Sea Of Azov Research Articles

Менеджмент функціональної стабільності глобальної морської торгівлі

Management of the functional stability of global maritime trade is defined as a complex of strategic, organizational and logistical actions aimed at ensuring the efficient and uninterrupted functioning of international maritime services. different transport systems. Ukraine, which can become a key point in the transit of goods through the Black and Azov Seas, is of strategic interest in the thorough management of these processes. One of the main warehouse objectives is the development and promotion of effective risk management strategies. With the attention of the great economic, political and natural minds, it is necessary to recognize the possible risks that could arise in the global maritime trade. On-going systems for monitoring and responding to potential threats make it possible to anticipate a crisis situation and minimize its consequences.

Особенности современного строения подводной аккумулятивной формы банка Еленина

The Elenina Bank is an underwater accumulative form of the eastern part of the Sea of Azov. It was formed 2.5-1.7 thousand years ago during the Phanagorian regression. During the subsequent sea level rise the Elenina Bank was under water. The analysis of the modern structure of the Elenina Bank was carried out using literary sources and remote sensing data. Digital models of the underwater relief for the Elenina Bank were built on the basis of Sentinel-2 satellite images using the method of mutual correlation of the brightness of the spectrum channels and depth. The length of the Elenina Bank is about 40 km, the width is up to 5 km, the minimum depth of the water area is 1.5-2 m. Arc-shaped ridges up to 6 km long were found at the western tip of the bank. Currently, the Elenina Bank is active accumulative form and influences the lithodynamic regime of the adjacent part of the Sea of Azov. The transverse profile of the bank indicates the predominant direction of sediment movement – from S to N. The Elenina Bank accumulates most of the sediments transferred to the S-SE, but there is practically no extension of the edge of the accumulative body to the North due to a sharp drop in depths. The presence of the accumulative body of the Elenina Bank contributes to the formation of strong and stable currents to the North of it.

Study of the state of phytoplankton in the waters of the Sea of Azov in the late autumn period of 2021

The article presents the results of hydrobiological monitoring of the water area of the Sea of Azov in the late autumn period of 2021. The characteristics of the taxonomic composition and quantitative indicators of phytoplankton are given, the distribution of hydrobionts by dominant species is shown, and community structure and spatial distribution are determined

Genetic types of mud volcanism in the Cydonia and Acidalia regions of Mars

Small cone/mound-shaped structures are widespread on the northern plains of Mars. They are usually interpreted as mud volcanoes because of their close morphological resemblance to mud volcanoes on Earth (for example, in Azerbaijan and near the Sea of Azov). If this interpretation is correct, the small cones/mounds could be evidence of the existence of an extensive subsurface mud source, which, in turn, could be formed by the bottom sediments of a large water reservoir (ocean) that existed on the northern plains of Mars in the past eras of this planet’s geological history. Compared to mud volcanoes on Earth, the morphology of small cones/mounds on Mars varies over a wider range and, which may be due to a greater variety of mechanisms of formation of Martian cones/ mounds. In this study, we studied the morphology of small hills in the Cydonia and eastern Acidalia regions, which are located near the dichotomous boundary within the northern plains of Mars and found that there are 5types of cones/mounds, whose morphology probably characterizes the water-mud reservoir features.

The Late Cretaceous marine basin of platform Ukraine (morphometry, stages of development, lithology and stratigraphy of sedimentary formations)

