• Assessment of water quality in small rivers of the Seversky Donets and the Tuzlov River Basins using biotic indices

      Bakaeva, E.N.; Taradayko, M.N. (2021)
      The restructuring of the coal mining industry, which began in the 1990s, has impacted the environmental situation in Eastern Donbass within Rostov Region rather adversely. Aquatic ecosystems of rivers with low water content and, consequently, low dilution capacity are characterized by high susceptibility to anthropogenic impact. Samples of macrozoobenthos were taken in the areas with different anthropogenic load in 18 sections of small rivers of the Seversky Donets and Tuzlov River Basins: the upper reaches, the places downstream of mine drainage water outlets, and mouths. Based on a comparison of the values of the Woodiwiss, Parele, Goodnight–Whitley, and Mayer biotic indices, sections with different levels of water pollution have been identified in these three areas. Water was characterized as “clean” in 47 % of the sections according to the Goodnight–Whitley index, and in 27 % according to the Parele index. The greatest overlap in the estimation of water pollution level according to these indices was in the “polluted” category. Altogether 62 % of the river mouth waters, 50 % of the sections located downstream of mine drainage water outlets, and 17 % of the upper reaches are attributed to this level of pollution. According to all water indices, most of the sections are classified as “polluted”, although there is a difference. Thus, 94 % of the sections were “polluted” according to the Mayer index, 89 % of them according to the Woodiwiss index, 47 % according to the Parele index, and only 33 % of the sections were identified as “polluted” according to the Goodnight–Whitley index. The discrepancy in estimation of water pollution by biotic indices has been found in five cases out of eighteen investigated stations. The final score has been assigned according to the index with the most negative result. For Eastern Donbass area, taking into consideration the class of small rivers, their zoological and geographical characteristics, the consequences of restructuring the coal mining industry, and agricultural nature of this region, biotic indices should be considered as indicators of organic water pollution along with the abundance, biomass, and number of the macrozoobenthos taxa.
    • 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.
    • 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.
    • 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.
    • 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.
    • 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.
    • 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.
    • 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.
    • 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.