Search

Over the entire period of studies in the water bodies in the Ural River basin, comprehensive hydrobiological studies have not been carried out in many areas both on the main watercourses of the Ural and Sakmara rivers and on a large number of tributaries of different levels. The results of such studies carried out by the Water Problems Institute, Russian Academy of Sciences, during expeditions in the summer and autumn 2022 are discussed. A large body of data on phytoplankton, zooplankton, zoobenthos, and juvenile fish was collected and processed. [ABSTRACT FROM AUTHOR]

Purpose. Analysis of obtained data and integration of previous hydroecological data and statistical information for the preparation of scientific and biological rationale and development of the regime for rational and environmentally sustainable fishery exploitation of the Khrystoforivske Reservoir. Methodology. Hydrochemical and hydrobiological methods of sampling, laboratory and statistical processing of the material were used in the water area of the Khrystoforivske reservoir of the Bokovenka river during comprehensive studies in the summer of 2022. We studied the hydrochemical parameters of the water body, species composition, quantitative parameters of the main groups of hydrobionts, including fish forage organisms (macrophytes, phytoplankton, zooplankton, zoobenthos), the biological productivity of the reservoir was measured based on the main groups of hydrobionts. To determine the state of the main groups of hydrobionts, two samples of phytoplankton, zooplankton and zoobenthos were collected. Macrophytes were studied, water samples were taken from different parts of the water body for hydrochemical analysis. The biomass of phytoplankton was calculated based on the biomass of standard volumes of algae, the biomass of zooplankton – by multiplying the quantity of organisms by their individual weights, zoobenthos – by weighing individual groups of hydrobionts on torsion scale and recalculating and summing up. The reservoir feeding capacity was assessed by the quantitative development of zooplankton according to known classifications. Findings. The main parameters of the chemical composition and properties of the water of the Khrystoforivske reservoir, which condition the bioproductivity and fish farming performance, were determined: pH, content of dissolved gases, organic substances, biochemical demand of O2, nutrients content, as well as general mineralization and hardness, concentration of the major ions. According to the hydrochemical classification, water is bicarbonate type II and is referred to fresh water. The degree of water saturation with easily-oxidizable organic matter has decreased over the past 15 years and is within standards for aquaculture. Considering all environmental and sanitary parameters, water of the Khrystoforivske reservoir is characterized by fair or average quality, it is eupolytrophic. The water characteristics indicate that the fishery exploitation at the reservoir during previous Special Commodity Fish Farming Regimes (SCFF) (1996–2021) has produced no adverse effects on the general ecological and sanitary condition of water. Aquatic phytocoenoses of the Khrystoforivske reservoir are represented by associations of submerged and aerial-aquatic plants, with a total area of 5.2 hectares. The total production of aquatic plants is 36.245 tons. The phytoplankton of the reservoir includes 51 species of algae (six groups). In terms of quantity, small-celled Cyanoprokaryota predominated (about 70%). Diatoms, green and euglenic algae dominated in biomass. In 2022, the average biomass of phytoplankton in the Khrystoforivske reservoir was up to 1.80 g/m3, the total annual production of phytoplankton reached 201.06 tons. In total, 16 species of organisms have been identified in the zooplankton of the reservoir: Rotatoria, Cladocera and Copepoda. The average abundance of zooplankton in the reservoir was 31,390 ind./m3, and its average biomass reached 0.41 g/m3. The value of primary production of zooplankton is 123.9 kg/ha, and the total stock in the reservoir is 7.687 tons. The fish food supply in terms of zooplankters in the Khrystoforivske reservoir are low. The reservoir itself, based on the group of zooplankton, can be referred to fishery class III (the lowest class). The bottom fauna is represented by 40 taxonomic groups of invertebrates. The Chironomidae and Oligochaeta assemblies are most developed in terms of density, but molluscs dominate in biomass. There is a general trend towards a decrease in the quantitative parameters of macrozoobenthos, in particular, Mysidacea. The average biomass of soft benthos (2.17 g/m2) and the average biomass of the entire zoobenthos (33.62 g/m2) indicate that the reservoir preserves its fishery potential due to macrozoobenthos. The primary production of zoobenthos of the Khrystoforivske reservoir is 130.2 kg/ha. The total stock of zoobenthos is up to 8.072 tons. The values of the fish food supply are quite high due to zoobenthos in the reservoir, the water body in terms of benthos biomass is referred to fishery class II (medium productive reservoirs). The obtained comprehensive data on the food supply of the Khrystoforivske reservoir indicate the availability of sufficient bioproduction potential for its continuous effective fish-farming on the basis of the special commodity fish farming regime. Originality. For the first time in the last 10 years, comprehensive data on the food supply of the Khrystoforivka reservoir, which is used in special commodity fish farming regime (SCFF), have been obtained and analysed. Practical value. The results obtained are of practical importance for the development of scientific and biological rationale for fish farming in the Khrystoforivske Reservoir.

Purpose. Analysis of obtained data and integration of previous hydroecological data and statistical information for the preparation of scientific and biological rationale and development of the regime for rational and environmentally sustainable fishery exploitation of the Khrystoforivske Reservoir. Methodology. Hydrochemical and hydrobiological methods of sampling, laboratory and statistical processing of the material were used in the water area of the Khrystoforivske reservoir of the Bokovenka river during comprehensive studies in the summer of 2022. We studied the hydrochemical parameters of the water body, species composition, quantitative parameters of the main groups of hydrobionts, including fish forage organisms (macrophytes, phytoplankton, zooplankton, zoobenthos), the biological productivity of the reservoir was measured based on the main groups of hydrobionts. To determine the state of the main groups of hydrobionts, two samples of phytoplankton, zooplankton and zoobenthos were collected. Macrophytes were studied, water samples were taken from different parts of the water body for hydrochemical analysis. The biomass of phytoplankton was calculated based on the biomass of standard volumes of algae, the biomass of zooplankton - by multiplying the quantity of organisms by their individual weights, zoobenthos - by weighing individual groups of hydrobionts on torsion scale and recalculating and summing up. The reservoir feeding capacity was assessed by the quantitative development of zooplankton according to known classifications. Findings. The main parameters of the chemical composition and properties of the water of the Khrystoforivske reservoir, which condition the bioproductivity and fish farming performance, were determined: pH, content of dissolved gases, organic substances, biochemical demand of O2, nutrients content, as well as general mineralization and hardness, concentration of the major ions. According to the hydrochemical classification, water is bicarbonate type II and is referred to fresh water. The degree of water saturation with easily-oxidizable organic matter has decreased over the past 15 years and is within standards for aquaculture. Considering all environmental and sanitary parameters, water of the Khrystoforivske reservoir is characterized by fair or average quality, it is eupolytrophic. The water characteristics indicate that the fishery exploitation at the reservoir during previous Special Commodity Fish Farming Regimes (SCFF) (1996-2021) has produced no adverse effects on the general ecological and sanitary condition of water. Aquatic phytocoenoses of the Khrystoforivske reservoir are represented by associations of submerged and aerial-aquatic plants, with a total area of 5.2 hectares. The total production of aquatic plants is 36.245 tons. The phytoplankton of the reservoir includes 51 species of algae (six groups). In terms of quantity, small-celled Cyanoprokaryota predominated (about 70%). Diatoms, green and euglenic algae dominated in biomass. In 2022, the average biomass of phytoplankton in the Khrystoforivske reservoir was up to 1.80 g/m³, the total annual production of phytoplankton reached 201.06 tons. In total, 16 species of organisms have been identified in the zooplankton of the reservoir: Rotatoria, Cladocera and Copepoda. The average abundance of zooplankton in the reservoir was 31,390 ind./m³, and its average biomass reached 0.41 g/m³. The value of primary production of zooplankton is 123.9 kg/ha, and the total stock in the reservoir is 7.687 tons. The fish food supply in terms of zooplankters in the Khrystoforivske reservoir are low. The reservoir itself, based on the group of zooplankton, can be referred to fishery class III (the lowest class). The bottom fauna is represented by 40 taxonomic groups of invertebrates. The Chironomidae and Oligochaeta assemblies are most developed in terms of density, but molluscs dominate in biomass. There is a general trend towards a decrease in the quantitative parameters of macrozoobenthos, in particular, Mysidacea. The average biomass of soft benthos (2.17 g/m²) and the average biomass of the entire zoobenthos (33.62 g/m²) indicate that the reservoir preserves its fishery potential due to macrozoobenthos. The primary production of zoobenthos of the Khrystoforivske reservoir is 130.2 kg/ha. The total stock of zoobenthos is up to 8.072 tons. The values of the fish food supply are quite high due to zoobenthos in the reservoir, the water body in terms of benthos biomass is referred to fishery class II (medium productive reservoirs). The obtained comprehensive data on the food supply of the Khrystoforivske reservoir indicate the availability of sufficient bioproduction potential for its continuous effective fish-farming on the basis of the special commodity fish farming regime. Originality. For the first time in the last 10 years, comprehensive data on the food supply of the Khrystoforivka reservoir, which is used in special commodity fish farming regime (SCFF), have been obtained and analysed. Practical value. The results obtained are of practical importance for the development of scientific and biological rationale for fish farming in the Khrystoforivske Reservoir. [ABSTRACT FROM AUTHOR]

