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.
Purpose. The role of aquaculture products in imports of Ukraine given the importance of imports in providing demand of the population on seafood and fish products and prospects are assessed, opportunities for import substitution of the main species of imported fish originating from aquaculture.
Findings. Food security of any country is formed by the balance of its own production, exports and imports. In most European countries, the leading role in satisfaction of demand of the consumers for fish and seafood as of today is played by the import of fish and seafood (HS groups of commodoties 03, 1604, 1605 and 230120), and not their production in the country. Imports play a very important role in saturating the Ukrainian fish and seafood market. Due to the growing role of fish farming (aquaculture) in the world, the role of aquaculture products in Ukrainian imports for the period from 1996 to 2019 includes has been analyzed. The leading role of aquaculture products in the import of fresh and chilled products and relatively small in the subgroup of frozen products is noted. The higher prices of aquaculture products compared to catch fishery products has been confirmed. Assumptions are made about the possible replacement of import of the leading categories of imported products originating from aquaculture and about probably the most advanced technologies of fish farming and species of aquaculture in Ukraine with the current structure and traffic of commodities in global aquaculture and current expenditures of Ukraine on R & D in aquaculture.
Practical value. The data obtained can be useful and used by scientists, practitioners, students, specialists, whose areas of interest include aquaculture and imports, exports of fish products.
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.
Purpose. To determine and analyze the structural and quantitative parameters of secondary commercial species of the Kremenchug reservoir.
Methodology. The data of commercial catches of the Kremenchug reservoir for 2009–2019 were used as primary materials. The methods generally accepted for ichthyological studies were used for the sampling and further analysis
Findings. Commercial catches of native fish species belonging to the category of "secondary large species" (catfish, pike, asp, chub) in the Kremenchug reservoir in recent years show a tendency for an increase: in 2010-2014 their landing was at 78 tons, in 2015 - 104 tons, in 2016 - 107 tons, in 2017 - 134.9 tons. This increase was mainly (by 65%) ensured catfish, to a lesser extent (by 30%) by pike. In 2018, there was a significant decrease in landings in this category to 116.1 tons, in 2019 - again an increase to 140.7 tons.
A similar trend was observed for the category of secondary small-sized species (perch, knife, rudd, tench): in 2010-2014 the catch did not exceed 66 tons, in 2015 - 104 tons, in 2016 - 107 tons, in 2017 - 97 tons. In recent years, the maximum catches of commercial native fish species belonging to this category were observed, e.g., 179.6 tons in 2018, 175.3 tons in 2019.
Due to a low abundance of these species, both commercial and survey catches have a certain instability, while there is a lack of clear trends in the dynamics of structural and functional parameters of catches. The main factor that limits the statistics of this category is the organization of fishing and accounting of landed fish.
Originality. For the first time, data on commercial catches of native fish species belonging to the category of "secondary large species" and "secondary small species" in the Kremenchug reservoir in recent years have been obtained and analyzed.
Practical significance. The obtained results will be used for preparation of the fishing regime in the Kremenchug reservoir. Improving the level of organization of fishing and accounting of landed fish.
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.
Purpose. Determining the growth dynamics of whitefish juveniles in conditions of recirculated aquaculture systems to current needs of industrial aquaculture of Ukraine.
Methodology. The work was performed in accordance with generally accepted guidelines used for coregonid rearing in industrial aquaculture. The study was conducted in a specialized farm for whitefish breeding - "Lavaretus" LLC.
Findings. Weight and linear growth during the period of cultivation in controlled conditions of whitefish young-of-the-year were characterized by dynamics, which were generally close to that typical for coregonids. The study included four coregonid species with different feeding types. Planktivorous (peled), bentivorous (whitefish), polyphagous species that is able to feed on various food organisms (muksun) and peled/broad whitefish hybrid. Feeding regime: during the transition to the mixed feeding was carried out 48 times a day (14 hours with an interval of 15 and 30 minutes) manually; further, according to an increase in fish weight was reduced to 4 times a day using automatic feeders. The average weight and length of young-of-the-year grown in a recirculating aquaculture system was: - peled – 5.6 ± 0.4, muksun – 10.1 ± 0.6.9, Baltic whitefish – 8.6 ± 1.2 g, peled/broad whitefish hybrid – 7.9 ± 0.2 g. The coefficient of variability of weights were: peled – 40.4%, muksun – 32.2%, Baltic whitefish – 21.1%, peled/broad whitefish hybrid – 41.9%.
Originality. New data on piscicultural-biological parameters and dynamics of growth of juveniles of various coregonids or cultivation in conditions of a recirculating aquaculture system were obtained.
Practical value. The development of whitefish farming technology in RAS conditions, which, in contrast to salmon cultivation, is only at the initial stage of implementation, so obtained data will be the basis for the development of whitefish culture in Ukraine.
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.
Purpose. Forming a thematic bibliographic list of publications devoted to studies of leukocytes (white blood cells) of various fish species such as granulocytes, or granular leukocytes (neutrophils, eosinophils, basophils), and agranulocytes or agranular leukocytes (lymphocytes, monocytes).
Methods. The complete and selective methods were applied in the process of the systematic search. The bibliographic core have been formed with the publications exclusively in Ukrainian and Russian from the fund of scientific library of the Institute of Fisheries NAAS of Ukraine.
Results. A thematic list of publications with a total quantity of 78 sources covering a time interval from 1953 to 2017, and including the results of studies of fish leukocyte blood cells, in particular, their functions, patterns of formation, mobilization, utilization, migration, depending on the season, age, physiological condition of fish and other factors has been composed. The literarysources 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 list may be useful for scientists, practitioners, students, whose area of interests covers the questions of hematology, ichthyopathology, immunology, physiology and biochemistry of fish.