Recent Submissions

  • Водные биоресурсы и среда обитания. Том 4, вып. 4

    Bragina, T.M. (Azov-Black Sea Branch of the FSBSI “VNIRO” (“AZNIIRKH”)Rostov-on-Don, Russia, 2021)
    GIS technology in the investigation of morphometric characteristics of the wintering pits in the Upper Reach of the Tsimlyansk Reservoir has been applied. Amphipods of the marine farms in Sevastopol coastal waters (Black Sea) have been investigated. New data on finding of alien prawn Macrobrachium nipponense (Decapoda, Palaemonidae) in the Don River (Azov Sea Basin) have been presented. Ichthyoplankton of the Russian territorial waters and exclusive economic zone in the Black Sea has been studied. Parasite fauna of the common carp (Cyprinus carpio Linnaeus, 1758) juveniles in the growing ponds of the Azov and Black Sea Fishery Basin has been identified. Comparative analysis of fishing conditions for the Azov Sea anchovy in September–November, 2019 and 2020 has been made.
  • On the announcement of the III International Scientific and Practical Conference “Biological Diversity: Study, Conservation, Restoration, Rational Use”, held on September 13–18, 2022 (Kerch State Maritime Technological University, Kerch, Russia)

    Azov-Black Sea Branch of VNIRO (2021)
    ОСНОВНЫЕ ТЕМАТИЧЕСКИЕ НАПРАВЛЕНИЯ: 1. Фундаментальная биология. 2. Наземные экосистемы. 3. Водные экосистемы. 4. Экологическое воспитание и образование. 5. Биоразнообразие и благополучие населения.
  • Results of the comparative analysis of fishing conditions for the Azov Sea anchovy in September–November, 2019 and 2020

    Panov, B.N.; Smirnov, S.S.; Spiridonova, E.O.; Negoda, S.A.; Trusova, K.T. (2021)
    The data on the stock and abundance of the European anchovy, its age, length, and weight characteristics, and the information on its distribution in the sea before the start of its fishing season have been considered. Abiotic environmental conditions of anchovy autumn migration have been monitored using daily indicators of atmospheric transfers in the area, as well as temperature and sea surface level (altimetry) at various locations of the Kerch pre-strait zones of the Azov and Black Seas from September 20 to November 20. In October 2020, the Azov Sea anchovy was in a better physiological state than in 2019, even though its stock remained virtually the same. Its fishing in the Black Sea in 2019 started early, lasted long, and was low-efficient; in 2020, on the contrary, it was late, short, and productive. Favorable conditions for the start of anchovy fishing in the Azov Sea were created by the northwestern atmospheric transfers and southeastern surface currents in the pre-strait zone of the Azov Sea, and the northern atmospheric transfers and southern surface currents in the Kerch Strait were more favorable for the anchovy migration to the Black Sea. Anchovy fishing in the Azov Sea started at the sea surface temperature 17.0–17.5 °C, and its large-scale fishing in the Black Sea started at 16 °C. In the Kerch pre-strait zone of the Black Sea, the predominance of eastern geostrophic currents facilitates the migration of the Azov Sea anchovy to the Caucasian coast. The strengthening of these currents facilitates the anchovy migration and reduces the effectiveness of its fishing, and their weakening exerts an adverse impact on its migration but increases the effectiveness of its fishing.
  • Parasite fauna of the common carp (Cyprinus carpio Linnaeus, 1758) juveniles in the growing ponds of the Azov and Black Sea Fishery Basin