This article examines the conditions for the formation of the hydroecological regime of the Ivankov Reservoir according to data from complex hydrological, hydrochemical, and hydrobiological surveys carried out in August 2020−2022. The differences in hydroecological characteristics are associated with the peculiarities of weather conditions in the summer seasons. Despite the significant flow of the reservoir, in its bottom layer during prolonged hot weather, the formation of oxygen-free conditions is possible, affecting exchange processes with the bottom, hydrobionts, and methane emissions. The increased bioturbation of bottom sediments (BSs) by benthos under oxygen deficiency activates metabolic processes at the water–BSs boundary, including the release of methane. A strong "bloom" of the reservoir, characteristic of hot weather conditions in 2022, led to a reduction in the specific flux of methane from the surface due to its oxidation with an excess of oxygen in the surface layer. [ABSTRACT FROM AUTHOR]

The results of a complex hydrochemical and hydrobiological study of salt lakes in southeastern Transbaikalia during the period of moisture change are presented. The studied lakes, according to geochemical classification, are chloride and soda types. The taxonomic diversity of aquatic biota decreases, while the salinity increases and the hydrochemical type of lakes changes from soda oligo-mesohaline (4–16 g/L) to chloride eu-hyperhaline (33–70 g/L) and soda hyperhaline (128–231 g/L). In soda oligo-mesohaline and chloride lakes, the phytoplankton taxonomic composition is similar and is represented by green and diatom algae, as well as cyanobacteria. Submerged aquatic plants are represented by Stuckenia pectinata in soda oligo-mesohaline lakes. Ruppia maritima is found in the Dabasa-Nor chloride lake. In zooplankton and zoobenthos, rotifers and chironomids dominate respectively. Quantitative characteristics of phytoplankton in oligo-mesohaline lakes are lower than in hyperhaline soda and eu-hyperhaline chloride lakes. The phytomass of submerged aquatic plants, on the contrary, is higher in oligo-mesohaline lakes. In the hyperhaline soda lake Borzinskoye, zoobenthos and zooplankton organisms are represented by planktonobenthos species, namely Anostraca, with low abundance. [ABSTRACT FROM AUTHOR]

Background. The article considers a special type of reservoirs – partially regulated sections of riverbeds and streams formed by hydraulic structures and other artificial obstacles on the example of the Nadezhdinskiy reservoir on the Truev river in Penza region. The purpose of this work is to assess the fish productivity of a pond-type riverbed water-lifting reservoir based on a forage base, ichthyofauna in comparison with the natural riverbed and to determine methods of its fisheries use. Materials and methods. Fisheries research at the Nadezhda reservoir and the Truev river was carried out in August 2017. The selection and processing of hydrobiological and ichthyological samples was carried out according to generally accepted methods used by us in the last decade in small watercourses and reservoirs of the Volga region. Results. The regulated section of the Truev river, referred to as the Nadezhda reservoir, is 8–53 times higher in terms of phytoplankton, zooplankton and zoobenthos biomass than the natural riverbed. Also, the ichthyomass in the reservoir is 4.7 times higher than in the river, in which there were no commercial fish species in the studied area. Fish productivity for the most demanded components of the feed base by local fish species in the Nadezhdinskiy reservoir amounted to 166 kg/ha, in the natural channel of the Truev river – 11 kg/ha. The potential fish productivity may be 115 kg/ha and 13.2 kg/ha, respectively. In general, the total fish productivity differs by 12 times. Due to such high productivity, the Nadezhdinskiy reservoir can be used for sports and amateur fishing, pasture or commercial fish farming. Conclusions. The pond-type water-lifting reservoir is characterized by fish productivity at the level of average indicators of fish ponds and reservoirs of complex purpose in Penza region and the Republic of Mordovia. Channel water-lifting reservoirs should be taken into account in the fund of pond fishing in the region and actively exploited, which will significantly increase the volume of aquatic biological resources in low-water regions.

The paper deals with monitoring results of phytoplankton, zooplankton and zoobenthos of the Sheksna reservoir, lakes Kubenskoye and Vozhe in Vologda Oblast in 2018–2022. The highest biomass of algae was recorded in lake Beloye (10.1 g/m3 ). In other water bodies, the average biomass made up 6.3–7.3 g/m3 . Diatom and cyanobacteria dominated in phytoplankton: diatom number was maximum in the river part of the Sheksna Reservoir, while cyanobacteria – in lake Beloye. Highly abundant Aphanizomenon flos-aquae induced annual water bloom of lake Beloye. Density of zooplankton was the greatest in Vozhe (131 thous. ind./m3 , 3.5 g/m3 ). Similar average biomass of zooplankton was noted in different parts of the Sheksna Reservoir (2.0 g/m3 ). In lake Kubenskoye, biomass reached 0.9 g/m3 . Copepoda formed the base of zooplankton number and cladocera – of biomass. In contrast to lake Vozhe (2.6 g/m2 ), zoobenthos in lake Kubenskoye was highly abundant (7.6 g/m2 ). The average biomass of zoobenthos in the Sheksna Reservoir accounted for 4–5 g/m2 . The dominant complex of zoobenthos included oligochaeta Limnodrilus hoffmeisteri, Tubifex newaensis, T. tubifex in all water bodies; chironomid larvae Chironomus sp., Procladius sp. – in the open sites; chironomids Endochironomus albipennis, Glyptotendipes gripekoveni, Cricotopus gr. sylvestris – in thickets. Chironomidae dominated in the Sheksna Reservoir and lake Vozhe, oligochaeta – in lake Kubenskoye.

