Scientists of the subsidiary organization of the “National agrarian science and educational center” JSC - LLP «Fisheries Research and Production Center» held an online consultation.
Within the framework of this online consultation, a global topic for the fisheries of Kazakhstan was raised, such as the conservation of sturgeon fish species in natural reservoirs, ways of preserving their numbers through the successful development of aquaculture, in particular through artificial reproduction and commercial cultivation, were discussed. The following topics have been discussed with scientist: biotechnical techniques used in aquaculture at the present stage, technological processes and mandatory fish breeding measures that require mandatory implementation when growing sturgeon fish in artificial conditions.
The speaker was Koyshybayeva Saya Kashkinbayevna, the head of the aquaculture laboratory of LLP «Fisheries Research and Production Center».
The natural stocks of sturgeon fish have decreased to a critical level, the only way to restore and preserve the gene pool of these relict fish species is the successful development of aquaculture. The main areas of sturgeon aquaculture include artificial reproduction and commercial rearing. Due to artificial reproduction, natural reserves can be restored, and the active development of commercial sturgeon farming will allow saturating the consumer market with valuable gourmet products, in the absence of natural populations.
Replenishment of natural populations of sturgeon fish in the Republic of Kazakhstan are carried out by sturgeon fish hatcheries in the city of Atyrau, they are engaged in factory conditions of artificial reproduction and raising of young sturgeon fish for release in the Ural-Caspian basin.
Aquaculture farms dealing with sturgeon fish farming solve the problem of supplying products to the consumer market. Today in the Republic of Kazakhstan there are such aquaculture farms as "Karaganda - Sturgeon" in the Karaganda region, LLP "Kazakh - Osetr" in the Mangistau region, LLP "Khalyk balyk" in the Almaty region, the farm "Ardagym" in the Aktobe region, LLP "Royal Fish” in the Atyrau region, etc.
It should be noted that the biotechnology of artificial reproduction of sturgeons in Kazakhstan, due to a sharp drop in the number of producers, requires the formation of broodstock in case of acute respiratory infections. In order to preserve the number of sturgeon fish in a natural reservoir, in addition to strengthening the protection of migration routes during the spawning migration of spawners, allowing spawning migrants to pass to spawning grounds, it is necessary to form the SFF of sturgeon fish taking into account their genetic structure. The composition of RB and released juveniles must match the natural species genetic makeup to ensure maximum survival after release into the Caspian Sea.
To increase the commercial return of sturgeon fish, it is necessary to increase the weighed portions of reared and released juveniles into a natural reservoir, to switch from a standard weighed portion of 2–5 g to 10–20 grams or more. It is also necessary to pay attention to the species composition of sturgeon juveniles released into the reservoir, because at present there are species in the Caspian herd that are on the verge of complete extinction. It is also necessary to strengthen state support for agricultural producers involved in aquaculture. This can be the issuance of subsidies for feed, for the purchase of planting material, for the purchase of sturgeon fish producers, for the purchase of special equipment and inventory, etc.
To increase the number of sturgeon fish, it is necessary to reduce the pressure on natural populations. Despite the moratorium adopted by Kazakhstan in 2010 on the commercial fishing of sturgeon fish in the Ural-Caspian basin, the number of sturgeons entering the spawning river. Ural continues to decline. To preserve sturgeon fish species in the republic, it is necessary to develop commercial sturgeon fish farming. For the successful development of this area, it is necessary to know and implement biotechnical methods of breeding and growing these fish species in aquaculture.
Today, the development of commercial sturgeon breeding is constrained by such factors as the lack of high-quality viable planting material; lack of highly qualified specialists; high cost of complete, balanced, specialized sturgeon compound feed; limited scientific developments on an effective method for the early determination of the sex of fish, on the method of accelerating the maturation of females and shortening the periods of spawning cycles, etc. Development of the accelerated formation of highly efficient herds of sturgeon females for guaranteed obtaining of a valuable gourmet product - edible black caviar, the world market, which is currently satisfied only by 20-25%.
According to expert estimates, up to 35 thousand tons of marketable sturgeon meat and about 650 tons of edible black caviar are produced annually in countries engaged in commercial sturgeon breeding. The main share falls on China, where sturgeon aquaculture production is about 30 thousand tons of meat over 500 tons of black caviar per year.
When artificially keeping and growing sturgeon fish in aquaculture conditions, the main costs are for the purchase of feed for feeding fish. Consumption of artificial feed contributes to the improvement of the immunity of farmed sturgeon fish. Artificial feed is used both imported and domestically produced. Starting compound feeds are used when rearing juveniles up to 5 g, production feeds - up to 25 g and more, RB of sturgeon fish are fed with special feed for producers. Particular attention should be paid to their physical and chemical composition when purchasing artificial feed, especially to the amount of proteins, carbohydrates and fats.
For example, in the compound feeds of the company "COPPENS" (Netherlands), in the starting compound feed, the protein and fat content is 56/16, in the production feed - 46/14.
For the successful cultivation of sturgeon fish in aquaculture, it is imperative to carry out the basic technological processes, which include: feeding fish with artificial feed; sorting and seating fish as they grow; water quality control; cleaning fish tanks; monitoring the health and safety of fish, including preventive measures to prevent and identify the main diseases of fish.
Fish become ill as a result of violation of the conditions of keeping and feeding, as well as when parasitic organisms enter the pools, therefore, in the fish farm when growing sturgeon fish, a complex of veterinary and fish-breeding measures is strictly carried out to ensure proper sanitary culture and preservation of the fish being raised. The fish is kept in optimal conditions for it, the temperature, the concentration of oxygen dissolved in the water, and pH are controlled. Sturgeon fish are susceptible to a number of diseases of various etiologies: infectious, invasive, alimentary and diseases associated with a violation of the gas regime of water. Infectious diseases are the most dangerous, difficult to diagnose, caused by viruses, bacteria and fungi. Invasive diseases are caused by animal parasites: protozoa, flat and round worms, crustaceans, and others. There are a lot of fish diseases, their accurate diagnosis is quite difficult. For this, methods of microbiology, parasitology, as well as immunology and mycology are used, bacteriological and virological studies are carried out. Therefore, the main task of the fish farmer is to prevent the occurrence of the disease. For this, there are preventive measures that must be strictly observed.
In the sturgeon farm, for preventive purposes, to prevent diseases, pools, equipment and incoming water are disinfected. Malachite, brilliant green and methylene blue are used. These preparations are dissolved directly in water at a rate of 0.5-0.9 mg / l, the exposure and the frequency of treatment are determined depending on the age and type of fish, composition and quality of water. For prophylactic purposes, the farm also uses baths of 2.5% sodium chloride solution with an exposure time of 20 minutes.
The systematic and timely implementation of the complex of fish-breeding and sanitary measures will undoubtedly have a beneficial and positive impact on the cultivation of sturgeon fish.
