eggs. Mean working fecundity of females of the first round was 198.2 thousand eggs, while it was somewhat less in the second round – 184.6 thousand eggs that did not exceed the normative values.
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