This article presents the results of a comprehensive hydrochemical and hydrobiological study of 13 different types of lakes in Transbaikalia conducted in July 2022. Based on factor analysis of hydrochemical and hydrobiological indicators, the lakes were divided into three groups: 1) brackish soda; 2) chloride and sulfate, as well as one salty soda lake, Shvartsivskoe; and 3) brine soda. It has been established that the number of species of different groups of aquatic organisms decreases as the salinity level increases, regardless of the chemical type of water. It has been shown that the dominant composition of primary producers in lakes of different types differs. Two new species of macroalgae for Transbaikalia have been identified (Stigeoclonium flagelliferum Kütz. and Rhizoclonium riparium: (Roth.) Harv.). In the flora of aquatic plants of Baikal Siberia, after more than a 100-year hiatus, Ruppia maritima L is present. The zooplankton of lakes is dominated by halotolerant species. The dominant structure of zoobenthos in brine and salt lakes is dominated by Artemia crustaceans and Ephydridae flies. In deeper brackish lakes, Chironomidae mosquitoes are always the dominant species. Quantitative indicators of phytoplankton and zooplankton communities are characterized by an inverse relationship. With the massive development of cryptophyte algae in brine reservoirs, the abundance and biomass of zooplankton are minimal. No significant fluctuations in the biomass of zoobenthos and phytomass of aquatic plants were detected. In sulfate and chloride lakes, the trophic structure of heterotrophs is represented in zooplankton by a grazing chain, and in zoobenthos by detritivores. [ABSTRACT FROM AUTHOR]

Environmental engineering survey performed at the construction site of the Amur Gas Chemical Complex in 2018 in order to assess the state of aquatic communities of the Zeya River revealed 37 taxa of planktonic algae (below genus rank), 32 species of zooplankton, and 37 species of benthic organisms. In May, phytoplankton was mainly represented by diatoms; in July, it was more diverse, when green algae, golden algae and cyanobacteria all played a significant role. In May, zooplankton included mainly rotifers; in July, crustaceans dominated by biomass at most stations. Zoobenthos was represented in May mainly by oligochaetes and bivalves, while insects dominated in July. The abundance and biomass of phytoplankton, zooplankton, and benthos were low. The Goodnight–Whitley, Parele, Woodiwiss, and Mayer indices testified to relatively favorable environmental conditions in the studied sections of the Zeya River. According to the indicators of phyto- and zooplankton, and zoobenthos, the waters of the river are classified as oligosaprobic.

Lake vegetation is divided into 3 ecological groups: hygrophytes, hydrophytes and hydratophytes. Hygrophytes make up 27.2%, hydrophytes-9.0% and hydrophytes-63.6%. Hygrophytes are plants that grow in moist places, on the shores, and hydrophytes are half aquatic. This plant species is found in small numbers in the lake. Hydrotophytes are dominant in abundance and biomass. The area of the lake is 7,200 hectares, of which the water part is 3,800 hectares, the area of wetlands covered by various parts is 3,400 hectares. The lake is rich in organic nutrients. A wide variety of higher algae grows in the lake (Phragmites communis, typha angustifolia, Potamogeton crispus, Myriophyllum spicatum, Ceratophyllum demersum, Chara infarmedia, Spirogyra, as well as many species of algae), which prevents sunlight from penetrating into the water to a depth of 3 meters, which negatively affects the development of zooplankton.

The paper presents for the first time the results of a comprehensive cadaster study of the right-bank tributaries of the Mezen River (Kyma and Sula rivers) in autumn 2021. The characteristics of the habitat state for aquatic biota and the results of the study of plankton and zoobenthic communities are presented. According to the chemical composition, the waters of the surveyed rivers belong to the hydrocarbonate class of low mineralization and the neutral type according to the pH value. Our results indicate the absence of a noticeable anthropogenic impact on the studied watercourses. The phytoplankton community is characterized by high taxonomic diversity, while the zooplankton and zoobenthic communities, by low taxonomic diversity. Different dynamics of phytoplankton, zooplankton, and zoobenthos in terms of abundance, biomass, and taxonomic composition has been found. According to the fishery standards, the parameters of zooplankton in the Mezen River tributaries allows us to classify them as poor in terms of fodder base for planktivorous fish. According to the zoobenthos parameters, the Kyma River may be characterized as exceeding the average level in terms of fodder base for benthophagous fish, the Sula River, close to the average level. The data on the taxonomic composition and quantitative indicators of the development of hydrobionts in the right-bank tributaries of the Mezen River are the starting point for environmental monitoring of the state of these water bodies. [ABSTRACT FROM AUTHOR]

Purpose. To analyze the range of special scientific literature and summarize the information obtained on the modern biotic features of the Kуiv reservoir. Namely: the state and specificity of communities of phytoplankton, zooplankton, zoobenthos and macrophytes from this reservoir. To consider the main data on their formation, as well as the direction of further development and impact on fish productivity. Findings. An overview of scientific publications devoted to the biotic features of the Kуiv reservoir, which directly affect its potential as a fishery water body, were presented. The literature data on the most widespread communities of phytoplankton, zooplankton, zoobenthos, and macrophytes in this reservoir are generalized. The main directions in which they affect the possibility of commercial fisheries in this reservoir are described. The general aspects of the anthropogenic pressure impact on them, as well as their consequences, are considered. The perspective ways of further development of the Kyiv reservoir as a fishery water body with the systematic implementation of complex reclamation measures and the organization of rational commercial fishing are shown. Practical Value. The review may be useful for scientists, Ph.D. students, students, government authorities, and private entrepreneurs involved in the research process or exploitation of aquatic living resources in internal water bodies, primarily in the Kуiv reservoir.

Data of monitoring studies (2014–2016) on the state of hydrobionts in watercourses during the development of a hydrocarbon deposit on the Yamal Peninsula have been analyzed. The increased content of suspended solids has the greatest effect on hydrobionts. While the background values of concentration of suspended solids is 4–6 mg/L, in the area of the entrance of the pit effluents to the watercourses, their concentration increases up to 440 mg/L and higher. The effect of increased turbidity on the qualitative and quantitative indicators of planktonic organisms has not been found. An increase of suspended solids in water has a negative effect on zoobenthos (rSp = –0.426, p = 0.030 for the number of species; rSp = –0.590, p = 0.002 for the abundance; rSp = –0.480, p = 0.013 for the biomass) and fish (rSp = –0.567, p = 0.004 for ecological density of small fish species). Especially sensitive fish to the increased content of suspended solids are whitefishes and lake minnows. The most tolerant to turbidity are the nine-spined stickleback and Barbatula toni. Increased concentrations of suspended solids in autumn are the reason for the cessation of up-stream migration of whitefishes from the Gulf of Ob to the deep lakes. [ABSTRACT FROM AUTHOR]

Purpose. Investigate ecological conditions and determine fish productivity of ponds when growing young-of-the-year carp using a suspension of chlorella. Methodology. During the study, we used methods generally accepted in hydrochemistry, hydrobiology and fish farming. Findings. The article presents the results of the study on the use of chlorella suspension in the cultivation of carp. It was found that the use of chlorella suspension created favorable hydrochemical conditions resulting in intensive development of zooplankton, which had a positive effect on the growth of young-of-the-year carp and fish productivity of the pond. The development of the natural food supply was sufficient to meet the nutritional needs of juvenile carp. The average seasonal biomass of zooplankton in the experimental pond was 28.68 g/m3 that was 1.5 times higher than in the control. The share of cladocerans in the total biomass of zooplankton in the experimental pond was 76.6%, versus 36.8% in the control. The average biomass of zoobenthos for the growing season in the experimental was 1.3 times higher than in the control, and was formed by chironomid larvae, which are valuable in the food chain. Originality. The study investigated ecological conditions and fish productivity of growing ponds under conditions of the application of cattle manure and suspension of chlorella when growing carp in monoculture. Practical value. It was found that the use of chlorella suspension promotes the intensification of the development of zooplankton organisms in ponds. The obtained data can be used to develop practical recommendations for optimizing the conditions for growing carp seeds and increasing the biological productivity of ponds.