    Khorosheltseva, V.N.; Strizhakova, T.V.; Kerimova, A.A.; Denisova, T.V. (2021)
    Fish farms located in the Azov and Black Sea Basin contribute greatly to the development of the fisheries and aquaculture in the Russian Federation. Here, the main cultivation targets are carp species, especially common carp (Cyprinus carpio Linnaeus, 1758). This work is aimed at the updating of the data on the current composition of the parasite fauna of the common carp from the rearing ponds of the Azov and Black Sea Fishery Basin. At the early stages of post-embryonic development, carp juveniles are exposed to parasite infestation both with a direct life cycle (before their transition to exogenous feeding) and with a complex life cycle (upon feeding on zooplankton organisms and benthos). At the investigated fish farms, the range of parasites in the carp juveniles covered 16 species from 5 classes: Peritricha (Trichodina sp. Ehrenberg, 1830), Monogenea (Dactylogyrus extensus Mueller et Van Cleave, 1932, Dactylogyrus sp. Mueller et Van Cleave, 1932, Gyrodactylus sp. Mueller et Van Cleave, 1932), Trematoda (Diplostomum sp. met. Nordmann, 1832, Posthodiplostomum cuticola met. Nordmann, 1832, Tylodelphys clavata met. Nordmann, 1832), Nematoda (Nematoda sp. l. Rudolphi, 1808, Spiroxys contortus l. Rudolphi, 1819), Cestoda (Bothriocephalus acheilognathi Yamaguti, 1934, B. opsariichthydis Yamaguti, 1934, Khawia sinensis Hsü, 1935, Neogryporhynchus cheilancristrotus Wedl, 1855, Paradilepis scolecina Rudolphi, 1819) and Crustacea (Lernaea elegans Leigh-Sharpe, 1925, Ergasilus sieboldi Nordmann, 1832). A considerable share (31.25 %) of the total number of parasites detected was comprised of the representatives of Cestoda class, found in four farms out of five investigated. Infestation rates for most parasite species were low, except for the Asian tapeworm Bothriocephalus acheilognathi.
  • Ichthyoplankton of the Russian territorial waters and exclusive economic zone in the Black Sea

    Nadolinsky, V.P.; Patyuk, V.V.; Efanov, A.D. (2021)
    Survival rate of a generation at the embryonic and larval stages of the life cycle plays a crucial role in the formation of fish stocks. The data on the distribution of the fish individuals at the early stages of their development allow for the mitigation of anthropogenic negative impact on the stocks of aquatic living resources. This study has been aimed at the investigation of the species composition and abundance of thermophilic and psychrophilic fish species at the early stages of their development in the Russian territorial waters and exclusive economic zone in the Black Sea, as well as the assessment of their status in these areas. Sampling was conducted using a cone-shaped ichthyoplankton net with 80 cm diameter opening (IKS-80), off the board of the vessel going through the circling motion at 3 knot speed for 10 minutes. In the summer season, the major share of the individuals caught at their embryonic stages of development is comprised by the European anchovy, red mullet, Atlantic horse mackerel, and annular seabream eggs. Among early juveniles, the larvae of gobies, blennies, and pipefishes prevail. It has been found out that the highest diversity of the fish species at their early stages of development is recorded in the summer season: 58 species in the territorial waters, and 14 species in the exclusive economic zone. Winter ichthyoplankton is not very diverse—only 4 species have been recorded. In the territorial waters, littoral fish species at their early stages of development prevail. Ichthyoplankton catches in the exclusive economic zone are mostly comprised by pelagic zooplanktivorous and pelagic carnivorous species. In the winter ichthyoplankton catches, both in the territorial waters and in the exclusive economic zone, eggs and early juveniles of 4 fish species are recorded: European sprat (eggs and larvae), whiting (eggs and larvae), shore rockling (larvae), and sand lance (larvae). Low species diversity of the ichthyoplankton during the winter season results from the low number of winter-spawning species.
  • New data on finding of alien prawn Macrobrachium nipponense (Decapoda, Palaemonidae) in the Don River (Azov Sea Basin)

    Zhivoglyadova, L.A.; Nebesikhina, N.A.; Elfimova, N.S.; Afanasyev, D.F. (2021)
    For the first time, a freshwater prawn of the genus Macrobrachium Spence Bate, 1868, earlier unknown for the basin of the Azov Sea, was recorded in the lower reaches of the Don River in September, 2019. Based on their morphological characteristics, the found specimens were identified as M. nipponense (De Haan, 1849). This work presents the results of genetic analysis confirming the species status of the prawn, and also reports on new discovery and spreading of this species in the Don River. Oriental river prawn M. nipponense is a subtropical species, in its natural range widespread in Southeast Asia. Since the middle of the 1960s, this species is rapidly expanding its range in Eurasia. In a temperate climatic zone within the area of the former USSR, this thermophilic species was introduced in cooling ponds of thermal power plants (TPP). Acclimatization of M. nipponense was carried out as a part of warm-water aquaculture in order to improve the food supply of fish and enrich the fauna of TPP cooling ponds. This paper summarizes the available information about the formation of stable populations of M. nipponense within the area of the former USSR countries, as well as an assessment of the risks of invasion in the Don River.
  • Amphipods of the marine farms in Sevastopol coastal waters (Black Sea)

