Environmental Concerns and the State of Aquatic Environment
E. N. Bakaeva, M. N. Taradayko
Abstract. 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.
Keywords: freshwater pollution, biotic indices, macrozoobenthos, small rivers, coal-mining area, Eastern Donbass
I. V. Korablina, L. F. Pavlenko, T. L. Klimenko, N. S. Anokhina, V. S. Ekilik, I. A. Savchuk, V. V. Ryzhkova Abstract. 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 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.
Keywords: Azov Sea, water quality, bottom sediments, oil pollution
Biology and Ecology of Aquatic Organisms
L. A. Zhivoglyadova, D. А. Vekhov1, V. А. Spiridonov , О. S. Guskova, D. F. Afanasyev
Abstract. 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.
Keywords: Don River, Palaemonidae, Macrobrachium nipponense, invasive species, benthic communities
Aquaculture and Methods of Artiﬁcial Reproduction
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
V. N. Turkulova, N. V. Novoselova, E. A. Zaichenko
Fisheries and Processing of Aquatic Bioresources
A. M. Staﬁkopulo, S. A. Negoda
Abstract. 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.
Keywords: Azov and Black Sea Fishery Basin, fishing fleet, industrial fishing, types of vessels, European anchovy, fishing parameters, fishing effort, fishing pressure
E. M. Saenko, S. I. Dudkin, E. A. Marushko, T. V. Kostenko
Abstract. 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.
Keywords: Palaemon adspersus, Palaemon elegans, fishing, harvesting, fishing restrictions, season regulations, Azov Sea, Black Sea
V. A. Shlyakhov
Abstract. 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 non- mature fish from being targeted, which could not exert a considerable impact on the formation of red mullet stock and its dynamics.
Keywords: Mullus barbatus, Black Sea, Azov Sea, commercial size, fish catch statistics, catch composition, stock, recruitment, mathematical modelling