Rybohospodars'ka nauka Ukrayiny (Fisheries Science of Ukraine)

16-25

Authors: O. Fedonenko, N. Esipova, O. Marenkov, T. Sharamok

Purpose. To analyse the current state of fisheries in Dnipropetrovs’k region and elaborate a strategy of their development for the period of 2015–2019. Methodology. We used the summarized results of hydrobiological, ichthyological and toxicological studies carried out during 2010–2014. Data were collected in the Zaporizhzhia reservoir and small water bodies with standard sampling gears. A set of control gears (gill nets with mesh size of 30–120 mm) was used to investigate the fish fauna. Juvenile fish were caught in the third decade of July – first decade of August with 10 m beach seine. Findings. The analysis of fisheries in Dnipropetrovs’k region for the past five years showed that the disorder and absence of scientifically-based approach to fisheries processes as well as the low level of professional training of aquatic resource users resulted in low fish productivity in the majority of reservoirs, which ranged within 25–30 kg/ha that was several times less than the real potential fish productivity. The proposed Conception of fisheries development provides a set of coordinated measures aimed at ensuring sustainable use, effective protection and restoration of aquatic biological resources, fisheries management based on natural, economic and environmental conditions of different types of water bodies. The developed practical measures allow increasing the amounts of fish product supply to the internal consumer market by at least 5 times without any environmental damage, expanding its assortment and reducing the costs by 25–30%. Originality. For the first time, the Conceptual approaches to the regional management of aquatic biological resources in the conditions of specific human impact were introduced. They are aimed at implementing the scientific rationale of the measures for their rational use, artificial restoration, reclamation, etc. Practical value. The proposed Conception is to provide the food requirements of the population of Dnipropetrovs’k region in fish products of domestic origin at scientifically based consumption norms. Keywords: fisheries, Zaporozhzhia reservoir, water bodies of Dnipropetrovs’k region, hydroecological condition, fish productivity, artificial reproduction.

34-44

Authors: K. Geina, P. Kutishchev

Purpose. To analyze major biological characteristics of pike (Esox lucius L., 1758) stock in the lower Dnieper River in the conditions of transformed flow. Methodology. Collection of the ichthyological material was carried out in the lower Dnieper River from commercial fishing gears, including beach seines, drag seines, fyke-nets. Field, laboratory processing of samples and mathematical analysis of the obtained results were carried out according to generally accepted methods and guidelines with some assumptions regarding the duration of pike fattening directly in the lower Dnieper River. Findings. Recent years, there is an increase in the specific weight of younger age groups in the pike stock in the lower Dnieper River. Analysis of linear growth indicates on satisfactory environmental conditions for pike. Current commercial contingent of pike is based on size classes of 46–50 cm versus 22–32 cm in the first half of the last century. Reproductive properties of pike, in particular fecundity, egg size and maturity coefficients did not virtually change compared to those of the last century. Depending on linear sizes, the absolute fecundity is 32.3–155.8 thousand eggs and the maturation coefficient is 11.1–15.7%. Morphologic variability of pike in the lower Dnieper River during the period from 1980s to the present time was observed for plastic features, which characterized fin sizes. Sexual dimorphism in current conditions was observed only for maximum body depth. No significant differences for other plastic features between males and females of pike in the lower Dnieper River. Originality. The data on biological characteristics of pike stock from the lower Dnieper River have been updated. Current fecundity of females of different size groups recorded in commercial catches was been determined. An analysis of morphological variability of major plastic features of pike in the process of the transformation of the Dnieper River flow has been carried out. Practical value. The determined peculiarities of pike linear growth will allow optimizing commercial harvest for preserving the most productive part of the stock. Such measures will contribute to an increase in the commercial stock of this valuable predatory fish of the Dnieper-Bug mouth system that in turn will ensure appropriate regulation of the number of coarse non-commercial fish. This is highly important for the balanced trophic strain for valuable commercial species at early stages of their development. Key words: lower Dnieper River, Dnieper-Bug mouth system, predatory fish, pike, linear growth, size classes, fecundity, morphologic variability.