    Grintsov, V.A.; Shchurov, S.V. (2021)
    Amphipods are one of the main taxa of invertebrates inhabiting the structures of marine farms. On the collectors of oyster and mussel farms in the Black Sea, their density reaches more than 200,000 ind.·m2 of the projected surface of the substrate. Amphipods, being a valuable food source for a number of fish and invertebrate species, as well as a consumer of organic matter, can increase the productivity of the Black Sea coastal waters. This work is aimed at the evaluation of the qualitative and quantitative characteristics of amphipods, as well as their biodiversity on the collectors of marine farms. To assess the species composition, biodiversity, and density of amphipods, standard methods have been used; the density was calculated per m2 of the projected surface of the substrate, based on the geometry of the marine farm components. 17 species of amphipods have been identified on the marine farm components, the most abundant of them being Jassa marmorata Holmes, 1905, Stenothoe monoculoides (Montagu, 1813), and Microdeutopus gryllotalpa Costa, 1853. The total density of amphipods in one sample on the farm structures reached 211,919 ind.·m2 of the projected surface of the substrate. The components of marine farms can facilitate the increase in the biodiversity and improve the quantitative characteristics of amphipods, which would result in the growth of the productivity rates of the Black Sea coastal waters.
  • Assessment of overgrowth of the Chelbas group of the Azov Sea Limans with aquatic vegetation

    Bondarenko, L.G.; Kulba, S.N.; Petrashov, V.I.; Smirnov, S.S.; Matveeva, E.I.; Rudakova, N.A. (2021)
    The Chelbas Limans play crucial role in the reproduction of semi-anadromous fish species. The efficiency of their spawning is closely related to the overgrowth of spawning grounds, therefore, the study of aquatic vegetation in the limans is essential for fisheries. This study is aimed at the investigation of the area and intensity of overgrowth of the Chelbas Limans with aquatic vegetation using remote sensing and GIS technologies. The materials on the dynamics of overgrowth of the Azov Sea limans belonging to the Chelbas group are presented for the period 2016–2021. The assessment of the overgrowth of these water bodies was carried out using the Modified Normalized Difference Water Index (MNDWI) and the radiometric Normalized Difference Vegetation Index (NDVI), which were calculated from the multispectral images of the European Space Agency Sentinel-2 satellite. The data of satellite remote sensing have been compared with the data of botanical surveys and visual observations. The area of overgrowth with aquatic vegetation in the Kushchevaty Liman varied within the range from 15 to 93 %, in the Gorkiy Liman it ranged within 12–65 %, and in the Sladkiy Liman the overgrowth area did not exceed 1.7 %. A four-level classification of the overgrowth of the water bodies according to the NDVI is proposed: class 0 is from -1.0 to -0.1, class 1 is from -0.1 to 0.3, class 2 is from 0.3 to 0.5, and class 3 is from 0.5 to 1.0. Examination of the aquatic vegetation in the Chelbas Limans has shown the dependence of the area of overgrowth of these water bodies with macrophytes on the regime of freshwater and seawater influx to the limans.
  • Application of GIS technology in the investigation of morphometric characteristics of the wintering pits in the Upper Reach of the Tsimlyansk Reservoir

    Kochetkova, A.I.; Bryzgalina, E.S. (2021)
    The shallow waters of the Upper Reach are the most productive natural spawning grounds in the Tsimlyansk Reservoir. The hydrological regime of the Upper Reach is of a channel type, which results in a high flow rate and contributes to the formation of deep-water areas and shallow-water ones (riffles) along the channel. In turn, deep-water areas play a key role in the preservation of aquatic biological resources during the most unfavorable periods of the year. This work was aimed at the comprehensive morphological investigation of the wintering pits in the Upper Reach of the Tsimlyansk Reservoir in 2019, as well as at the analysis of the materials collected in its course. This article presents the data collected during the bathymetric survey of the wintering pits in the Upper Reach of the Tsimlyansk Reservoir; using GIS, the morphometric characteristics of seven wintering pits have been calculated, and three-dimensional models of the bottom relief of these wintering pits have been created. During this investigation, three new wintering pits — Kalachevskaya, Lipo-Lebedenovskaya, and a pit in the vicinity of khutor Peskovatka — have been identified. A comprehensive analysis of the collected data indicates that the most pronounced in terms of the bottom topography wintering pits are Kalachevskaya, Golubinskaya, Nabatovskaya, and Peskovatskaya.
  • Current state of the habitat of commercial invertebrates in the hypersaline lakes of Crimea

