Volume 5. Number 1

 

Vertical distribution of biogenic elements in Gelendzhik area in 2019    
P. A. Borodulina, V. K. Chasovnikov, A. V. Fedorov
Abstract. Investigation of the vertical distribution of nutrients is an important component in studying the entire ecosystem of the Black Sea. Biogenic elements play a crucial role in the primary production in the sea coastal zone and are among the main indicators of the ecological state of marine waters. Any changes in nutrient regime are reflected in biological marine plankton communities. This work was aimed at the investigation of the seasonal vertical dynamics of biogenic elements in the northeastern part of the Black Sea near the city of Gelendzhik in 2019. To determine concentration of nutrients, the methods standard to the practice of marine hydrochemical studies have been used. As a result of this investigation, it has been found that nitrate and ammonium forms of nitrogen, and mineral phosphorus have well-defined concentration maxima that correspond to certain values of conditional density. There is one deep maximum in the vertical distribution of nitrates; on average, the concentration of nitrate nitrogen is 5.57 μmol/L. Vertical profile of phosphates has an upper  maximum (average concentration of 1.39 μmol/L), a minimum (1.19  μmol/L) and a lower maximum (6.64 μmol/L) of concentrations. Seasonal changes in climatic conditions, coastal runoff and   rate of phytoplankton   consumption determine the dynamics of nutrient concentrations in the photic layer of marine waters.
Keywords: biogenic elements, Black Sea, nitrate nitrogen, nitrite nitrogen, ammonium nitrogen, mineral phosphorus, silicon

Hydrochemical criteria for typification of the Azov limans of the Krasnodar Territory as the spawning grounds for semi-anadromous fish species    
Yu. V. Kosenko, T. O. Barabashin, E. A. Shevtsova, E. A. Poroshina, V. N. Belousov, T. B. Kartamysheva, A. I. Glubokov
Abstract. The Azov limans of the Krasnodar Territory are of major fishery importance, as they serve as the spawning grounds for valuable semi-anadromous fish species. Roach and zander at their early stages of development are highly susceptible to the negative effects of various abiotic environmental factors, which makes them very dependent on the hydrochemical status of the water bodies during the spawning season. As the hydrochemical   regime, in turn, closely depends on the   hydrological regime   and the   overgrowth area of the limans, it can be used as a criterion parameter that affects the success of spawning of the semi- anadromous fish species and growth of their juveniles. This paper proposes a system of hydrochemical scoring and establishes the criteria for the typification of the limans based on their suitability for spawning and growing of zander and roach following the data collected in the spring season of 2017–2021. Based on the analysis of the hydrochemical data, 3 main blocks for the typification of limans according to their suitability for spawning of semi-anadromous fish species were identified: gas conditions, ionic composition and the content of biogenic components in water along with an assessment of the primary production of phytoplankton. It has been found out that the Azov limans of the Krasnodar Territory vary significantly in terms of the hydrochemical composition of their water. Some limans are characterized by pronounced fluctuations of the hydrochemical and ichthyological characteristics in interannual dynamics. Based on the hydrochemical criteria, the limans of the Kulikov-Ordynsk group (Bolshoy Bashtovy, Donchikov, Bolshoy Grushchany) and the Kulikovskiy Liman were the most favorable for the spawning of zander and roach, and the Ryasnoy, Boykievskiy and Kurchanskiy Limans were the least favorable. The low production coefficient in the water of most limans can be indicative of their high degree of overgrowth with macrophytes, which control is crucial in increasing the efficiency of natural reproduction of semi-anadromous fish species. The correlation between the criterion scoring of the limans based on the hydrochemical regime and the density of distribution of zander and roach juveniles has been established, which confirms the validity of this study.
Keywords: Azov limans, hydrochemical regime, typification criteria, limiting factors, reproduction, semi-anadromous fish species

Use of the thermohaline method for determining the quasi-heterogeneity of the water masses in the Azov Sea    
V. M. Shishkin, S. V. Zhukova, V. G. Karmanov, L. A. Lutynskaya, D. S. Burlachko, T. I. Podmareva, E. A. Taradina
Abstract. This paper considers the possibility of applying the thermohaline method (using the construction of T,S-diagrams) to determine the quasi-heterogeneity of water layers in the Azov Sea drawing on the expedition data obtained in 2016–2020. The diagrams allowing to identify   a two-layer   water structure in the aquatic environment of the Azov Sea (excluding the   area   of Taganrog Bay) have   been constructed. The analysis of water stratification in the conditions close to the natural regime of the sea (thus, including salinity), as well as in the present conditions of its salinization, has been carried out. The data obtained through the analysis of sample observations have been verified with mathematical methods; the explanations from the standpoint of T,S-analysis of the aquatic environment have been presented. The hydrological features of the salt regime of the Azov Sea are given with the specification of the situations during the advection of the Black Sea waters, which precondition a stable separation of the waters in the southern part of the sea into surface and bottom “water masses”. These possibilities are justified mathematically, and for the modern period of considerable salinization of the sea, in accordance with the theory of T,S-analysis of water masses, a classification assessment of the aquatic environment is proposed.
Keywords: temperature, salinity, conditional density, aquatic environment, water mass, structure, water stability