Formulation of the problem. The relevance of the research is related to the formation of a holistic view of the Late Cretaceous Sea basin of the study area: its boundaries, area, the existence of probable land areas, conditions of sediment accumulation and historical development. The purpose of the article. Based on the results of exploratory, structural-exploratory and parametric drilling conducted during the State Geological Survey on scales of 1:50,000, 1:100,000 and 1:200,000 and own field research, we supplemented the information on the geohistorical chronicle of the Late Cretaceous of the southwestern part of the SEE. Methods. The material for writing the article was the results of drilling more than 10,000 exploration, structural and parametric drilling wells conducted during the State Geological Survey at scales of 1:50,000, 1:100,000 and 1:200,000, which are stored in the State Information Geological Fund of Ukraine. Also, the results of own field research of 47 most complete open sections of the Upper Cretaceous of Platform Ukraine were taken into account and a significant literature on the geological structure of the studied area was processed. Research methods: facies and formation analysis, lithological, petrographic, paleontological, litho-biostratigraphic, geophysical, etc. At the final stage of the mapping of the Upper Cretaceous sediments of Platform Ukraine, the methodology of sedimentary basin monitoring and modeling of formation units was used with the help of the domestic software package "Geomapping" with further conversion to the ArcView grid format. Results. To find out the spatio-temporal distribution of the Upper Cretaceous deposits of the study area, their composition, stratigraphic position and parameters of the Late Cretaceous sea basin, we analyzed the materials of mapping, structural search, exploratory and parametric drilling over the past 50 years were analyzed, our own studies of open sections of the Upper Cretaceous were taken into account, and significant stock material on the geological structure of the studied area was also processed. The most informative wells were selected as reference wells. Their number varied from 1179 for Early-Middle Cenomanian deposits to 1103 for Turonian deposits. The maximum density of the studied sections of support wells was recorded for the territory of Volyn-Podillia and individual blocks of the Ukrainian Shield (USH) and is 23.1 wells per 1000 km2, the minimum - in the water areas of the Ukrainian part of the Black and Azov Seas - about eight per 1000 km2. The absence of Upper Cretaceous deposits on a significant territory of platform Ukraine was established. Early-Middle Cenomanian and Turonian deposits have the largest distribution area, and Maastrichtian deposits have the smallest. In our opinion, areas with continental conditions of existence in certain ages or during the entire Late Cretaceous period have been identified. This made it possible to calculate the areas of land areas and areas covered by the sea with the help of software, with a certain percentage of error (up to 10%). The area of the sea basin was up to 80% of the territory of platform Ukraine. In the historical development of the Late Cretaceous Sea basin of the study area, two stages are distinguished: early-Middle Cenomanian and late Cenomanian-Maastrichtian, which differed significantly from each other in terms of hydrological, hydrochemical, temperature regimes and the nature of sedimentation. The lithological characteristics of the deposits according to the modern stratigraphic division of the Upper Cretaceous rock complex are given.

Dynamic complexes of aquatic landscapes in mixing zone of Don River and Taganrog Bay

One of the main peculiarities of aquatic systems over ground ones is their high mobility attributable primarily to the intensive water mass dynamics. The mixing zones of river and sea water are considered the most dynamic aquatic system where stream velocity change, wave action, and wind-induced currents lead to periodic changes in aquatic landscapes and their spatial attitude. These conditions lead to the creation of dynamic complexes of aquatic landscapes. Alongside with natural processes, mobility and changeability of aquatic landscapes is largely affected by anthropogenic factors. To reflect the dynamics of aquatic landscape, the term dynamic complex of aquatic landscapes is introduced. A dynamic complex of aquatic landscapes is a combination, on a specific defined area of a water body, of primal aquatic landscapes which, influenced by natural or anthropogenic factors, change their rank and/or positioning for a short or long period of time. In the mixing zone of the Don River and Taganrog Bay, 6 dynamic complexes were singled out: the delta of the Don, Taganrog Bay near-shore area, the eastern and the central areas of Taganrog Bay, the foreshore abrasion-rockslide area, and the area of cumulative spits. The main factors for the formation of dynamic complexes and transformation of aquatic landscapes are increasing amounts of total dissolved solids and reproportion of typomorphic ions; short-term increases in water salinity due to wind-induced activity; long-term increases in salinity due to an influx of large sea water masses from the central part of the Azov Sea; retrogression of the beach; and shifting of cumulative spits due to active wave effect. A task of utmost importance for geography and landscape science is studying the development of natural complexes. One of the main peculiarities of aquatic systems over ground ones is their high mobility attributable primarily to the intensive water mass dynamics. In the study of water bodies, the most common approach is the compositional one: water, bottom sediments, and hydrobionts are studied separately. At the same time, aquatic systems are complex combinations of aquatic landscapes where separate elements are closely interconnected. However, the peculiarities of formation and the dynamics of aquatic landscapes have been least studied.