    Borovskaya, R.V.; Zhugaylo, S.S.; Pugach, M.N.; Adzhiumerov, E.N.; Krivoguz, D.O. (2020)
    Hydrological and hydrochemical conditions in the hypersaline water bodies of Eupatorian, Tarkhankut, Perekopsk, and Kerch groups of lakes were investigated. Fisheries value of these lakes lies in providing the habitat for such fishing targets as brine shrimps (Artemia) and chironomids. As the main source of primary empirical data, findings of the expeditions conducted in the spring, summer and autumn seasons of 2017–2019 have been used. As a result, it has been found out that, in general, abiotic environmental factors in the majority of the lakes in the spring – autumn season were adequate for development of the aquatic living organisms inhabiting them. It was supported by positive hyrdobiological developmental indices of these species and indicated their high adaptability to the existing state of their habitat, in particular, saline and oxygen regimens. However, the autumn season of 2017 was unfavorable for most of the lakes in terms of development of the aquatic living organisms. Substantial increase in salinity led to the depression of brine shrimp populations and to the death of chironomids. A fairly high content of mercury in some hypersaline water bodies located in the Western and Northern Crimea also comes under notice. In the case of Aygul Lake, it is associated with proximity of chemical enterprises; however, the sources of polluting substances in the other investigated water bodies at present remain unknown and require further investigation.
  • Hydrological and hydrochemical criteria for typification of the water bodies aimed for development of commercial aquaculture in the southern and south-eastern parts of the Rostov Region

    Barabashin, T.O.; Kosenko, Yu.V.; Zhukova, S.V.; Belousov, V.N.; Korablina, I.V. (2020)
    This paper presents materials on the development of criteria for the typification of water bodies for the purposes of commercial aquaculture on the example of model water bodies in the Rostov Region. Altogether, 24 water bodies located in the southern and south-eastern parts of the Region have been investigated. The development of criteria for the typification of water bodies has been carried out based on hydrological and hydrochemical indicators, which were scored in 4 blocks. The total score established for the main hydrological and hydrochemical parameters can be used as a criterion for a water body being suitable for the purposes of commercial aquaculture. The dependence of suitability of the water body for fish farming on its location, the average annual flow rate of rivers or the annual precipitation–evaporation ratio according to the established scores has not been revealed. However, in the zone of very arid climate, more unusable water bodies have been identified. Since, according to the conditions of water availability, almost all water bodies should be classified as the reservoirs that are insecure for fish farming, the number of water bodies not recommended or recommended with significant restrictions amounted to only 25 % of the total. This indicates a fairly high potential for fish farming even in the arid zone of the Rostov Region. A brief hydrological and hydrochemical characterization of each investigated water body can be used to develop scientifically grounded recommendations for the organization of fish farms for the purposes of commercial aquaculture.
  • Resolution of the 9th All-Russian Scientific Conference “Commercial Invertebrates”, 30 September – 2 October, 2020 (Kerch, Crimea, the Russian Federation)

    Azov-Black Sea Branch of VNIRO (2021)
    IX Всероссийская научная конференция «Промысловые беспозвоночные» впервые состоялась в г. Керчь и проходила с 30 сентября по 2 октября 2020 г. на базе ФГБНУ ВО «Керченский государственный морской технологический университет» (Кафедра водных биоресурсов и марикультуры) и Азово-Черноморского филиала ФГБНУ «ВНИРО» («АзНИИРХ»). В работе IX конференции непосредственное участие приняли лишь шестнадцать специалистов, — таким образом, прошедшая конференция оказалась еще более малочисленной по сравнению с предшествующей VIII конференцией и другими, ранее проходившими подобными встречами. Вероятной причиной этого является многолетнее сокращение штатов и финансирования рыбохозяйственных НИИ и учебных заведений, а также эпидемиологические ограничения на передвижение. Доклады на конференцию направили 14 научно-исследовательских и образовательных учреждений. Изданный сборник содержит 24 доклада 43 авторов, из них 12 были доложены авторами. Среди регионов страны по количеству сообщений лидировали хозяева конференции: Азово-Черноморский бассейн (10 статей и докладов, том числе заболевания моллюсков — 3 доклада, аквакультура — 2, гастроподы — 2, жаброноги, двухстворчатые моллюски, культивирование зоопланктона — по одному). От Северного бассейна, включая море Лаптевых, поступило 7 докладов (крабы и крабоиды — 4, креветки — 2, двустворчатые моллюски — 1), от Дальневосточного бассейна — 5 докладов (крабоиды — 2, двустворчатые моллюски, гастроподы, иглокожие и мизиды — по одному, соответственно), по Южному океану было 5 докладов (криль — 4, крабоиды — 1). В целом следует подчеркнуть, что постоянно снижающееся число участников этой важной конференции входит в явное противоречие с сосредоточением отечественного вылова промысловых беспозвоночных в водах России и постоянным, начиная с 2008 г., ростом их вылова, который к 2018 г. удвоился и имеет высокую тенденцию к дальнейшему росту. Быстро набирает объемы культивирование промысловых беспозвоночных, прежде всего за счет моллюсков – устриц и мидий.
  • Possible consequences of increasing the commercial size of red mullet in the Azov and Black Sea Fishery Basin up to 10 cm