Purpose. To investigate the peculiarities of the formation of hydrochemical, hydrobiological regimes and to determine the fish productivity of nursery ponds under a complex exposure to their ecosystem. Methodology. The work was conducted according to generally accepted hydrochemical, hydrobiological and aquaculture methods. Findings. The article presents the results of the study on the productivity of nursery ponds when using a complex of intensification measures (fertilization with traditional fertilizers, application of chlorella paste, polyculture, and fish feeding). It was found that the main hydrochemical parameters during the rearing of cyprinid fingerlings were within the standard normal values ​​and were favorable for the development of prey organisms and the cultivation of fish seeds. Positive trends were obtained after the use of chlorella paste when growing juveniles of cyprinids in polyculture with different ratios of common carp and Chinese carps. The use of the chlorella paste in combination with other intensification measures in the experimental ponds created favorable conditions for the development of natural food supplies, growth and survival of cyprinid fingerlings. At the same time, the total fish productivity in the experimental ponds was 22.0-28.0% higher, and the feed costs were 1.1-1.3 times lower than in the control ponds. Originality. The peculiarities of the formation of hydrochemical and hydrobiological regimes have been investigated and the fish productivity of nursery ponds has been determined using cattle humus and chlorella pasta when growing young-of-the-year carp in polyculture with silver and bighead carp hybrids. Practical value. The obtained data can be used for developing practical recommendations regarding the optimization of the conditions for growing cyprinid seeds in polyculture using the chlorella pasta, increasing the efficiency of managing the state of aquatic ecosystems and their biological productivity.

The data on the taxonomic composition and quantitative characteristics of planktonic and benthic communities of the Lower Don in the area of construction of the Bagaevsky hydroelectric complex have been presented. In June – July 2018, a comprehensive hydrobiological survey was carried out to assess the taxonomic composition and quantitative characteristics of phytoplankton, zooplankton and zoobenthos. Hydrobiological samples were taken at 21 stations using standard techniques. The phytoplankton communities contained 110 taxa, zooplankton – 58, zoobenthos – 78. The spatial distribution of quantitative indicators of plankton and benthos in the investigated area has been presented. Phytoplankton abundance varied from 2,006.0 to 6,128.0 million cells/m3, biomass – from 1.00 to 7.37 g/m3, the average polygon indicators were 3,636.6 ± 223.5 million cells/m3 and 4.28 ± 0.39 g/m3 respectively. In terms of the number of registered taxa and quantitative indicators, two groups of phytoplankton dominated – cyanobacteria and green algae. The abundance of zooplankton ranged from 2,580 to 238,622 ind./m3, biomass ranged from 36.4 to 476.0 mg/m3, the average abundance was 74,690 ± 15,017 ind./m3 and 172.7 ± 24.8 mg/m3 respectively. Rotifers and cladocerans were the leaders in the number of species. Meroplankton was dominant in numbers (mainly due to mollusk larvae), and copepods were the dominant group in biomass. The number of bottom invertebrates varied from 20 to 17,867 ind./m2, biomass from 0.02 to 2,114.0 g/m2, the average zoobenthos abundance was 3,462 ± 898 ind./m2, biomass 133.9 ± 102.0 g/m2 respectively. The maximum number of taxa was recorded among crustaceans and chironomid larvae. The basis of abundance was formed by oligochaetes and insect larvae, mainly chironomids, mollusks dominated by biomass. The resulting materials can be used as background materials in assessing the impact of construction on the hydrobiological communities of the Lower Don

The results of long-term complex hydrobiological studies of the cooling pond of the South Ukrainian Nuclear Power Plant (SU NPP) are presented. The abundance of zoo- and phytoplankton increased until 1984–1985, and then in the summer of 1986, against a background of extremely high temperatures in the reservoir, there was a significant (32-fold) drop in the mean biomass of phytoplankton, coinciding with the minimum abundance of zooplankton. In subsequent years, the abundance of these groups recovered, but has not reached previous levels. At present, the zooplankton contains a considerable amount of thermophilic species. Research in recent years indicates that the zooperiphyton is dominated by the invasive gastropods Melanoides tuberculata (Müller, 1774) and Terebia granifera (Lamarck, 1822). In the epiliton, the number of LDT (lowest determined taxa) and groups of invertebrate was more than double that in the epiphyton (17 and 7, respectively). At the first stages of the development of the pond ecosystem, the periphyton communities were dominated by zebra mussel Dreissena polymorpha Pall. These communities were eliminated as temperature increased, and after the commissioning of the NPP, the second and third power units were not completely restored in the environment of a constantly high thermal load. Over years, with the formation of bottom biotopes, the abundance of zoobenthos increased, and with an increase in the technogenic load, it decreased. At the present stage, the zoobenthos is impoverished (9 taxa) and is dominated by mainly juvenile tubificids.

Objective.To determine the energy value of several groups of the East Antarctic sea biota and identify potential calorific differences in the context of both taxa and ecological groups. Methodology. Sampling was carried out by traditional methods (benthic traps, diving gathering), and remote sampling was also applied (using remote-controlled underwater vehicles). The energy value of organisms is determined using wet burning methods. Results. The energy indicators of the main biological objects of the sublittoral of the three seas at the East Antarctica were determined for the first time. It has been shown that in the studied sublittoral regions of the Cosmonauts, Cooperation (more Sodruzhestva) and Davis seas, the dominant species of marine zoobenthos was the sea urchin Sterechinus neumayeri (Meissner, 1900). The caloric values of starfish, polychaetes, nemerteans, sponges, ascidia, holothurians, crustaceans, and some other taxa of marine biota were determined. It is shown that the content of organic matter in Antarctic species varies from 12—94%, and caloric content — from 0.7—7.3% cal / mg dry matter, with the maximum values registered for amphipods and calanoids. The energy equivalents of marine zoobenthos per unit of bottom square have been calculated. The ratio equation of the caloric content of the substance of the studied object to the ash content is calculated. Conclusions. In general, we can conclude that the caloric values of marine zoobenthos in all three studied seas are close to each other. Furthermore, the caloric content of individual representatives of marine fauna varies significantly and, in general, depends on the quantity and quality of organic matter in certain species as well as on the season of year. The low-caloric representatives of the Antarctic flora and fauna correspond to the high substance ash levels of their body. Depending on the energy value significance, several groups of marine biota were represented, represented by various taxa.

