The volume of decapod crustacean production in aquaculture has steadily increased in recent years. At the same time, studies focused on the intensification of technological processes have gained special popularity. One of such area of focus is the use of recirculating aquaculture system. In this work an analysis of the main factors inhibiting the process of intensification of the cultivation of decapod crustaceans in the recirculating aquaculture system was carried out as exemplified by Australian crayfish Cherax quadricarinatus. The main factors are cannibalism and the suppression of small crayfishes by large individuals. In the experiments, the influence of group and individual housing, length frequency and tank size on growth and survival rate was studied. All individuals used in the experiment were obtained from one female. The duration of the experiments was six months. A positive correlation of cannibalism with the stocking density was revealed. The formation of one-two dominant individuals suppressing the growth of the remaining individuals of the group was observed in small-sized tanks. In individual housing the grows rate of small crayfishes was higher than that of large ones. Experiments with different-sized juveniles showed that the size separation allows to obtain faster and more evenly growing groups, but it does not solve the problem of cannibalism. Considering the results, it is recommended to provide size classification two times in the first three months and decrease the stocking density. Cannibalism can be excluded only with the individual housing.
Whiteleg shrimp Penaeus vannamei (Boone, 1931) is one of the most popular and promising objects of world aquaculture. In this article possibilities and prospects of cultivating this species in Russia, the results of studies of temperature and salinity effects on the survival rate, growth, activity and food intake of white-footed shrimp were discussed. The critical values of temperature and salinity for this species have been determined. The most progressive for whiteleg shrimp cultivation are the southern regions of Russia, which have an extended sea coastline or a lot of hyperhaline or brackish waterbodies. Technologies combining commercial pond rearing with preliminary rearing of juveniles in RAS are recommended to use to increase the efficiency of cultivation.
The work evaluated the survival and growth of white leg shrimp Penaeus vannamei juveniles in recirculating water systems when feeding with different types of mixed fodders. It is shown that in the early stages of development from 25 to 150 days a fodder with negative buoyancy should be used. A protein content in a fodder between 45 to 57 %% does not affect the growth of the white leg shrimp aged from 85 to 150 days. The study found that in order to enhance the color intensity of commercial products, it is necessary to use fodders with high astaxanthin content. When using high-grade fodder for over the 150 days of cultivation, it is possible to obtain individuals with an average weight of 25 g.
The aim of the work is to investigate the effect of compound feeds with different levels of protein on the growth of juveniles of the Australian red claw crayfish Cherax quadricarinatus. Used methods: To solve this problem, two experiments were carried out in the aquariums of aquaculture invertebrate department at VNIRO: the first was on juveniles weighing 0.017 ± 0.004 g and 0.87 ± 0.08 mm long; the second one was on juveniles weighing 0.31 ± 0.14 g and 23.7 ± 3.9 mm long. The duration of the experiments was 30 and 40 days, respectively. Feeding of juveniles was carried out with three variants of compound feed recipes with an estimated protein content of 25 %, 35 % and 45 %. The main part of the formulations consisted of components of plant origin. Tetra Wafer Mix food for fish and crustaceans (Germany) with a protein content of 45 % was used as a control. The duration of the experiments was 30 and 40 days, respectively. Feeding of juveniles was carried out with three variants of compound feed recipes with an estimated protein content of 25 %, 35 % and 45 %. The main part of the formulations consisted of components of plant origin. Tetra Wafer Mix food for fish and crustaceans (Germany) with a protein content of 45 % was used as a control. Newness: Development of a feed formulation for rearing juveniles of the Australian red claw crayfish in recirculating aquaculture systems (RAS). Results: These experiments showed that the growth rate of juvenile Australian red claw crayfish is directly dependent on the proportion of protein in the feed. It was established that the relative content of protein in the muscles of crayfish depends on its content in compound feed. An analysis of our own and published data indicates that feeds with protein content below 35 % cannot be recommended for growing of juveniles’ Australian red claw crayfish. Feeds with a protein content of 45 % are optimal for the growth of juveniles. It was established that the effectiveness of compound feeds depends not only on the protein content and energy value, but also on their taste attractiveness. Practical significance: The obtained results will be used in the development of mixed feed for juveniles Australian red claw crayfish.
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