    Shlyakhov, V.A. (2021)
    The current practice of regulation and management of red mullet Mullus barbatus L. fishery in the Black and Azov Seas has been considered. The data on catch composition and Russian fishing intensity in 2016–2020 are presented, as well as the data on some specific features of regulating measures — in particular, regarding limitation of by-catch of the fish that has yet to reach its commercial size. Analysis of seasonal distribution of the annual catches and actual by-catch of off-sized red mullet in the Black and Azov Seas has been conducted. Based on the analysis results, possible consequences of the adoption of the new commercial size, proposed for red mullet and its fishery by the Association of Aquatic Biological Resources Providers “Fishermen of Crimea” at the meeting of the Azov-Black Sea Basin Scientific and Fishing Council (July, 2020, Rostov-on-Don), have been considered. Mathematical modelling has shown that, in the fifth year after a speculative adoption of the red mullet commercial size as 10.0 cm in 2019, the growth of SSB (spawning stock biomass) of red mullet would be 2.4–2.7 %. Low effect of the adoption of a new commercial size could be explained by a prospective preservation of insignificant amount of nonmature fish from being targeted, which could not exert a considerable impact on the formation of red mullet stock and its dynamics.
  • Fishery and biological data and restrictions of shrimp harvesting in the Black and Azov Seas

    Saenko, E.M.; Dudkin, S.I.; Marushko, E.A.; Kostenko, T.V. (2021)
    This work indicates increasing fishing pressure on the shrimp populations in the Azov and Black Seas and analyzes possible negative impact of the shrimp harvesting on juvenile fish. An assessment of shrimp harvesting as it relates to sustainable fishing, harvesting and preservation of aquatic biological resources has been performed. The catches of shrimp and by-catches of other aquatic species with various shrimp harvesting gear in different areas of the Black Sea have been analyzed. The obtained fishery and biological data made it possible to elaborate the timeframe for the spawning-related ban on shrimp commercial harvesting and to recommend setting it on May 1 – July 14, as well as to propose increasing the minimum mesh size in the netting of shrimp harvesting gear from 6 to 8 mm and to show the prospects of harvesting gears with 10 mm mesh size. The data obtained have also been instrumental in revision of the time of the daily ban on the use of shrimp fyke nets in the Black Sea, which shifted their removal from the water body from 8 to 10 a.m. Revision of the restrictions on shrimp harvesting was carried out in terms of elaboration of the fishing rules for the Azov and Black Sea Fishery Basin.
  • Dynamics of the industrial fishing indices of the European anchovy in the Azov and Black Sea Basin in recent years