The Veselovskoe reservoir is among the most productive reservoirs of the Manych Cascade. Sharp changes in the hydrological and hydrochemical conditions of aquatic animals' habitat have been typical for the reservoir since its formation. During the intensive succession processes taking place in the reservoir, a restructuring of the plankton and benthos communities was observed accompanied by significant fluctuations in their quantitative indicators. In 2016, there were conducted complex hydrological and biological studies of the reservoir in order to assess the structure of phytoplankton, zooplankton and zoobenthos at the present stage. The western part of the reservoir as the most productive was studied in the autumn by applying standard techniques. According to the data obtained, the phytoplankton abundance averaged 198.1 mln cells/m3, and their biomass constituted 149.1 mg/m3 in the region under discussion, with diatoms and cryptophytes dominating in the phytoplankton community. The abundance of zooplankton averaged 15,298 ind./m3, and its biomass was 42.3 mg/m3. Rotifers dominated in the zooplankton by number, while cladocera and copepods played a key role in the biomass. The zoobenthos number and biomass amounted, respectively, to 3,141 ind./m2 and 7.4 g/m2, the basis of the benthic fauna of the reservoir was formed by oligochaetes and chironomids, whose abundance was predominant, as well as by mollusks that predominated in biomass. Studies of recent decades have revealed a decrease in the phytoplankton and zooplankton biomass in the Veselovsky reservoir. After the successful acclimatization of benthic invertebrates of the Caspian estuary complex and the penetration into the reservoir and development of invasive species, primarily the Dreissena, the abundance and biomass of the bottom community have stabilized and are maintained at a high level due to the malacofauna development

Purpose. Creation of a thematic bibliographic list of publications on the use of classical and modern methods for studying the biota of water bodies - bacterio-, phyto-, zooplankton, zoobenthos, higher aquatic plants. 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 150 sources covering the time interval from 1949 to 2017, and devoted to the development and application of methods for studying aquatic biocenoses, their individual components and productive characteristics has been composed. 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 list may be useful for scientists, practitioners, students, whose area of interests covers the questions of hydrobiology, hydroecology, zoology and aquaculture.

Biodiversity of aquatic organisms is formed under the influence of not only natural, but also anthropogenic factors. In this work, the influence of the flow velocity, river size, flow regulation and urbanization on various groups of aquatic organisms was studied in several lowland rivers. The study was conducted in 2013 on six tributaries of the Upper Sukhona River. Five sampling sites were in different parts of the Vologda River and five sites on small rivers, Losta, Lukhta, Komya, Chernyj Shingar, and Belyj Shingar (one site per river). Phytoplankton, zooplankton and zoobenthos were sampled six times, from April to October, and macrophytes were studied in August. In total, 469 species of aquatic organisms were found in the tributaries of the Upper Sukhona River, belonging to the following phyla: Cyanophyta (5 species), Chrysophyta (8), Bacillariophyta (62), Xanthophyta (1), Cryptophyta (10), Dinophyta (4), Euglenophyta (12), Chlorophyta (17), Streptophyta (1), Bryophyta (2), Marchantiophyta (3), Equisetophyta (1), Magnoliophyta (63), Rotifera (22), Cnidaria (1), Platyhelmintes (1), Annelida (29), Mollusca (33), Arthropoda (194). The maximum number of species was found in the Vologda River, the largest of all the tributaries. The number of zoobenthos species was similar at different sites in the Vologda River and in the small rivers. The number of species of other groups of aquatic organisms in the small rivers was lower than those registered in the Vologda River. The greatest number of macrophyte and zoobenthos species was recorded in the Upper Vologda River and Belyj Shingar River, where the flow is strong all the year round. The greatest number of phyto- and zooplankton species was found at the extra-city sites where current is almost absent. In the dam backwater, species richness was higher than that registered downstream of the dam. At the same time, the species richness of macrophytes and zoobenthos in the dam backwater was lower. The smallest number of species was found in the Vologda River, downstream of the city of Vologda. Decreases in the species richness and Shannon’s biodiversity index were witnessed in the Vologda River city site and in the small rivers, as they get closer to the city. Cluster analyses performed for the studied groups of aquatic organisms showed dissimilar results; however, the studied sites on the Vologda River having the highest anthropogenic load formed a cluster. Aquatic organisms of the Upper Sukhona tributaries experience both natural (flow velocity and size of the watercourse) and anthropogenic factors (proximity to the city and flow regulation).

Aquatic part of Khmelnitsky Nuclear Power Plant teсhnoeсosуstem was studied during the periods of operation of one (1998–2001) and two power units (2005–2016). Changes in species composition, as well as abundance and biomass dynamics of phytoplankton, zooplankton, zoobenthos, zooperiphyton, and higher aquatic plants in the cooling pond and channels were found to be related to both technogenic and biogenic factors. The invasion of alien species constantly occurred in the teсhnoeсosуstem. Thirteen invader species were noted during the period of research. Invasion of Zebra mussel (Dreissena polymorpha) and submerged plant Najas marina prevented regular operation of the system; sponge Eunapius carteri reached mass development. Some invaders appeared for a short period; others naturalized, but did not reach the mass development. The phenomenon of contourization associated with the invasion and the mass development of the powerful filter feeder – Zebra mussel was observed in the ecosystem during the period of research. Signs of contourization (for example, a significant increase of water transparency) were observed already in years 2–3 after the invasion of the clam; significant changes in the pelagic subsystem were observed only in years 5–6. At the time of the invasion of the second dreissenid species (D. bugensis), population of D. polymorpha was in the stage of stabilization at low level of abundance. The assumption of the possible outbreak of D. bugensis abundance during the first years after its invasion was not confirmed. Thus, the successional processes in the teсhnoeсosуstem are determined not only by technogenic and natural abiotic, but also biotic factors

Species-area relationships (SAR) for aquatic invertebrates and phytoplankton were investigated in several shallow lakes from the Fizeș River catchment area. The lakes differed in their morphometric, physical-chemical, biotic and habitat characteristics, with two constant distinctive clusters: the lakes from the main river course, highly exploited for fish farming and generally characterized by higher organic and nutrient loads, and the lakes from the river tributaries, with better environmental conditions, increased depth and lower exploitation intensities. Lake area was a poor predictor of taxon richness for lacustrine invertebrates. Low-intensity exploitation regime, the presence of submerged vegetation, lake depth and natural land use in the catchment area represented the most important independent variables explaining the number of taxa for both planktonic and benthic invertebrates. In case of phytoplankton, however, lake area was an important predictor for taxon richness. Our results represent the first holistic approach to investigating SAR patterns of aquatic biota in natural and man-made lakes from the region. [ABSTRACT FROM AUTHOR]

Purpose. To investigate the effect of the bacterial fertilizer "Phosphobacterin" on the formation of the hydrochemical regime, development of the natural food supply and fish productivity in the growing ponds. Methodology. The work was conducted according to generally accepted hydrochemical,, microbiological, hydrobiological and fish farming methods. Findings The article presents the results of a study of the productivity of growing ponds with different methods of the application of the bacterial fertilizer "Phosphobacterin". It was found that the hydrochemical regime of the experimental ponds was formed under the effect of the source of water supply and measures aimed at intensifying the development of the natural food supply and was favorable for the development of feed organisms and the cultivation of fish seeds. Application of the bacterial fertilizer at the beginning of the growing season along the water pond surface proved to be little effective for increasing the productivity of the pond ecosystem as a whole. A more effective method of increasing biological productivity, including fish productivity of growing ponds, was the application of "Phosphobacterin" during the growing season both on the bed and on the water surface in combination with the organic fertilizer - cattle humus. In the experimental pond under complex fertilization, the average phytoplankton biomass during the growing season was 1.5 times, bacterioplankton 1.1 times, zoobenthos 2.6 times higher, and the obtained total fish productivity was 1.2 times higher than in the control pond (when applying only cattle humus). Originality. The peculiarities of formation of hydrochemical and hydrobiological (phyto-, bacterio-, zooplankton, zoobenthos) regimes of growing ponds and the fishery indices are studied, both for bacterial fertilizer "Phosphobacterin" independently and together with the traditional organic fertilizer - cattle humus. Practical value. Based on the obtained results, we developed temporary recommendations for using the bacterial fertilizer "Phosphobacterin" to increase the productivity of growing ponds.