56-70

Authors: O. Bedunkova

Purpose. To assess the developmental stability and cytogenetic homeostasis of fish populations in the Sluch River in the watercourse areas subjected to anthropogenic stress of different intensities. Methodology. Studies of fish populations in the Sluch River were carried out within Berezne district of Rivne region. The condition of individual fish in the populations were evaluated integrally using morphological (evaluation of the stability of development based on the level of fluctuating asymmetry (FA)) and cytogenetic (micronucleus (MN) test of peripheral blood erythrocytes of fish) methods. The methods used allowed identifying the destabilization level of organism development, even in the cases when there is no direct disturbance of population homeostasis. Findings. The found FA levels reflect minor (initial) deviations from the normal developmental processes of fish populations in in the studied watercourse areas. Especially significantly this is reflected in a high proportion of individuals with FA in the samples of roach, bleak, bream and perch. An excess in the frequency of MN erythrocyte cells in roach and pike blood relatively the level of spontaneous mutagenesis was observed in the cross section #2, which is exposed to sewage waters. The observed manifestation of degenerative processes in fish organisms at this stage can be evaluated as an increased reactivity of sensitive species to the presence of mutagenic agents in the composition of river pollution. The functioning of spawning populations gives reason to believe that the current level of human impact is not critical for the hydroecosystem. Originality. For the first time we obtained data on the stability of development and cytogenetic homeostasis of fish populations in the hydroecosystem of Rivne region in current conditions of anthropogenic stress. Practical value. The obtained results can be used for assessment and prognoses of wild fish stocks of the investigated hydroecosystem and can be taken into account when planning water protection activities within the river basin. Keywords: fish populations, fluctuating asymmetry, cytogenetic homeostasis, developmental stability.

81-87

Authors: N. Tson

Purpose. To study fish culture parameters of young-of-the-year carp in the conditions of industrial fish-growing ponds when applying experimental repeated fertilization with distiller’s grain. Methodology. The study was conducted in industrial fish-growing ponds. The wastes of alcohol industry – the distiller’s grain as organic fertilizer was gradually introduced into ponds at following amounts: first application – 1,0 t/ha, second application in 10 days – 0,5 t/ha, third application in 12 days – 0,5 t/ha. The control ponds were fertilized with humus (2 t/ha). Young-of-the-year carp were grown in monoculture at stocking density of 30 000 fish/ha. In addition, 100 kg/ha of lime were applied during the culture season in the experiment and control. Fertilization with humus and application of lime in ponds, hydrochemical studies, sampling and processing of hydrobiological samples, fish culturing and statistical studies were carried out according to standard methods. Findings. Gradual fertilizing with distiller’s grain (to the total 2 t/ha) gave the possibility to create favorable hydrochemical and hydrobiological regimes. An average daily growth in the experimental fish groups of 0,44 ± 0,09 g/day that was similar to in the control (0,45 ± 0,11 g/day) with positive significant correlation between them (r = 0,97; p <0,001) was achieved. The performed measures gave a possibility to obtain fish productivity in the experimental variant 10.7% more than in the control. An economic effect of 14.3% cost reduction for fertilizing ponds was achieved. Originality. For the first time we presented the results of fish culture and biological parameters of young-of-the-year carp in industrial ponds when applying 3-time fertilization with distiller’s grain. Practical Value. The obtained results are the basis for the broad use of non-traditional organic fertilizer – distiller’s grain in industrial ponds, when growing young-of-the-year carp in monoculture. Keywords: carp, young-of-the-years, distiller’s grain, natural food base, fish-growing ponds, fish productivity.

96-107

Authors: А. Vodyanitskyi, А. Potrokhov, О. Zinkovskyi

Purpose. To determine the effect of temperature regime fluctuations on the development of silver carp embryos, as well as the activity of enzymatic reactions in fish eggs. Methodology. The studies were conducted at the experimental station of the Institute of Hydrobiology of Bila Tserkov, Ukrainian National Academy of Sciences, from June to July. The biological materials were silver carp eggs, embryos and larvae. The dissolved oxygen content was determined using the Winkler method at four o’clock in the morning. Alkalinity phosphatase and LDG activity were determined using a set of reagents «Alkalinity phosphatase» and «LDG» (Phyllis diagnosis, Ukraine). SDH activity was determined by Vexy. The activity of Na, K-Mg-dependent-activated ATPase was determined as growth of inorganic phosphorus in the incubation medium by Kindratova M.N. et al. Protease activity was determined using immune enzymatic method of Tyurina et al. The obtained results were processed statistically in Statistica 5.5, Epaprobit analysis was used for calculating LC/EC values (Version 1.5). Findings The results showed that a delay of embryonic stages of development occur, the number of abnormal embryos increases, and the reproduction efficiency of fish reduces with an increase in water temperature and decrease in the dissolved oxygen content in water. The temperature factor had a significant effect on the activity of key enzymes, in particular the energetic metabolism changed from aerobic to anaerobic. Originality. It was found a negative effect of abiotic factors of water medium and drastic fluctuations in water temperature and gas regime of water bodies on the course of embryogenesis of silver carp that is especially important in the conditions of climate change. Practical value. The obtained results showed that the level of optimum and unfavorable environmental factors during the change of embryonic stages in embryonic and larval fish can be established based on the activity of lactate dehydrogenase, succinate dehydrogenase, ATPase and protease. Keywords: embryonic development, silver carp, fluctuations of temperature regime in water bodies, enzymatic activity.