CONTENT
Environmental Concerns and the State of Aquatic Environment
Studying the impact of the Temernik River on the water quality in the lower reaches of the Don River
Knyazeva T.V., Tambieva N.S.
Abstract
Background. The water quality of the Don River, one of the largest rivers in the European part of Russia, is comprehensively assessed annually by processing data from the state monitoring network and, based on the results, is assigned to the 2nd – 4th classes, being characterized in the range from “slightly polluted” to “contaminated”. Its right tributary, the Temernik River, which flows through the industrial metropolis of Rostov-on-Don and experiences a severe, constantly changing anthropogenic load, greatly contributes to the pollution of the Lower Don River, major part of which is comprised by heavy metal (HM) compounds. Relevance. When metal compounds enter natural waters, they do not undergo biodegradation and, in various physical and chemical forms and concentrations, can cause harm to the aquatic ecosystem components, which necessitates the monitoring of water quality and identification of the content of ecotoxicants. The aim of this research is a long-term study of the distribution dynamics of the heavy metal compounds in the water of the urbanized section of the Temernik River to assess their impact on the quality of the Don River water. Methods. Quantitative determination of mass concentrations of heavy metal compounds in water, as well as suspended solids and dry residue (an indicator of total water mineralization), was conducted using methods developed at the Hydrochemical Institute. Results. In the water samples taken in the Temernik River within the urban agglomeration and at the confluence with the Don River, the mass concentrations of heavy metals (both in their dissolved form and their total (gross) content), as well as dry residue and suspended solids, were determined. The degree of water pollution with heavy metal compounds was assessed based on identifying the exceedance of the mass concentrations of dissolved forms over the corresponding MACs. To investigate the transport patterns of heavy metal compounds, the quantitative ratios between their suspended and dissolved forms were calculated. Conclusion. Long-term analysis of the obtained data reliably demonstrated the negative impact of the Temernik River on the waters of the Lower Don River.
Keywords: water, Temernik River, Don River, pollution, heavy metals, transport forms, mineralization
Biology and Ecology of Aquatic Organisms
Dynamics of aerobic and anaerobic microperiphyton formation in a pilot installation of a hydrobiological purification system
Doroshenko Yu.V., Burdiyan N.V.
Abstract
Background. The fuel oil spill, which occurred after a tanker accident in the Kerch Strait in December 2024, caused considerable damage to the Black Sea ecosystem. Relevance. Due to the recent events, the installation of hydrobiological purification systems (artificial reefs) in the coastal waters of the Black Sea has become an urgent issue. These systems are based on the natural processes of self-purification of the marine environment, including the removal of oil hydrocarbons. The aim of this work was to study the features of the formation of some physiological groups of the aerobic and anaerobic bacterial community of macroperiphyton in a hydrobiological purification system (HPS). Methods. Sampling and subsequent processing of the material were carried out in accordance with standard methods used in hydrobiology and general microbiology. Results. It was found that, in the annual cycle of observations, the abundance of heterotrophic and hydrocarbon-oxidizing bacteria in the macroperiphyton formed on the installed netting components of the HPS is several times higher than in seawater, both near the HPS and at some distance from it. The degradation of organic matter in the HPS involving the oxygen was generally accompanied by its anaerobic transformation. No seasonal differences in the quantitative content of anaerobic bacterial groups were observed. Conclusion. Bacterial activity (ability to process and remove organic compounds) is moderately higher in the vicinity of the experimental system installation than at a distance from it and significantly increases within the periphyton of the netting components of the system, which confirms the high sorption capacity of the periphyton of the hydrobiological purification system and its crucial role in the self-purification processes in this water area.
Keywords: bacteria, hydrobiological purification systems (artificial reefs), Black Sea
Ichthyofauna of Marine and Inland Water Bodies
The first capture of whiting Merlangius merlangus (Linnaeus, 1758) in Taganrog Bay of the Azov Sea
Luganskaya A.V., Nebesikhina N.A., Luzhnyak V.A.
Abstract
Background. Due to the ongoing increase in the salinity of the waters of the Azov Sea and Taganrog Bay, an expansion of the habitat of many marine fish species has been observed in this area. Relevance. Some species invade the water bodies where they have not been previously recorded, which indicates an expansion of their range and changes our understanding of their ecological characteristics and environmental limiting factors. The aim of this work is to describe the first record of whiting Merlangius merlangus in Taganrog Bay. Methods. The first capture of whiting in Taganrog Bay occurred in the course the ichthyoplankton and zooplankton surveys conducted with a lampara net in the Azov Sea by the employees of the Azov-Black Sea Branch of the State Research Center of the Russian Federation FSBSI “VNIRO” (“AzNIIRKH”). Results. A detailed morphological description of the caught specimen is provided. Comparison of the nucleotide sequence of the COI gene region of mitochondrial DNA with data from the gene bank indicates that the investigated specimen belongs to the species M. merlangus. Conclusion. The observed trend of expansion of the range of some marine fish species in the Azov Sea Basin and their new findings in the water bodies where they had not been previously recorded result from the ongoing increase in the water salinity of the Azov Sea and Taganrog Bay.