Age composition and linear growth of the invasive ark clam species (Anadara kagoshimensis (Tokunaga, 1906)) in the Kerch Strait   
A. M. Zhavoronkova, N. A. Sytnik, A. P. Zolotnitsky
Abstract. Age composition and linear growth rate in the ark clam (Anadara kagoshimensis) population in the Kerch Strait are investigated. Based on the analysis of seasonal annual growth rings and chevron grooves on the hinge ligament of the ark clam, the age of this species has been examined, which, in this population, was found to be  7 years (6+). Based on the age and annual length gain of the  molluscs in the course of their ontogenesis, a theoretical growth curve is presented; it has been calculated following the von Bertalanffy growth  equation:  are the parameters equaling to 50.2, 0.428, and 0.022, respectively. The highest growth rate was observed in the first year of life, 17 mm; however, later on, it was consistently decreasing and did not exceed 2 mm/year in the oldest individuals. The relationship between the ark clam’s growth rate  (PL) and its length, approximated by the inverse linear function  , is presented. Based on the parameters of the von Bertalanffy growth equation, a theoretical maximum age of the investigated species has been calculated; it was found to be 8.74 years. It has been shown that the linear growth rate of the ark clam in various areas of the Azov and Black Sea Basin is determined by the water salinity to a considerable extent, because in the desalinated areas (Azov Sea, Kerch Strait, Danube River Delta and Northwestern Black Sea with 10–14 ‰ salinity), the growth rate of this mollusc was 1.5–2 times lower than in the Southeastern Black Sea (18 ‰).
Keywords: Kerch Strait, Anadara kagoshimensis, annual growth rings, age, chevron grooves, growth rate, von Bertalanffy growth equation, salinity

Effect of different doses of pituitary hormone on the reproductive performance of shemaya females (Alburnus leobergi, Freyhof & Kottelat, 2007)
G. V. Golovko
Abstract. The stage of obtaining high-quality gonads was explored in the course of development of the biotechnology for artificial reproduction of the anadromous Azov-Black Sea shemaya Alburnus leobergi (Freyhof & Kottelat, 2007), a valuable species   of the Azov Sea   ichthyofauna. This research is aimed at the assessment of the maturity status of shemaya females and males after their wintering in the ponds of a fish farm on the Lower Don at a thermal constant of 849 degree days (DD) and at the evaluation of the reproductive parameters of shemaya females exposed to different doses of the pituitary extract. In all literary sources available, the information on this topic has been scarce and fragmentary, and in the foreign sources, it was entirely absent. Our investigation has shown that the gonads of 55 % of males were at 5th and 5th–6th stages of maturity. At the same time, females significantly differed by the degree of gonad maturity: 26.0 % of females had first-generation eggs at different stages of resorption, the sexual products of
15.8 % of females were at the 5th stage of maturity, and 58.2 % of females had immature sexual products at the 3rd–4th and 4th stages of maturity. The investigation of the effect of two doses (6.0 and 9.0 mg/kg) of the pituitary gland extract with application of the fractional method showed that 15.0 % and 16.7 % of injected shemaya females with the most mature eggs responded to the preliminary dose of the pituitary extract by ovulation of physiologically sound eggs (0.6 and 0.9 mg/kg, respectively). 20.0 % and 6.7 % of females responded to the provoking dose of pituitary hormone   by ovulating physiologically high-quality eggs in accordance with the concentration applied. The fertilization rate of physiologically sound eggs in both scenarios had similar values (97.4 and 97.9 %). Since the thermal constant of 849 DD is excessive for the start of artificial reproduction of the Azov-Black Sea shemaya, it is necessary to conduct research in order to identify the thermal constant precluding the loss of the first-generation eggs caused by the incipient processes of resorption.
Keywords: Azov-Black Sea shemaya Alburnus leobergi, hormonal stimulation, maturity stage of sexual products, gonadosomatic index (GSI), generations of oocytes, thermal constant