First records of ratan goby Ponticola ratan in the Kaniv Reservoir and Desna River (Ukraine): A discreet invader of rip-raps

Monitoring of nearshore fish communities carried out in 2019 and 2022 in the Kaniv Reservoir and lower Desna River (Dnieper River basin, Ukraine) showed the presence of the ratan goby (Ponticola ratan), which has never been observed in these water bodies before and naturally inhabited marine and brackish waters of the Black and Azov Sea basins. The ratan goby was detected only on rip-rap structures and not on any other surveyed substrates including sand, mud, clay, and gravel which suggests a narrow habitat preference for this species. In all instances, the ratan goby co-occurred with the round goby (Neogobius melanostomus). Occurrence on all surveyed rip-raps, high abundances and the presence of a variety of size classes of the ratan goby in samples suggest that this species penetrated the Kaniv Reservoir quite long ago and successfully established there and has become a common component of the local fish fauna. Based on the obtained data, this gobiid should be listed among freshwater fishes of Europe as a euryhaline species that can potentially colonize other rivers flowing into the Black Sea including the Danube.

The Oligopolistic Behavior of Kazakh and Russian Wheat Exporters in the South Caucasus: Evidence from a Residual Demand Elasticity Analysis

This study looks at whether Kazakh and Russian wheat exporters leverage their dominant share of the wheat markets in the South Caucasus to exercise market power. We apply a three-stage estimation for systems of simultaneous equations and Zellner’s seemingly unrelated regression to analyze residual demand elasticity. The results of both estimations provide empirical evidence of Russian market power in the wheat markets of the South Caucasus but no evidence of a Kazakh oligopoly. Russian exporters possess greater market power in Armenia than in Georgia. Market power depends on the presence of competitors in the destination market. The results show that Kazakh exporters restrict the market powers of Russian exporters in the Azerbaijani wheat market, while Russian exporters constrain the market power of Kazakh exporters in the Azerbaijani and Georgian wheat markets. Ukrainian wheat exporters are able to intervene in the market powers of Russian exporters in Azerbaijan and Georgia, while they restrict Kazakh oligopoly in the Georgian market. Some export restrictions imposed by wheat exporting countries significantly affected competition in wheat importing countries. Russia’s ongoing war against Ukraine and the blockade of Ukrainian ports on the Sea of Azov and the Black Sea are restricting wheat trade, severely damaging Ukraine’s competitiveness and export potential, and reducing food security in the South Caucasus, the Middle East, and North Africa.

Harbors of Cape Tagan Rog

Based on chronological and systematic methods, the article examines the history of the creation and development of sea harbors on Cape Tagan Rog, starting from the VII century BC. Data from geology, archeology, historiography are used. It is shown that the location of the cape, the rich resource possibilities of the sea and the adjacent fertile lands for thousands of years attracted peoples who were at the peak of ethnogenesis: Hellenic Greeks, Pontic Greeks, Byzantines, Genoese and Venetians, Ottoman Turks equipped anchorages, harbors, strong points here. The naval base «City of Trinity» (Taganrog), created by Peter the I-st and resumed under Catherine the II-nd, the fl eet built and the decisive actions of the army changed the geopolitical situation radically in the region: Russia took control of the Sea of Azov, entered the Black Sea and gained access to the Mediterranean, pacifi ed the Wild Field and the Crimea. The city of Taganrog has become a commercial port with developed foreign trade relations. The presence of the port stimulated the development of industry and cultural ties. In the XX century the city harbors multiplied: the harbor of the metallurgical plant, the ship repair plant, the hydro-base of the aviation plant, yacht clubs, bases of fi shing and small vessels. Today the city has a special marine fl avor, a complex economic, social and cultural structure. Residents use a variety of opportunities for work, leisure and self-development. The results of further archaeological excavations at the cape and archival research will contribute to the education of Russians, broaden their horizons, form a fi rm civic position and a coherent system of views on the world.

