Rybohospodars'ka nauka Ukrayiny (Fisheries Science of Ukraine)

7-17

Authors: K. Geina

Purpose. To find qualitative and quantitative parameters of juvenile fish communities as a basis for commercial fish stock and biological diversity in the Dniprо-Bug ria system. Methodology. Primary data were collected during summer-spring period 2006-2015 from catches of small-mesh fishing gears for catching juvenile fish such as beach seine and trawl. In total, catches of 375 stations were analyzed; the total hauled area was more than 50 thousand m2 of littoral shallow waters. To characterize commercial catches, the data of official fishery statistics. Data collection and processing were performed according to generally accepted methods. Findings. The data on species composition, abundance and distribution of juvenile fish communities in the Dnipro-Bug ria system has been selected and analyzed. Major trends in the dynamics of catches of fish juveniles per unit effort as an integral feature of natural reproduction and basis for the recruitment of commercial fish stocks have been detected. Reproduction conditions of various ecological groups of fishes have been studied. The dynamics of the qualitative composition of commercial catches has been analyzed. Last years, the majority of commercial catches in the Dnipro-Bug ria system consists of Black-sea sprat (62.2%) and Prussian carp (21.4%); the category of “valuable commercial species” composed 7.3% of the total catch. Self-reproductive fish populations ensured formation of 93.5% of the total catch. i.e. natural reproduction remains the major source of the recruitment of commercial fish stocks in the Dnipro-Bug ria system. According to the data of studies of 2006-2015, juveniles of 18 fish species were recorded in the littoral zone, the majority of which (56.3-57.2%) were low value and secondary species – Prussian carp, Black-sea sprat, atherina. Among valuable commercial species, the most abundant were roach (7.3%) and bream (3.4%); at the same time, these species formed 16.4% of the total catch in gill nets in 2010-2017. The inter-annual dynamics of the abundance of juveniles of commercial fish species during last 10 years has been characterized by positive trends that under condition of the maintenance of optimum hydrological regime of the Dnipro-Bug ria system indicates in the possibility of ensuring stable commercial catches in the nearest future. Originality. The data on the structure of juvenile fish communities of the lower reaches of the Dnipro river as a component of fish fauna of the Dnipro-Bug ria system have been provided. A detailed description of the dynamics of the number of juveniles of major commercial fish species in an inter-annual aspect has been provided. Practical value. The obtained results have been used for the development of long-term prognoses of fish productivity parameters as a basis for the regulation of qualitative and quantitative parameters of commercial fishing pressure and conservation measures.

48-59

Authors: M. Pashko, O. Tretiak, O. Kolos

Purpose. To study environmental conditions and individual fish culture parameters in the process of rearing brood sterlet herders in cages at natural temperature regime of water bodies of the forest-steppe zone of Ukraine. Methodology. The material for the study were age-1–7 groups of sterlet reared in floating cages with areas of 24 m2. Fish were fed by specialized feeds with the content of crude protein of 45–64% and raw fat of ― 12–15%. The individual and mean body weight (g), relative weight gain (%) and fish survival rate (%) were studied; fish production per unit area of cages (kg/m2) and feed costs per unit weight gain (kg/kg) were calculated). The determination of the physical and chemical parameters of the environment was carried out using generally accepted methods in fish culture and hydrochemistry. Findings. The mean monthly water temperature was in the range of 21.7–26.3°C in the summer. The period with a water temperature of 18–25°C was 75-80 days. The mean daily content of dissolved oxygen varied within the range of 2.4–11.6 mgO2/dm3. The mean monthly oxygen concentration in summer was between 3.7 and 6.2 mgO2/dm3. During the period of fish rearing, minor excesses of normative values ​​have been recorded for some hydrochemical parameters. No mass manifestations of fish diseases were detected. It was established that feed costs per unit of body weight gain (kg) increased with fish age, on average, from 1.29 to 1.98 kg. Fish production in cages was 5.33–11.35 kg/m2. On the seventh year of life, the brood sterlet reached a mean weight of 1796.80 ± 73.33 g (Cv = 20.4%). Survival rates for sterlet of different age groups were 78.50–98.96%. The number of sterlet for the organization of caviar and meat production was calculated. Originality. Peculiarities of rearing different age groups of sterlet with the use of the methods of industrial aquaculture uncommon in Ukraine under conditions of cage aquaculture systems installed in water bodies with natural temperature regime have been investigated. Practical value. The results of the study are of interest for the development of modern methods of aquaculture of sturgeons in the conditions of farms of industrial type.