Keywords: whiting Merlangius merlangus, range, Taganrog Bay, gene, COI mtDNA
Features of the haematic profile of the Caspian roach Rutilus rutilus caspicus (Jakowlew, 1870) in the Volga-Caspian Region
Terpugova N.Yu., Konkova A.V., Grushko M.P., Fayzulina D.R.
Abstract
Background. Haematological parameters of fish can serve as indicators for assessing the condition of water bodies, since fish blood is very responsive to environmental changes. Relevance. The decline of the Caspian roach stocks necessitates a more in-depth analysis of its physiological state. The aim of this work is to study the haematological profile of juvenile Caspian roach and its mature individuals in the time ranges characterized by different water content. Methods. The analysis of the blood cellular structure of the investigated fish specimens was carried out in accordance with the methods generally accepted in ichthyohaematology. Results. During low-water periods, an increase in the number of blast and maturing cells is observed. In high-water periods, mature erythrocytes and lymphocytes predominate, reflecting more stable environmental conditions. Haematological parameters in mature Caspian roach were at the upper limits of the norm, including a slight increase in the proportion of pathologically altered erythrocytes. Cytometric studies revealed that mature erythrocytes in mature fish have a more elongated shape compared to similar cells in juvenile Caspian roach, which leads to an increase in the cell surface area by 1.5 times. Conclusion. Haematological parameters of juvenile Caspian roach vary depending on hydrological conditions, which indicates the body's reactions to stress factors. The established differences in the haematological profiles of juveniles and mature individuals serve as indicators of changes in the aquatic environment and can be used in the assessment of the state of water bodies.
Keywords: Caspian roach, influence of river runoff volume, Volga River Delta, blood cells, leukocyte formula, juveniles, erythrocyte pathologies, erythrocyte cytometry, erythropoiesis
Fisheries and Processing of Aquatic Bioresources
Catchability of the Sigsbee trawl for bivalve molluscs
Blinova D.Yu., Manushin I.E.
Abstract
Background. Bivalve molluscs are an important component of the benthic ecosystems of the Russian shelf seas; however, the assessment of quantitative characteristics of their sublittoral communities presents several challenges. Relevance. The calculated catchability coefficient plays a crucial role in evaluating the biomass and density of the molluscan communities during the stock assessment surveys. The aim of this work is to calculate the catchability coefficient of the Sigsbee trawl for three forms of bivalve molluscs: surface-dwelling, semi-burrowing (inhabiting the upper layers of the substrate), and deeply burrowing organisms. Methods. The calculations have been performed using the data from 291 trawl stations and 331 bottom grab stations (all samples were taken in five replicates), collected during the benthic survey of the Barents Sea in 2003–2008. Results. Based on a comparison of the occurrence of molluscs in the catches from the Van Veen bottom grab (quantitative fishing gear) and the Sigsbee trawl, three trawl catchability coefficients were obtained: 0.97 for surface-dwelling molluscs, 0.84 for semi-burrowing molluscs, and 0.64 for deeply burrowing molluscs. Conclusion. The obtained catchability coefficients can be used to calculate the density and biomass of bivalve communities during surveys conducted with the Sigsbee trawl.
Keywords: Barents Sea, Sigsbee trawl, catchability coefficient, bivalve molluscs
Informational Messages
Monitoring of hydrochemical and toxicological status of the Don River waters near stanitsa Romanovskaya (Rostov Region) in the late spring season of 2025
Kosenko Yu.V., Bragina T.M., Korablina I.V., Petrenko A.A.
Abstract
Background. The lower reaches of the Don River present the main habitat for the aquatic biological resources of the Southern Russia and play a crucial role in their reproduction. Through the ages, the current area of the Rostov Region supported active fisheries, including exploitation of sturgeons and other valuable fish species. Along with food security provision for the population, the Don River serves as an important source of potable and utility water. Relevance. Investigation of the water quality in the Don River as a living environment for aquatic biological resources presently remains relevant. The aim of this work is to analyse hydrochemical and toxicological parameters of the Don River water in the late spring season of 2025 near stanitsa Romanovskaya in the Rostov Region. This article initiates a series of publications presenting the results of ecological monitoring of the aquatic bioresource habitat in the lower reaches of the Don River. Methods. Collection of samples and identification of hydrochemical parameters have been conducted according to the standard research methods. Analysis for pollution with priority toxicants has been carried out in compliance with the methodological guidelines adopted at the federal level. Results. Content of dissolved oxygen in the water of the investigated area was 7.9 mg/dm3, concentrations of ammonium nitrogen and nitrite nitrogen were
0.085 and 0.029 mg/dm3, total dissolved solids were 470 mg/dm3, and the trophic level of the water (23 units) was indicative of the eutrophic status of the Don River near stanitsa Romanovskaya. Total content of petroleum products did not exceed the lower detection limits for the used methods of measurement. Anionic synthetic surface-active substances, organochlorine pesticides, and polychlorinated biphenils in the water and bottom sediments of the investigated area were not identified, and the content of iron, manganese, zinc, chromium, copper, lead, nickel, cadmium, mercury, and arsenic did not exceed MACs for the water bodies of fishery importance and was in line with the average long-term values. Conclusion. Results of this study indicate that the aquatic environment of the Don River near stanitsa Romanovskaya was favorable for aquatic living organisms.
Keywords: Don River, lower reaches, water, analysis, hydrochemical parameters, pollution, toxic
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