Age Determination of the Azov Anchovy Engraulis encrasicolus maeoticus (Engraulidae) Based on the Otolith Image Analysis

To specify the age determination of the Azov anchovy Engraulis encrasicolus maeoticus, the length of otoliths of the age 0+ fish and the radii of annual rings in the otoliths of individuals of different age groups have been analysed. The otoliths of 380 fish caught in the Sea of Azov in October–November 2018 and off the northwestern coast of the Caucasus in February 2019 have been analyzed. The ImageJ software has been used for measuring the maximum otolith length and plotting the reflected light intensity profiles along the length of the otolith transect. In the fingerlings (0+) with an average total length of 70.9 ± 6.7 mm, in October–November, the otolith radius averaged 0.95 ± 0.08 mm, while in February, with an average 66.6 ± 10.6 mm, it was 0.86 ± 0.15 mm. In the smallest fish (48–55 mm), the distance from the core of the otolith to the edge of the white opaque zone varied from 0.54 to 0.72 mm (on average, 0.63 ± 0.04 mm). According to the averaged data, the radii to the center of the dark hyaline zone of otoliths for different age groups of anchovy are: R1, 0.94 ± 0.09; R2, 1.23 ± 0.08; and R3, 1.40 ± 0.07 mm. The present study is aimed at developing automatic methods for determining the age of fish from light intensity profile peaks on otolith images.

Transformation of Malacological Fauna of the Sea of Azov in the Holocene and Its Role in the Formation of Coastal Spits

The study and analysis of malacofauna from cores of bottom sediments and cores of the Azov spits showed the nature of the change during the transition from the Ancient Azovian to the New Azovian layers and the uneven distribution of communities in time and space. Shell material from littoral malacocenosis and shallow-water banks is the main component for the formation of spits. Based on a series of cores up to 25 m thick from the Dolgaya Spit, it is shown that its formation began about 2500 years ago, and carbonate material reflects the history of the development of the benthic fauna of the sea.

MYSTERIOUS RITUAL OBJECTS OF THE SCYTHIANS: SEARCHING THE ANSWERS

The paper is devoted to the analysis of versions of the probable use of gold cone-shaped objects that were in use from the last decades of the 6th centuries BC to the end of the 4th centuries BC. They are differ in size (base diameter varies from 5 to 19.8 cm, height — from 4 to 18 cm) and some shape features. At the same time, they are characterized by hollowness, a wide round base, which is usually 1.2—2.0 times greater than the height, and the obligatory presence (with two exceptions) of a small round hole in the «upper» part. All of them are made of gold or covered with this precious metal. Currently 26 such objects are known, and they originate from 19 assemblages from the Northern Pontic and Azov Sea regions (12), the Middle Don (1), the North Caucasus (2) and the Southern Urals (4).
 The context of finding objects is considered in detail. It is concluded that they were mostly worn attached to the gorytos. This is also confirmed by the images on the stone sculpture. It is believed that the cones could have been a decoration of the gorytos or a sign of prestige. But, probably, the purpose of these items was different. Some of the cones were found in ritual complexes — hiding places within the burial chamber or next to the burial.
 Researchers have put the different versions of the possible functional purpose of cone-shaped objects: ritual objects, part of a ceremonial headdress; a cap for tassels that were tied to the horse’s neck; pommel of a standard or staff; «case» for storing scalps; censer; ritual utensils. But most versions are based on arbitrary assumptions that contradict both the archaeological context of the find and the general cultural context.
 From all versions, it is probable that the majority of the cones were used as ritual vessels for sacrifice by pouring out liquid. In several cases, these objects were found in caches together with ritual utensils. Other examples of ritual vessels with holes in the bottom are known. Some objects have a decoration in the form of a rosette (it surrounds the hole) which is placed only at the bottom of the bowls. It is possible that Herodotus’ information about the bowls that the Scythians wore on their belts is related to these objects. They could be used for sacrifices to «Scythian Ares», which we also know about from Herodotus’ «History».