    Stafikopulo, A.M.; Negoda, S.A. (2021)
    This paper considers the key aspects of the anchovy industrial fishing in the Azov and Black Sea Basin in 2015–2020. The factors, determining parameters and indices of anchovy fishing, have been analyzed; they include technical specifications and performance characteristics of the vessels engaged in fishing activity, time expenditures for fishing operations, catches per unit effort, fishing areas, the state of fish stocks, and other characteristics. Daily vessel activity reports on the European anchovy fishing for the indicated time range have been processed; the obtained data made it possible to infer the dynamics and trends of industrial fishing indices for the Azov and Black Sea stocks of the European anchovy for this period. The indices of the European anchovy industrial fishing by the Russian Federation in 2015– 2020 have been summarized, both in general and by areas of the Caucasian and Crimean Black Sea coast. The factors, which have predicated the changes in anchovy yield and fishing pressure on the Azov population of the European anchovy, have been investigated. The influxes and the presence of the European anchovy from the Black Sea stock in catches extracted near the Caucasian shore have been recorded, and its fishing operations near the Crimean shore have been characterized. The presented data give evidence that the existing approach of geographical division of the European anchovy into the “Black Sea” and the “Azov Sea” stock units, which is currently laid down the line going through Cape Sarych, does not correspond to the actual distribution of the Black Sea anchovy stock and leads to misrepresentation of fishing statistics. Some means of regulating anchovy industrial fishing and fishing pressure are presented.
  • Specific features of maturation of Russian sturgeon (Acipenser gueldenstaedtii Brandt, 1883) females in the environment of Temryuk and Grivenskoe sturgeon hatcheries

    Vorobieva, O.A.; Gorbenko, E.V.; Panchenko, M.G.; Pavlyuk, A.A. (2021)
    The main source of recruitment to the population stocks of sturgeon fish species are broodstocks developed at sturgeon hatcheries in the early 2000s. This paper presents the materials concerning spawning intervals for repeat maturity of the females from the broodstocks in the environment of a sturgeon hatchery. This study was carried out at Temryuk and Grivenskoe sturgeon hatcheries in the Azov Sea and Kuban River Region from 2009 to 2020. The Russian sturgeon females upon their first and repeat maturity, aged 9–18, have been the subject of this study. Following this investigation, it has been found out that, in controlled environment of a sturgeon hatchery, the first maturity of A. gueldenstaedtii females occurs at the age of 11–13 (of 10 in isolated cases). Repeat maturity (the second and subsequent ones) has been observed two years after the previous spawning; a 3–4-year spawning interval is recorded in 25.0 % of the Russian sturgeon females. It has been established that in the case of repeat maturity, females show increased fecundity, oocyte size, yield of 1-day larvae per 1 individual, and viability of the offsprings, as compared to reproductive capacity of the females upon their first spawning. Results of the investigation of production characteristics of the breeders are of great scientific and practical interest.
  • Results of three-year rearing of so-iuy mullet Lisa haematocheilus (Temminck & Schlegel, 1845) = Mugil soiuy (Basilewsky, 1855), obtained by artificial reproduction and fed on natural feeds, in the model reservoir

    Turkulova, V.N.; Novoselova, N.V.; Zaichenko, E.A. (2021)
    The data on which this article is based have been collected during the investigation of so-iuy mullet (a valuable fishing target showing promise for pond and grazing aquaculture) reared from eggs to three-yearlings. This study was conducted in the research facility “Zavetnoe” on the coast of the Kerch Strait in 2018–2020. The data on growth and survival rates of so-iuy mullet during a three-year rearing cycle in the model reservoir have been presented. It is shown that the main hydrochemical and hydrobiological parameters of the water during so-iuy mullet rearing were favorable. The thermal profi le of the aquatic environment ranged from 3.5 to 26.0 °С, NaCl salinity varied from 18.0 to 21.0 ‰, and the oxygen content ranged within 5.33–10.23 mg/L. In the course of this study, the feed reserve of the model pond was at the level of a mesotrophic water body; the average biomass of the zooplankton was 2.12 g/m3, while the average biomass of the fodder zoobenthos equaled 8.37 g/m2. The data on the number of taxonomic groups of the organisms in the so-iuy mullet digestive tract, recorded for different age classes, are presented. It has been found out that, starting from the fingerlings with 1 g weight and for the entire three-year period of this investigation, the average daily weight gain of the so-iuy mullet was 0.47 g/day, with the average daily length gain 0.05 cm/day. The absolute weight and length gains of the so-iuy mullet three-yearlings in the model reservoir were 364.17 g and 35.37 cm, respectively. Survival rate of the so-iuy mullet out of the initial number of yearlings reached 8 %; for two-yearlings it made up 1.1 %, and 0.54 % for three-yearlings. This study will make it possible to assess the actual stocking efficiency and yield potential of the so-iuy mullet juveniles (1–2 g initial weight) from culture, released into the natural habitat.
  • Hydrometeorological conditions of the Kerch Bay in 2017–2019

