Rybohospodars'ka nauka Ukrayiny (Fisheries Science of Ukraine)

5-21

Authors: V. Sondak, O. Volkoshovetz, N. Kolesnik, M. Simon

Purpose. To study ichthyocenosis, species composition and current state of fish populations in small river basins from Pripyatske Polissiya of Ukraine, to propose the ways of their rehabilitation and restoration. Methodology. The study analysed data for last 60 years on the results of monitoring catches of fish wintering grounds of the first-order tributaries of the Pripyat River — right-bank rivers (rivers Slovechna, Sluch, Tina), as well as more than 300 flood plain lakes of the Desna River. Fish were caught by expeditionary methods using boats, seines and gill nets before ice formation in November-December. Methods generally accepted in ichthyology and ecology as well as surveys of anglers were used. Findings. The study showed the crisis state of the Upper Dnipro region, which was confirmed by the data on a significant decrease in fish productivity. The reasons for this are: non-observance of the basin approach in nature management, ineffective nature conservation measures, lack of measures for the rehabilitation of "natural localities" for the reproduction of native ichthyofauna. It should be noted that the creation of National Reserves and NaturalParks (Shatskyi, Pripyat-Stokhid, Rovenskyi, Polesskyi, Menskyi, etc.) did not significantly affect the general state of the problem, and rather has a declarative meaning. Since, although they still have some places with good reproduction conditions for native flora, fauna and valuable natural landscapes, however, this does not affect the general ecological situation in the river network. This is due to the fact that the surface runoff from territories without destructive human impact, which form the hydrochemical regime, is a fraction of a percent of the total amount. Accordingly, the following is observed: shallowing of river channels, smoothing of the bottom, siltation of wintering grounds, decrease in breeding stock number, degradation of spawning grounds and a lack of artificial stocking measures. This leads to a 10-fold decrease in fish catches in small rivers from Pripyatske Polissiya of Ukraine over the past 20 years. Originality. The study examines the problem of the relationship between the accessary river network and the fish productivity of rivers, including the Kуiv (receiving the flow of the DniprоRiver) and the upper reaches of the Kaniv (receiving the flow of the DesnaRiver) reservoirs. It outlines their role in the functioning of the trilateral natural complex located on the territory of Ukraine, Belarus and Poland. The possibility of creating the ichthyo-ecological reserve "Verhniy Dnipro on the territory of Ukraine on the base of existing protected areas within the Pripyat and Desnyansky hydroecological corridors is analysed. Practical Value. It has been proved that the creation of the "Verhniy Dnipro" will allow not only creating a stable base for the natural reproduction of native ichthyofauna in the upper reaches of the Dnipro reservoir cascade but providing high-quality water to the population of Kyiv and the Kyiv region. The concept of rehabilitation of reproduction and conservation of biodiversity of native ichthyofauna in the river network is proposed to maintain the stability of the biosphere, the implementation of which requires little funds.

38-46

Authors: L. Dragan, N. Mikhailenko, T. Bersan

Purpose. To assess the current hydrochemical characteristics of water in the Karpych Lake for determination of the possibilities for fish rearing. Methodology. The paper presents the results of determining the hydrochemical composition of water in the Karpych Lake, village Hvozdiv, Vasylkiv district, Kyiv region. The hydrochemical analysis was performed according to standard methods using the photometric method for determining pollutants in surface waters: concentration of ammonium nitrogen (with Nessler's reagent), nitrites (with Griss reagent), nitrates, phosphates (with ammonium molybdate) and total iron (with orthophenanthroline), the chloride content was determined by argentometric titration. The pH was determined electrometrically, and the content of sulfates and dry residue by gravimetric method. All above mentioned methods are key parameters in a comprehensive assessment of the ecological condition of the lake. Findings. The major ingredients of the hydrochemical composition of water, which characterize its physical properties (hydrogen index, suspended solids, hardness), salt (chlorides, sulfates, calcium, magnesium, sodium, bicarbonates), biogenic nitrogen (ammonium nitrogen, nitrites, nitrates), phosphates, iron were studied and analyzed in laboratory conditions. The results of laboratory measurements of the chemical composition of water samples, as well as the analysis of maximum allowable concentrations of substances for water bodies of fishery importance (MACrg) give grounds for certain conclusions of the current hydrochemical state of water of the studied lake Karpych. Originality For the first time, an assessment of the current hydrochemical characteristics of water in the Karpych Lake was conducted to determine the possibilities of fish rearing. Practical Value. The obtained results are necessary to establish the possibilities of using the Karpych Lake for growing and breeding commercial fish.

59-67

Authors: B. Hankevych, O. Tretiak, O. Kolos

Purpose. Assessing the results of winter keeping of paddlefish young-of-the-year in ponds of the Forest-steppe and Polesye of Ukraine. Methodology. The study was carried out using 0.05-1.0 ha ponds intended for winter keeping of carps. The stocking density of paddlefish young-of-the-year with an average weight of 94.2-147.2 g in wintering ponds was 4.10-16.63 thousand fish/ha. The study of the physicochemical parameters of the aquatic environment was carried out according to the methods generally accepted in hydrochemistry and fish farming. The main piscicultural-biological parameters during the wintering period of fish were assessed using methods commonly used in ichthyology and fish farming according to the level of survival and body weight loss of paddlefish. Findings. The environmental conditions in the ponds during most of the wintering period of fish met the biological requirements of the studied object of cultivation. The water temperature varied within 0.9-6.50C. The dissolved oxygen content in water did not fall below 3.6-3.8 mgO2/dm3 and was mainly at the level of 3.9-7.9 3.9-7.2 mgO2/dm3. Other hydrochemical parameters were within acceptable values ​​for wintering fish in pond conditions. As a result, the survival rate of paddlefish young-of-the-year during the wintering period was 81.5-89.7%. The body weight loss of fish during the winter keeping was on average in the range of 6.41-8.17%. A conclusion was made on the need to conduct additional studies of physiological and biochemical parameters of paddlefish during the wintering period. Originality. New data were obtained on the peculiarities of wintering of paddlefish seeds in ponds of the Forest-steppe and Polesye of Ukraine. Practical value. The study results are part of the database for the development of improved technologies for sturgeon breeding in Ukraine.

78-110

Authors: Yu. Rud, O. Zaloilo, L. Buchatsky, I. Hrytsyniak

Purpose. As the climate change impacts freshwater and marine ecosystems, and rising ocean temperatures and acidification continue to this moment, our aim was to analyze the literature and summarize information on the development of fish infectious diseases in the light of global warming. Findings. Even a slight increase in temperature affects the life cycle, physiology, behavior, distribution and structure of populations of aquatic bioresources, especially fish. Recent studies show that some infectious diseases of fish spread much faster with increasing temperature. Climate change contributes to pathogens spread in both marine and freshwater areas. In particular, rising water temperatures can expand the range of diseases. Aquatic bioresources have high cumulative mortality from infectious diseases, and pathogens are rapidly progressing, and these phenomena may be powered by climate change, leading to the geographical spread of virulent pathogens to fisheries and aquaculture facilities, threatening much of global production and food security. The article presents data on the impact of climate change and global warming on aquaculture and fisheries. The list of the main pathogens of fish of various etiology in Ukraine, including viral, bacterial and parasitic diseases is presented. The impact of infectious agents on modern aquaculture is described and the main ideas about the possible long-term consequences of climate change for fish farms are given. Practical Value. The review may be useful for specialists in veterinary medicine, epizootology and ichthyopathology.