The water level variations of the Lake Balkhash, the Kapshagay Reservoir and the Ili River and the linkage with salinity and biological conditions are investigated in this work using different techniques: satellite radar altimetry, in situ gauges, historical archives of fish population counting and field works. We show that it is possible now to monitor, over decades, in near real time, with high precision, the water level changes in the Lake Balkhash from satellite altimetry, over the reservoir and also along the Ili River. The vulnerability of the lake fauna and flora populations is enhanced by the morphometry of the lake: shallow and separation of the eastern basin from the western basin through the narrow Uzun‐Aral strait. Water policy of the Ili River also plays a fundamental role in the evolution of the Balkhash Lake. The Ili River that provides 80% of the surface water of the lake is a transboundary river. Development of intense irrigated agriculture in the upstream part of this river, located in the Chinese territory, could lead in the future to high hydrological stress in the downstream regions with potentially high damage in the delta and for fishery production. We show here the recent evolution of the Lake Balkhash basin from satellite data. Some interannual oscillation of 6–8 years over the last decade has been highlighted, with a water level of the lake still at a high value, but prediction on increasing irrigation is also highlighting the vulnerability of this lake. Linkage between water level change along the river and the downstream waters is also investigated. It shows that the role of the reservoir is not fundamental in the understanding of the Lake Balkhash water level changes which is in contrast highly correlated to upstream river level changes. [ABSTRACT FROM AUTHOR]

The construction of hydrogeological cities in China has attracted attention from researchers worldwide. This study surveyed the major urban hydroecological river channels and selected 59 stations for hydroecological field sampling. The Ecopath model was used to screen for key river species, and niche analysis was performed to study the niche breadth and overlap between the key species and water quality factors. Sixteen key fish species were screened out; Pseudorasbora parva had the highest niche breadth (2.952). Of the 16 screened key species, Carassius auratus had the largest niche overlap (11.977). Seven key zooplankton species were screened out. Phryganella nidulus had the highest niche breadth (2.070). Of the seven screened key species, P. hemisphaerica had the largest niche overlap (9.065). Of the nine screened key species, Bithynia fuchsiana had the largest niche overlap. These findings provide a reliable theoretical basis for ecological restoration, and serve as a methodological reference for sustainable water resources management. Niche analysis was performed to study the niche breadth and overlap between key species and water quality factors. The results of the study provide a reliable theoretical basis for ecological restoration and water resources management. [ABSTRACT FROM AUTHOR]

Highlights • We present large-scale and long-term monitoring data on four aquatic bioindicators. • All bioindicators assessed similarly variation in water quality at small scale. • Phytoplankton and zooplankton showed opposite trends over time. • We show evidence for generally decreasing water quality in Russia. Abstract Scale-related assessment strategies are important contributions to successful ecosystem management. With varying impact of environmental drivers from local to regional scales, a focal task is to understand scale-dependent responses when assessing the state of an ecosystem. In this study we use large-scale monitoring data, spanning 40 years and including four aquatic bioindicator groups (phytoplankton, zooplankton, periphyton, zoobenthos) to expose the long-term changes of water quality across Russia. We include four hierarchical spatial scales (region, basin, waterbody and observation point) to identify the relative importance of different spatio-temporal scales for the variation of each bioindicator and patterns of co-variation among the bioindicators at different hierarchical levels. We analysed the data with Hierarchical Modelling of Species Communities (HMSC), an approach that belongs to the framework of joint species distribution models. We performed a cross validation to reveal the predictive power of modelled bioindicator variation, partitioned explained variance among the fixed effects (waterbody type, and influence of human population density) and the random effects (spatial and spatio-temporal variation at the four hierarchical scales), and examined the co-variation among bioindicators at each spatio-temporal scale. We detected generally decreasing water quality across Russian freshwaters, yet with region and bioindicator specific trends. For all bioindicators, the dominating part of the variation was attributed the largest (region) and smallest (observation point) hierarchical scales, the region particularly important for benthic and the observation point for pelagic bioindicators. All bioindicators captured the same spatial variation in water quality at the smallest scale of observation point, with phytoplankton, zooplankton and periphyton being associated positively to each other and negatively to zoobenthos. However, at larger spatial scales and at spatio-temporal scales, the associations among the bioindicators became more complex, with phytoplankton and zooplankton showing opposite trends over time. Our study reveals the sensitivity of bioindicators to spatial and temporal scales. While delivering unidirectional robust water quality assessments at the local scale, bioindicator co-variation is more complex over larger geographic scales and over time. [ABSTRACT FROM AUTHOR]

Purpose. To analyze scientific sources on the studies of toxic and lethal concentrations of pesticides on phytoplankton, zooplankton, zoobenthos and fish in current conditions of Ukraine. Findings. A review of works of a variety of scientists showed that pesticides with different chemical origins have disastrous effects on everyone without the exception of freshwater biota organisms. The article highlights the peculiarities of the toxic effects of pesticides of major chemical groups, which are used or stored in Ukraine. Their toxic and lethal concentrations for the major species of phytoplankton, zooplankton, zoobenthos and ichthyofauna reservoirs are considered. The data on basic features of behavioral reactions of aquatic organisms on poisoning by pesticides are provided. The basic structural and systemic diosrders of homeostasis of the organisms of aquatic biota are described. The effect of pesticides on phytoplankton needs further research, however, is was found that they have common feature as the disturbace of photosynthesis process and accumulation. In turn, this provoques kills in water bodies and poisoning of phytoplanctivorous fish. Zooplanktonic organisms are highly sensitive to pesticides; hence they can be used as an indicator of the state of fresh water. It was found that, pesticides depending on their concentration have different toxic effects on zooplankton organisms. The effect of pesticides on benthic organisms was little investigated. It is known that benthic communities respond to the presence of pesticide by changes in species composition, number of species, abundance and biomass of benthos in general and individual taxonomic groups of benthic invertebrates. The toxicity of pesticides for fish depends on their chemical nature, the form of the preparation, dose, fish species and age, water temperature and the content of oxygen and salts. In particular, juvenile fish are much more sensitive to the chemicals, and an increase in water temperature and a decrease in oxygen content results in an increase in pesticide toxicity. Practical value. The array of the generalized information on the toxic and lethal effects of pesticides will be important for scientists who investigate the biological risk of pesticides and their impact on basic categories of freshwater biota and, in general, for ichthyological and environmental research. The information on the peculiarities of the toxic effects of pesticides on fish is important in the conditions of increasing demand for fish products as a source of valuable proteins for humans.