Изучение состояния зоопланктона, ихтиопланктона и зообентоса в акватории Азовского моря в позднеосенний период 2021 года

The article presents the results of hydrobiological monitoring of the water area of the Sea of Azov in the late autumn period of 2021. The characteristics of the taxonomic composition and quantitative indicators of zooplankton and zoobenthos are given, the distribution of hydrobionts by dominant species is shown, and saprobity indicator species are noted.

Seasonal Changes in Abundance, Biomass, and Species Composition of Zooplankton Communities in the Open Sea near the Crimean Coast of the Black Sea and Sea of Azov

Seasonal Changes in Abundance, Biomass, and Species Composition of Zooplankton Communities in the Open Sea near the Crimean Coast of the Black Sea and Sea of Azov

MATHEMATICAL MODELING OF THE RELIABILITY OF MIXED CARGO TRANSPORTATION UNDER DYNAMIC CHANGE OF CONDITIONS

Topicality. Military threats determined the significant pace of changes in the risks of mixed cargoes transportation and proved the need for new methods of ensuring the reliability of transportation. First of all, there was the problem of assessing the levels of transportation reliability along individual routes and modeling a possible change of routes with the choice of safer options and ways of transportation. A particularly important function of such a model, due to the rapid pace of changes in risks, is the possibility of its practical application in real-time conditions.Aim and tasks. The purpose of the work is to develop a mathematical model of mixed cargo transportation in the conditions of dynamic changes in risks to increase the reliability of the transportation process, analyze alternative options for transportation, and identify opportunities for changing the route even in the process of cargo transportation. Achieving the goal of the study made it necessary to set and solve the following tasks: to implement the possibility of analyzing alternative transportation options and proposing route changes in real time; prove the capabilities of the developed model on the example of specific enterprises; to ensure reliability forecasting of the next cargo transportation stages; implement the possibility of optimizing multi-purpose tasks to ensure reliability, minimize the cost and time of transportation; to stratify the reliability of cargo transportation according to the level of threats probability.
 Materials and methods. Various general and special methods of knowledge were used in the work: the method of quantitative and qualitative comparison for the stratification of the cargo transportation reliability depending on the risks at individual stages; methods of vector analysis to take into account the probability of the cargo transportation risk at each stage of mixed transportation; the method of induction and deduction made it possible to consider the reliability of the transportation as the reciprocal of the transportation risk probability; the task fragmentation method allows to include probable stages of transportation in different transport routes; a method of mathematical formalization of the problem for the formation of a model of mixed cargo transportation using water transport in conditions of dynamic changes in risks.
 Research results. A mathematical model of mixed cargo transportation in conditions of dynamic changes in risks was developed to increase the reliability of transportation, analyze alternative transportation options, and identify opportunities for changing the route during cargo transportation. To solve this, the following tasks were developed: a mathematical model capable of analyzing alternative transportation options and proposing route changes in real life was developed; proven possibilities of the model on the example of specific enterprises; forecasting of the reliability the next cargo transportation stages is ensured; the possibility of optimizing multi-purpose tasks to ensure reliability, minimizing the cost and time of transportation has been implemented; stratification of the reliability cargo transportation by the level of probability threats was carried out.
 Conclusion. Using the model, the activities of enterprises that transported their products through the ports of the Sea of Azov were analyzed. Due to the decrease in the reliability of cargo transportation through the Kerch Strait, alternative routes for the transportation of mixed cargo are proposed, for the use of "river-sea" vessels at certain stages. Approbation of the model for increasing the efficiency of the transport and logistics process of enterprises proved its effectiveness. The use of the developed mathematical model for the analysis of enterprise activity indicated an implicit advantage of increasing the level of transportation reliability, in particular, in relation to identifying the possibility of reducing warehouse stocks with a significant saving of working capital at the same time. The presented results of the research make it possible to ensure the proper reliability of transportation of mixed cargoes, even in conditions of significant dynamic changes in the level of threats on transportation routes.