Heavy metals and arsenic in water, bottom sediments and Black Sea turbot (Scophthalmus maeoticus, Pall., 1814) in the Caucasian Shelf area in the Black Sea (1995–2020)    
I.V. Korablina, Zh. V. Gevorkyan, L. G. Gorgola, T. O. Barabashin
Abstract. The results of investigation of the pollution of the water and bottom sediments of the Caucasian Shelf in the Black Sea by heavy metals (copper, zinc, lead, cadmium, mercury) and arsenic, as well as their content in the Black Sea turbot   Scophthalmus maeoticus (Pallas,   1814) are presented for   1995–2020. In the water and turbot, the determination of Zn, Cu, Pb, As, and Cd has been conducted using the method of atomic absorption with electrothermal atomization; mercury in all components of the ecosystems was measured using the method of atomic absorption with “cold steam”; in the bottom sediments, the content of Zn, Cu, Pb and As was identified using X-ray fluorescence method. In 1995–2020, in some water samples, the concentrations of zinc, copper and mercury exceeded the maximum   permissible level   established   for the water bodies of fisheries importance, while the lead and cadmium were below it. The arsenic content during the entire observation period was extremely low. A noticeable decrease   in   the concentrations of zinc, lead and copper in the shelf waters of the Black Sea in the present period as compared with the years of the greatest pollution (1995–2002) was recorded. In the bottom sediments, the content of lead, zinc and mercury exceeded their content in the earth's crust for several years; for arsenic, the excess was recorded throughout the entire observation period. This mostly results from the peculiarities of the granulometric composition of the shelf bottom and, to a much lesser extent, from anthropogenic influence. The differences in the bioaccumulation of heavy metals and arsenic in the organs of the Black Sea turbot are shown. Out of the identified elements, only lead, mercury and arsenic in isolated cases exceeded the permissible level in the organs of the turbot in some years.
Keywords: Black Sea, pollution, turbot, heavy metals, arsenic, accumulation

Exotic fish species off the Black Sea coast of the Krasnodar Territory   
V. P. Nadolinskiy
Abstract. Each species strives to expand its range and spreads in all directions. Its expansion occurs in the direction where biological and abiotic factors are similar to its native habitat. Entering the area with different conditions activates the mechanism of adaptation to new conditions. If such an adaptation is successful, the range of this species expands in this direction, otherwise this area remains unclaimed. Possible migration routes of exotic species run along the coast of Turkey through the coast of the Republic of Georgia or along the coasts of Bulgaria, Romania and the Crimean Peninsula. Taking into account the existing system of currents in the sea, the most likely option seems to be their invasion into the Russian sector of the Black Sea as a result of migration from the Sea of Marmara through the Bosphorus Strait and further along the direction of the Anatolian and Caucasian currents. Another way is with ballast water. In 1995–2014, 7 monitoring stations under the authority of AzNIIRKH operated near the Black Sea coast of the Krasnodar Territory on a year-round basis. They were equipped with all the necessary types of fishing gear (set nets with a mesh size from 25 to 200 mm, bottom set nets with a minimum mesh size of 6.5 and 10 mm, cast nets with 30 mm mesh, etc.). AzNIIRKH-trained observers were present at each haul of the fishing gear and conducted the necessary catch analyses. All unusual species were preserved by freezing or taxidermy and transferred to the institute. As a result of the operation of AzNIIRKH monitoring stations, in the catches of commercial fishing gear off the Black Sea coast of the Krasnodar Territory in 2005 and 2012, two exotic species have been recorded: Siganus luridus (Rüppell, 1828) and Lophius piscatorius Linnaeus, 1758.
Keywords: range, exotic species, mediterraneanization, Mediterranean Sea, Aegean Sea, Black Sea, Siganus luridus, Lophius piscatorius

Problems of using riverbed ponds in aquaculture (in the context of recent legislative changes) 
S. A. Sennikov
Abstract. For a long time in the field of   aquaculture existed the uncertainty, associated   with the use of the ponds formed by water-retaining structures on watercourses (the so-called “riverbed ponds”), despite numerous attempts to resolve emerging contradictions legislatively—including another such   attempt   made last year by the adoption of Federal Law No. 163-FZ of June 11, 2021 “On the amendment of the Federal Law “On aquaculture (fish farming) and amendment of some legislative acts of the Russian Federation” and some legislative acts of Russian Federation”. The amendments introduced by this law establish new legal mechanisms for the use of riverbed ponds for the purposes of pond aquaculture, which makes their study particularly relevant. However, it will not be possible to fully understand the essence of these legislative changes without understanding the history and development of the legal framework applicable   to these water bodies. In this regard, this article shows how riverbed ponds through numerous legislative changes were gradually introduced into the property circulation and how the principle of separation of the water resources of riverbed ponds and the land under them appeared, which means that the water in such ponds remains federal, but the land under them may be in other forms of ownership. This article also discusses the questions of the correlation of this principle with other principles of the legal regulation underlying water and land legislation, and how it is perceived by judicial practice. The author analyzed in detail the amendments, adopted by Federal Law of 11.06.2021 No. 163-FZ, concerning the regulation of riverbed ponds, proposed a classification of the legal basis for the use of water bodies in fish farming, and concluded what problems in the use of riverbed ponds remained, despite recent legislation attempts to eliminate them. Finally, this article suggests directions for further changes, according to which, as it seems to the author, the legislator could go to solve the identified problems.
Keywords: ponds and water-filled quarries, riverbed ponds, fish farming, pond aquaculture, agreement on the use of a fish-breeding site, water use agreement, decision on the provision of a water body for use, water fund lands, agricultural lands, the principle of unity of the fate of a land plot and strongly related objects