Aim. As a result of fluctuations in water level, waves, circulation, rise and fall of the water levels there are constant partial erosion and leaching of soil banks in water bodies, with intensive ongoing pollution of the waters of the Caspian Sea, which we have seen in recent decades, and in the long run may dangerously affect the transparency of the water and reduction of biomass of the benthic community in the western part of the South Caspian Sea. The paper presents the results of the last 60 years of monitoring studies to determine the nature of transparency, depth of the euphotic layer, the primary production of phytoplankton photosynthesis, phytoand zoobentos biomass and destruction of organic matter in the coastal western shelf of the South Caspian. Methods. In the course of research, modern methods of quantitative and qualitative analysis were used, regulated by normative documents, duly approved for environmental monitoring of water bodies. Results. Studies have shown that since the second half of the 90’s, the mainland coast strip is strongly deformed, starting from the village of Shihva to Kura area, further from the south of the village of Narimanabada to Astara. Dozens of artificial coves, bays, islands were created with clay-soil mounds. Conclusions. A huge mass of clay and soil goes to the coastal waters of the western shelf as a result of the destruction of the structure of the coasts due to waves and wind, resulting in clastic particles in the water increased by 2.5 3 times, the transparency of the water in the area of 5-10 m depth contours is reduced by more than 2 fold, increasing the degradation 1.6 times. During this period, because of the intensity of sedimentation and the overall pollution in the study area, phytobenthos has almost disappeared and flowering has been reduced by 7580%. Zoobenthos has been badly damaged and biomass of bento detritivorous organisms has also been reduced.

In the article, the results of the studies of the present state of freshwater ecosystems and their biotic components in the western part of the Yamal Peninsula are presented. Based on the evaluation of the structure of the communities of phytoplankton, zooplankton, benthos and whitefishes, the range of the problems related to the protection of biological resources at the development of the Kruzenshternskoye gas field is defined. Data on species composition and quantitative indicators of hydrobionts of different types of waterbodies and watercourses in the lower reaches of the Mordyyakha and Naduyyakha rivers basins are the basis for environmental monitoring of water objects at development and exploitation of the Kruzenshternskoye gas field. According to the monitoring program, evaluation of the fish fauna state and their food base on the territory of the Kruzenshternskoye gas condensate field (GCF), is present. The zones of rivers deltas are the most important areas of the salmonid and whitefishes valuable fish species feeding at the territory of Kruzenshternskoye GCF. In the cases where complete demolish of waterbodies and watercourses for construction of facilities for GCF does not occur, changes of quantitative and qualitative characteristics of communities of hydrobionts after cease of works are reversible. River ecosystems are restored within a more short period of time in comparison to lacustrine ones. On the basis of conducted comprehensive studies, the proposals for the protection of fisheries resources and monitoring of aquatic ecosystems are reported. Recommendations for reducing the anthropogenic impact on aquatic ecosystems in the development period are presented. The results of the investigation were used in the designing the environmental protection part of the Kruzenshternskoye deposit project. At present, the disturbances in the territory of Kruzenshternskoye deposit of gas does not impact the aquatic ecosystems

Purpose. To assess the development of main components of natural forage base in nursery ponds during the period of rearing the carp fish seeds in monoculture. Methodology. Hydrobiological (bacterioplankton, phytoplankton, zooplankton, zoobenthos) and hydrochemical samples have been collected and processes according to generally accepted methods. Findings. Qualitative and quantitative parameters of the development of bacterio-, phyto-, zooplankton and zoobenthos in nursery ponds have been studied when rearing young-of-the-year Lubin few scale carp, Antoninsko-Zozulenets carp and their reciprocal crosses in monoculture (50 thousand fish/ha). General water mineralization in ponds was 292.7–315.7 mg/dm3 and according to O.A. Alekin’s classification, pond water belonged to hydrocarbonate class of calcium group. Water pH was 7.4–7.5. Permanganate values were 12.5–14.9 mgO/dm3. On average, average ammonium nitrogen content, nitrite nitrogen and nitrate nitrogen, mineral phosphorus, total iron did not exceed normative values. Qualitative and quantitative parameters of phyto-, bacterio-, zooplankton of nursery ponds have been studied. The seasonal development of phytoplankton was within 15.96–20.88 mg/dm3 with the predominance of Chlorococcales in the floristic spectrum. The development of bacterioplankton was within 5.08–5.81 mg/dm3. Zooplankton was dominated by cladoceran-copepod complex with average seasonal values of 5.27–17.20 g/m3. Zoobenthos was formed of Diptera larvae (Chironomidae and Chaoboridae) with average seasonal biomasses of 0.51–1.8 g/m2. According to saprobic parameters, pond water belonged to β-mesosabrobic zone and corresponded to the water quality class II (“clean enough” category). Fish productivity of nursery ponds was within 617.2–815.2 kg/ha; output of carp young-of-the-year was within 39.82–43.56%, mean weight of young-of-the-year was 31.0–39.3 g. Originality. For the first time we carried out a comprehensive assessment of the natural forage base in nursery ponds when rearing carp fish seeds in the conditions of forest-steppe zone of Vinnitsa region at the fish farm “Merkuriy”. Practical value. The obtained data allow rearing high quality young-of-the-year Lubin few scale carp, Antoninsko-Zozulenets carp and their reciprocal crosses.

The paper summarizes the results of integrated study of current state of freshwater biota of small water bodies, located in the area of ‘Fedorova tundra’ intrusion. A list of species composition is given, quantitative and structural indicators of phytoplankton, zooplankton, zoobenthos and fish are assessed. Size-weight, age and sex structure of dominant ichthyofauna are estimated. The obtained results can be used as the reference values for further monitoring of the ecological status of the water bodies.

Purpose. To investigate the effect of brewer᾽s grains on formation of hydrochemical regime, development of natural forage base, and fish productivity in nursery ponds. Methodology. Generally accepted methods for hydrochemistry, hydrobiology and fish farming have been used. For general (full) chemical analysis, water samples were taken 2 times a season (at the beginning and end of the growing season), a short chemical analysis of water was conducted twice a month. Hydrobiological samples (phytoplankton, zooplankton, zoobenthos) were collected before and after the application of organic fertilizers and throughout the growing season 2-3 times a month. Findings. The article summarizes the results of studies conducted during 2007-2009 devoted to the use of different doses and schemes of application of brewer’s grains in nursery ponds. Effects of brewers’ grains of hydrochemical regime, development of natural food base (phyto-, zooplankton, zoobenthos) and fish productivity in nursery ponds have been studied. It was found that the brewer᾽s grains stimulates the development of natural forage base for juvenile fish and can be an alternative to traditional organic fertilizers ― humus. Adding of brewers’ grains (dry matter content of 29,4 %) to the nursery ponds at the rate of 2,0 t/ha (once or twice during the growing season) ensured the development of phytoplankton to 33,52 dm3, zooplankton ― up to 37,97 g/m3, benthos ― up to 3,43 g/m2. Fish productivity in nursery ponds production reached 736,3 – 754,6 kg/ha. Originality. Peculiarities of formation of hydrochemical regime and development of phyto-, zooplankton, and zoobenthos have been studied for the first time when using wastes of the brewery industry – brewer’s grains for fertilization of nursery ponds. It was found that brewer᾽s grains contribute to an increase of the development of natural forage base and fish productivity in ponds. Practical Value. Based on these results, it was proposed to put into practice the use of pond fish brewer᾽s grain, as non-traditional organic fertilizers, to stimulate the development of natural forage base nursery in ponds to enhance their fish productivity.