68-85

Authors: R. Palamarchuk, O. Deren, N. Mikhailenko, M. Korylak

Purpose. To determine the efficiency of using amaranth (Amaranthus) in carp feeding under standard rearing conditions and under the effect of stress-factors common in aquaculture, in order to activate the antioxidant protection system of their organism. Methodology. Fishery and hydrochemical studies were conducted according to generally accepted methods. The protein content was determined by the Bretford method. The concentration of diene conjugates was studied using a method based on the reaction of the optical density of a heptane isopropanol lipid extract. Determination of the concentration of TBA-active products was carried out spectrophotometrically by a color reaction with thiobarbituric acid. The activity of superoxide dismutase (SOD) was determined as the percent of the inhibition of nitrosin tetrazolium reduction reaction in the presence of phenazine methosulfate. Catalase activity was determined by changing H2O2 concentration. Findings. The research was conducted in the aquaria room of the Institute of Fisheries NAAS. The effect on the antioxidant protection system activity of the organism of carp yearlings after addition of amaranth to their diet in the amount of 10% has been analyzed. Rearing was carried out under standard conditions and under the effect of stress-factors that are common for fish culture: pollution of the aquatic environment caused by the introduction of intensification measures; complex contamination of water with simultaneous decrease in the dissolved oxygen content. The research showed that the additional feeding of amaranth to carps under standard conditions of cultivation, there was a certain tendency to an increase in the content of SOD in muscle and hepatopancreas (by 5.9–8.3%) and to an increase in the content of lipid peroxidation products (by 14.3–15.7%). The effect of stress factors showed more marked tendencies. Thus, in polluted water, the activity of SOD in muscle significantly increased (p˂0.01), at the same time, the content of diene conjugates (p˂0.01) increased. In hepatopancreas, a tendency to a 2.9% increase in the activity of catalase and a 44.1% decrease in the content of diene conjugates was observed. Under the complex effect of stress factors, the activity of catalase and TBA-products in muscles tended to decrease, diene conjugates tended to increase, while SOD increased (p˂0,01). In hepatopancreas, there was a tendency to an increase in the content of catalase and SOD, respectively, by 16.5% and 5.9%. At the same time, the content of products of lipid peroxidation — TBA products (p˂0,01) and diene conjugates (p˂0,001) reduced. Originality. The analysis of anti-oxidant properties of amaranth and the degree of the effect of feeding this additive to carp yearlings on the antioxidant protection system activity of their organism under standard conditions of cultivation and the effect of stress-factors common for aquaculture have been analyzed. Practical value. Supplementation of carp diet with amaranth in production conditions can be used as a way to reduce the degree of adverse effects of common environmental stress-factors (contamination as a result of intensive measures and decrease in dissolved oxygen content in water to critical values) on the functional state of fish organism by increasing the antioxidant protection system activity.

99-121

Authors: M. Simon

Purpose. Forming a thematic bibliographic list of English-language publications on certain issues of vital activity of sturgeon (Acipenseridae), both in natural conditions and in aquaculture. Particular attention was given to species that are not common in aquaculture of Ukraine. Methods. The complete and selective methods were applied in the process of the systematic search. The bibliographic core was made up of literary sources from electronic archives of world-renowned specialized scientific journals. In particular: Journal of Applied Ichthyology, Environmental Biology of Fishes,Conservation Biology, Lake and Reservoir Management, Estuaries,Freshwater Fisheries, Aquaculture, North American Journal of Fisheries Management, Canadian Journal of Fisheries and Aquatic Sciences, Copeia & others. Results. A thematic list of main publications including thematic scientific collections, materials of international scientific and practical conferences, scientific articles and abstracts of dissertations was composed. It consists of 187 English-language papers. Presented publications cover the time interval for the last thirty years. The literary sources are arranged in alphabetical order by author or title, and described according to DSTU 8302:2015 “Information and documentation. Bibliographic reference. General principles and rules of composition”, with the amendments (code UKND 01.140.40), as well as in accordance with the requirements of APA style ‒ international standard of references. Practical value. The prepared list may be useful for scientists, practitioners, students, whose sphere of interests is related to issues of questions breeding sturgeon in aquaculture and conservation of populations of rare species of fish.