Biotechnology of reproduction and cultivation of fish stock of Balkhash marinka (Schizothrax argentatus) in industrial conditions

Abstract

Artificial reproduction is one of the most popular ways to preserve rare fish species. Researchers of the Balkhash branch of the Research and Production Center for Fisheries of the Republic of Kazakhstan carried out the reproduction and cultivation of Balkhash marinka at their own fish farm using a recirculating water supply system. There have been considered the technological methods of removing the marinka spawners from the natural environment, their pre-spawning maintenance in fish tanks, hormonal stimulation of spawning, intravital methods for selecting reproductive products, artificial insemination, incubation of eggs, growing viable material for stocking a native reservoir. The catch of the required number of spawners was carried out from the river Tokyraun (Northern Balkhash). After adaptation and quarantine, female species were exposed to 2x and 3x hormonal stimulation with acetonated carp pituitary. Males were injected once. Reproductive products were obtained from a female injected 3 times, after 15 hours; from a female 2x injected – after 21 hours. Duration of insemination for marinka was 2 minutes. The degluing process lasted 40 minutes with constant stirring and partial replacement of the solution. The eggs were incubated in Weiss apparatus, completely protected from light. With a high quality of reproductive products, the fertilization of eggs was 90%. The incubation time at a water temperature of 19.5-20.0 °C continued 3-4 days (60-78 degree days). The yield of prelarvae made 19-20%. Under industrial conditions, keeping the larvae lasted 4-5 days. When feeding marinka larvae, in order to increase their survival, it is advisable to use only decapsulated Artemia eggs. The juvenile period of development of Balkhash marinka began on the 30-35th day. Aller Aqua dry food was gradually introduced into the diet of fry. Under optimal abiotic and biotic conditions, the fry growth rate reached 0.075 and 7.32%/day. At the end of September marinka underyearlings with an average weight of 11.0 g were released into Lake Balkhash. The research results will serve as a theoretical and practical basis for the development of adapted technologies for the artificial reproduction of rare and endemic fish species and their introduction at fish farms.