Marine indicators of climate change in the Azov Sea ecosystem

The study is a contemporary overview of accumulated data and knowledge about the state of water resources in the Sea of Azov basin. The focused area has been rather thoroughly studied since the 1970s, however the information presented in the literature sources is mainly in Russian. The main research objective is to consider the changes that occurred in the second half of the 20th – early 21st centuries in the lower reaches of the Don and Kuban rivers as a result of economic development of the territory (construction of water-storage reservoirs, dams, irrigation canals, etc.). We provide the most complete summary of data on the inter-annual and seasonal variability of water and solid river runoff, the nutrient load on the ecosystem of the Sea of Azov, as well as new data on the dynamics of organic carbon in the Don runoff in the recent low-water period of 2007–2020. The most significant changes include redistribution of river runoff during the year, a catastrophic reduction in solid runoff, and a change in the structure of terrigenous matter entering the sea. In conclusion, we indicate the chains of consequences of long-term changes in water, solid, and nutrient river runoff for the ecosystem of the Sea of Azov. These include changes in seawater salinity and temperature, terrigenous sedimentation, chlorophyll-a concentration, primary production values, the relative amount of organic matter in bottom sediments (one of the causes of oxygen deficiency at the bottom), structure of planktonic and benthic organisms, as well as in dynamics of valuable commercial fish populations. In particular, we discuss recent observations that confirm the earlier long-term probabilistic forecast of the collapse of the Azov pikeperch population in the beginning of the 2000s. We consider the salinity and temperature of sea waters, data on the content of diatom valves, and the appearance of the Black Sea benthic species in the ecosystem of the Sea of Azov as reliable indicators of climate change. Some of the observed phenomena are still poorly explained and require further research. Using the example of the Sea of Azov and the rivers flowing into it, we indicate how climate variability and economic activity affect the state and functioning of marine ecosystems. Some identified regularities of the processes occurring in the Azov Sea ecosystem may be applied to other water bodies (marine areas).

Morphometric analysis of the large en- closed depression of the Southern East European plain

The results of morphometric analysis based on the SRTM digital elevation model of large enclosed depressions (LEDs) of controversial origin, commonly found on the loess interfluves in the Northern Black Sea region, around the Sea of Azov, at the Western flanks of Caucus Mountains and in the Lower Don basin, are presented in the paper. We have registered 312 LEDs landforms. The morphometric characteristics of landforms vary from 0.4 to 216 km2 for area, from 1 to 21 m for depth, from 0.5 to 13.3 km for width, from 0.7 to 27.5 km for length, from 1 to 4 for elongation coefficient, and from 3.3 to 103.3 m a.s.l for height. The most common depressions have the following parameters: area 24 km2; depth 23 m; width 1.01.5 km; length 2.53.0 km; elongation coefficient 1.21.4; height 1520 m a.s.l. There is a correlation between the area and depth of the depressions. The depressions' shape is mostly elongated, e. g. teardrop-shaped, eggshaped, elliptical, triangular, and rarely round. The sharp ends of the egg-shaped depressions always tend to point to the north, and the blunt ones to the south. We grouped the depressions into seven restricted sites where the differences in size and other morphological features of the LEDs are very small. Within all sites, there is a high consistency of orientation of the long axes of the depressions. The largest depressions around the Sea of Azov and the Western flanks of Caucus Mountains are characterized by longitudinal ridges confined to western side of LEDs. Comparison analysis of sites demonstrated a fan-shaped pattern in changing of the long axes orientation from the NW in the Northern Black Sea region; to the East in the Azov Sea region; to the N in the Western flanks of Caucus Mountains; and the NE in the Central flanks of Caucus Mountains. A radial-centripetal pattern of the erosion network is observed across the territories where LEDs are distributed. Small erosive forms flowing into the center of depressions are represented by very flat and wide gullies and hollows with intermitted channel flow. Such morphological characteristics suggest the relict origin of the erosional forms and, as a result, indicates the pre-Holocene age of the depressions themselves. Morphological and geological data suggests that wind erosion was probably the main factor in the formation of LEDs.