The Neva Estuary situated in the eastern part of the Gulf of Finland is one of the largest estuaries of the Baltic Sea. At present, heavy nutrient and organic matter loading, mainly from the Neva River and point sources in the upper estuary are the most serious environmental problem for the Neva Estuary and adjacent parts of the eastern Gulf of Finland. Long-term studies of mid-summer primary production and mineralization of organic matter were conducted in upper and middle parts of the Neva Estuary. A considerable increase of production and biomass of phytoplankton was observed in the middle part of the estuary during the last decades mainly due to an increase in biomass of cyanobacteria. However, they are mostly concentrated in the upper water layers and only a small part of them reached the near bottom water layers and may be used as a food by zoobenthos. The mineralization of organic matter in the water column was twice higher than primary production that indicates the importance of allochthonous organic matter in the carbon budget of the both parts of the estuary. The carbon isotope signature of seston and most of the zoobenthic species in the upper part of the estuary was close to the signature of allochthonous carbon leaking from watershed (− 27‰). Higher values of δ 13 C of seston in the upper mix layer of the Middle estuary indicate intensive primary production in mid-summer. The carbon isotopic signature of zoobenthos in this part of the estuary was also in general lower than in the Neva Bay reflected higher importance of autochthonous organic matter in food webs of the estuary. [ABSTRACT FROM AUTHOR]

In order to reveal the differentiated responses of plankton and zoobenthos to water quality on both annual and seasonal time scales, an ecological study on plankton and zoobenthos community was conducted during 2011 to 2015 in Nansi Lake in northern China. Different dynamics were found among phytoplankton, zooplankton, and zoobenthos in terms of density, biomass, and biodiversity. On an annual time scale and with deterioration of water quality, density and biomass of plankton and zoobenthos showed different variations, while phytoplankton (density, biomass, and biodiversity) changed significantly when water quality improved. On a seasonal time scale, density and biomass of phytoplankton showed significant differences between spring and summer. Results of Pearson's correlation analysis revealed that phytoplankton, zooplankton, and zoobenthos were significantly affected by different environmental factors. Our study demonstrated that phytoplankton was more sensitive to water quality changes than zooplankton and zoobenthos. These results suggest that density and biomass of phytoplankton could rapidly reflect water quality, whereas biodiversity of phytoplankton could indicate long-term status of water quality combined with the physico-chemical parameters of water. The results could contribute to predicting the dynamics of plankton and zoobenthos in freshwater lakes and to selecting effective bio-indicators for ecosystem health assessment of freshwater lakes. [ABSTRACT FROM AUTHOR]

Multidisciplinary studies were carried out in the Lower Don River in the low-water November of 2012. The studies showed relatively low concentrations of oil products (up to 2 MAC) and heavy metals (up to 1 MAC), which were likely due to the cessation of navigation in the river. However, copper concentration was found to be in excess of its MAC. The most polluted were found to be the port water areas of the cities of Volgodonsk, Ust'-Donetsk, and Semikarakorsk. The distribution of nutrients over streams is uneven: the Don water is poorer in nutrients than the waters of the Severskii Donets and the Manych are. Oxbows can serve as depots of organic matter, where it accumulates over longer periods than in the river. The residual manifestations of the summer-autumn blooming of blue-green algae, observed in shallows, the predominance of algae of divisions Cryptophyta and Bacillariophyta (typical representatives of winter planktonic algacenosis), and their low abundance suggest the transitional state of phytoplankton communities to autumn-winter season (pre-winter period). The species diversity and biomass of zooplankton were largest in the Don R. and lowest in the Severskii Donets R. The formation of zooplankton species composition shows the effect of the runoff from the Tsimlyanskoe Reservoir. An increase in the proportion of oligochaetes and invading species was recorded in the Don. The decrease in the diversity of benthos is attributed to natural factors, i.e., the decay of imago and thicket forms in autumn. The biomass of the soft (food) benthos is low because of the predominance of its small-size forms. [ABSTRACT FROM AUTHOR]

Three alpine lakes (Oiskoe, Karovoe, Raduzhnoe) of mountain range Ergaki were sampled in 11- 15 September 2008. Species (taxonomic) composition, number of species, abundance and biomass of phytoplankton and zooplankton, phytobenthos and zoobenthos of each lake were studied for the first time. Coefficients of species similarity of plankton and benthos assemblages between lakes were calculated. Results of fishing in the lake Oiskoe were presented. As found, species diversity of plankton and benthos assemblages of the lakes were low and the lowest one was in the fishless lake Karovoe. Similarity of species composition between lakes were low (0,09-0,40). Biota of the lakes in general consisted of species with widespread distribution, with the exception of some species, namely Alona werestschagini Sinev known (in Russia) from Altai and north of Europe only, and Arctodiaptomus dahuricus Borutzky known from Transbaikalia. Thus areals of these species were expanded, but Arctodiaptomus may be a new species (subspecies) Despite of the low abundance and biomass of phyto- and zooplankton (characteristic of oligotrophic lakes) and low or moderate zoobenthos biomass (characteristic of oligotrophic-mesotrophic lakes), catched individuals of fish Thymallus arcticus Pallas were fat (mark 3-4) and their guts were filled. Apparently food supply is sufficient for good fitness of the existed grayling population.

Grass carp (Ctenopharyngodon idella Val.) stocked (29 kg/ha) in a small pond reduced the biomass of aquatic macrophytes from 109 g/m2 to 33 g/m2 during one growing season. The only changes in hydrochemical parameters (pH, alkalinity, acidity, BOD5, CODMn, NH4-N, NO2-N, NO3-N, TN, PO4-P and TP) associated with the grass carp stocking were a decrease in pH (from 8.43 to 7.57) and in NO3-N concentration (from 0.99 mg/l to 0.56 mg/l). The increases in organic matter content and NO3-N concentration in the surface sediment layer were higher in the control pond than in the pond stocked with grass carp. No changes were detected in the other parameters (NH4-N, PO4-P and TP) in the upper sediment layer and between all parameters measured in the lower inorganic layer. The grass carp grazing had no impact on phytoplankton biomass (concentration of chlorophyll-a) or species composition. There were no changes either in the abundance or in the species composition of zooplankton and zoobenthos induced by grass carp. Statistically significant indirect changes (in water and sediment chemistry) following the grass carp stocking were connected especially with a reduction in the biomass of the filamentous alga (Cladophora globulina) or rather with its maintenance in the control pond.

Coastal areas are among the most biologically productive aquatic systems worldwide, but face strong and variable anthropogenic pressures. Few studies have, however, addressed the temporal development of coastal ecosystems in an integrated context. This study represents an assessment of the development over time in 13 coastal ecosystems in the Baltic Sea region during the past two decades. The study covers between two to six trophic levels per system and time-series dating back to the early 1990s. We applied multivariate analyses to assess the temporal development of biological ecosystem components and relate these to potential driving variables associated with changes in climate, hydrology, nutrient status, and fishing pressure. Our results show that structural change often occurred with similar timing in the assessed coastal systems. Moreover, in 10 of the 13 systems, a directional development of the ecosystem components was observed. The variables representing key ecosystem components generally differed across systems, due to natural differences and limitation to available data. As a result of this, the correlation between the temporal development of the biological components in each area and the driving variables assessed was to some extent area-specific. However, change in nutrient status was a common denominator of the variables most often associated with changes in the assessed systems. Our results, additionally, indicate existing strengths as well as future challenges in the capacity of currently available monitoring data to support integrated assessments and the implementation of an integrated ecosystem-based approach to the management of the Baltic Sea coastal ecosystems. [ABSTRACT FROM AUTHOR]