    Kochergin, A.T.; Borovskaya, R.V. (2020)
    Based on the data from weekly hydrometeorological observations, conducted in the Kerch Bay in 2017–2019, comparative analysis of variability in average monthly values of surface air and water temperatures, wind activity and wave action, water transparency, and salinity of the upper water layer with those recorded in 2007–2009 has been conducted; these two time ranges have been also compared with similar conditions of the second half of the 20th century and the beginning of the 21st century. During the recent decade, a trend of the increase in the amount of hot summer days and the decrease of freezing winter ones was recorded, as well as the raise of water salinity by a significant measure, from 10.7–12.8 to 14.5–17.6 ‰, resulting from the reduction of freshwater river flow into the Azov Sea and increased evaporation due to higher water temperature. Prevailing negative anomalies of wind speed were observed, as well as the change of the negative trend in the first time range to the positive trend in the second one. Due to the limited fetch distance, average monthly wave height in the bay over the course of entire 2017–2019 observations did not exceed 0.9 m. Correspondence between positive trends of wave height and wind speed was recorded. During the same period, the annual maximum of transparency coincided with the summer season, whereas the annual minimum fell on different months of the other seasons.
  • The first finding of the oriental river prawn Macrobrachium nipponense (De Haan, 1849) in the Lower Don River (Azov Sea Basin)

    Zhivoglyadova, L.A.; Vekhov, D.A.; Spiridonov, V.A.; Guskova, O.S.; Afanasyev, D.F. (2021)
    In September 2019, in the lower reaches of the Don River, two specimens of a shrimp previously unknown for this river basin were recorded. The finding was made downstream of khutor Arpachin. The coordinates of the first finding location are as follows: N 47.258610°, E 40.166330°. The shape and armature of the rostrum, the proportions of the second pereopods, and a number of other morphological characteristics allowed the species to be identified as Macrobrachium nipponense (De Haan, 1849) (Decapoda, Crustacea, Palaemonidae). M. nipponense (De Haan, 1849), or oriental river prawn, is a subtropical shrimp, originated and widely distributed in Southeast Asia, including Japan, China, Republic of Korea, Vietnam, Myanmar and Taiwan. It is known that in the 1980–1990s in the temperate zones, this species was introduced into the cooling ponds of thermal power stations as a target of warm-water aquaculture. Several decades later, M. nipponense began to be observed outside the primary recipient reservoirs. The first findings of this genus were considered to be associated with long-distance migrations of this prawn. However, more recent data have shown that, at least in the south of the temperate zone, the prawns have formed stable populations outside warm water refugia. Finding of the oriental prawn in the Don River not only expands the known range of the species but also gives evidence for the continuation of the process of active expansion of M. nipponense through Eurasian water bodies.
  • Characterization of oil pollution of the Azov Sea in 2016–2020

    Korablina, I.V.; Pavlenko, L.F.; Klimenko, T.L.; Anokhina, N.S.; Ekilik, V.S.; Savchuk, I.A.; Ryzhkova, V.V. (2021)
    This article presents the results of oil pollution monitoring of water and bottom sediments of the Azov Sea in the summer and autumn seasons of 2016–2020. The detected concentrations of petroleum products are given in terms of the total content of the main petroleum components: hydrocarbons, resins, and asphaltenes. In some water samples, the concentrations of petroleum products varied from <0.02 to 2.0 mg/dm3 in summer, and from <0.02 to 0.20 mg/dm3 in autumn. In various years, the weighted average concentrations of petroleum products in water exceeded the maximum permissible level (0.05 mg/dm3) by 0.08–2.6 times in summer, and by 0.08–1.2 times in autumn. In sediments, the concentrations of petroleum products were in the range of <0.02–1.01 g/kg in summer, and 0.02–0.85 g/kg dry weight in autumn; the weighted average concentrations varied from 0.19 to 0.55 mg/dm3 and from 0.25 to 0.34 mg/dm3 during the summer and autumn seasons, respectively. More than a half of the investigated sea bottom sediments belong to the category of pollution indicated by a decrease in species diversity and the replacement of dominant forms. According to the data averaged over the period under study, higher pollution of water and bottom sediments is observed in the central regions of the Taganrog Bay and the sea. The most significant inflow of petroleum products occurs in the eastern regions of the Taganrog Bay and the sea in autumn, and in the southern region of the sea in summer.

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