Comparative Morphometric Analysis of the Azov Anchovy (<i>Engraulis encrasicolus maeoticus</i> Pusanov, 1926) and the Black Sea Anchovy (<i>E. encrasicolus ponticus</i> Alexandrov, 1927) Based on the Body Shape

A comparative analysis of body shape was performed on 841 specimens of anchovy collected from 21 catches from the Sea of Azov, the Kerch Strait, and the Black Sea off the Crimea and the northeastern coast of the Caucasus in 2006–2007 and 2016–2017. Twenty-three measurements between 12 homologous landmarks of the body of each specimen according to the “Truss Network System” served as characters for analysis. Fifteen characters showed significant differences between the Azov anchovy Engraulis encrasicolus maeoticus Pusa-nov, 1926 and the Black Sea anchovy E. encrasicolus ponticus Alexandrov, 1927. Specimens of the Azov subspecies had larger relative values for all characters of the head region, the height of the trunk region, the re-lative length of the bases of the dorsal and anal fins, and the height of the base of the caudal fin. Specimens of the Black Sea subspecies had a greater postdorsal length and a larger distance from the end of the dorsal fin base to the end of the anal fin base. A multivariate principal component analysis revealed the highest variabi-lity of characters of body height, which depends on the fatness of the fish and demonstrates seasonal dyna-mics. The second group combines characters that do not have a seasonal component (dimensions of the head region, lengths of the bases of the dorsal and anal fins, and postdorsal distance) and can be used for distinguishing the shape of the Azov and Black Sea anchovies. The success rate of classification of Azov and Black Sea anchovies according to the body shape measurement characters using the discriminant analysis was 83.4%.

Seasonal Changes in Abundance, Biomass, and Species Diversity of Zooplankton in Areas Offshore the Crimea (Black and Azov Seas)

New data are presented the seasonal changes in abundance, biomass of copepods and fodder zooplankton in areas offshore the Crimea. These investigations are based on the materials of five expeditions of the RV “Prof. Vodyanitsky” in the northern part of the Black Sea and the southern part of the Sea of Azov in different seasons of 2016. It was shown: 1) Seasonal differences in the taxonomic structure of the Copepoda taxocene from the shelf and deep waters were revealed. The warm-water invasive species Acartia (Acanthacartia) tonsa and Oithona davisae were relative numerous in the copepod assemblages on the shelf in summer and autumn. In the deep waters, with a low abundance of warm-water invaders, cold-water native species were dominating, and the structure of the Copepoda taxocene was more stable than on the shelf in these seasons. 2) Zooplankton abundance in 2016 was higher compared to 2010 and the 1990s. The data on zooplankton, supported by information about an increase in the species richness and abundance of fish larvae in recent years, make it possible to talk about the transition of the Black Sea ecosystem to a new, relatively stable state.

Biology and Distribution of Stellate tadpole-goby Benthophilus stellatus and Don tadpole-goby B. durrelli (Teleostei: Gobiidae)

Size-age and sex population structure have been studied for the aboriginal stellate tadpole-goby Benthophilus stellatus and Don tadpole-goby B. durrelli in the Don River basin. The females of Don tadpole-goby mature at a body length of about 35 mm, stellate tadpole-goby females, at 50 mm. Most breeders of Don tadpole-goby (~74%) are characterized by one-time spawning, stellate tadpole-goby spawns three times. The duration of the breeding season is about 3.5 and 1.5 months, the individual absolute female fecundity is 0.2–0.6 and 1–3 thousand eggs, respectively. All breeders of Don tadpole-goby die after spawning in the second year of life, an insignificant part of stellate tadpole-goby population lives up to three years. The food spectra, size and biotopic variability, the degree of food similarity, and the selectivity of food organisms in both species have been analyzed. The species are characterized by the similarity in feeding and high feeding flexibility. In the Tsimlyansk Reservoir, the main food objects for tadpole-gobies are mosquito larvae and the mollusk Lithoglyphus naticoides, in the lower reaches of the Don River, various crustaceans. We assume three species of tadpole-goby (Don, stellate tadpole-goby and Makhmudbekov tadpole-goby B. mahmudbejovi) inhabit currently in the Volga River reservoirs. Don tadpole-goby has also settled in the lower reaches of the Volga River. Apparently, its range includes the Black Sea, in addition to the native Sea of Azov and newly mastered Volga River basins.