Functioning of the Sea of Azov ecosystem

The structure and functioning of the Sea of Azov ecosystem have been studied. Based on the results of an analysis of the principal community components (phytoplankton, bacterioplankton, zooplankton, macrozoobenthos, and fish), the elements of balance equality and food utilization by the ecosystem components were calculated and schemes of their energy flow were constructed. The intensity and trends of production-destruction processes were characterized. It was revealed that the main energy flow in the Sea of Azov ecosystem passes through the detritus food web (81%). Along with eutrophication and sulfide pollution of bottom sediments, the impact of predatory ctenophore Mnemiopsis leidyi (A. Agassiz) determines to a considerable extent the pattern of the ecosystem’s transformation.     

Azov Anchovy Engraulis encrasicolus maeoticus (Engraulidae) under the Sea of Azov Salinization in 2014–2018

Journal of Ichthyology - The paper considers the effect of the Sea of Azov salinization on the food supply to anchovy Engraulis encrasicolus maeoticus as the level of salinity was rising from 12.7...     

The microphytobenthos of the Sea of Azov

This review examines the state of knowledge of microphytobenthos of the Sea of Azov. The insufficient number of floristic studies and the almost complete lack of quantitative data on populations and communities of microalgae in different marine ecotopes demonstrate the relevance of studying the microphytobenthos.     

Taxonomic composition and interannual variations in numerical density of meroplankton in the Sea of Azov

This paper presents data on the taxonomic composition and dynamics of numerical density of meroplankton in the Sea of Azov. Studies performed in June 2003–2005 revealed benthic invertebrate larvae of 26 taxa: Polychaeta, 7; Cirripedia, 1; Decapoda, 5; Gastropoda, 5; and Bivalvia, 8. Meroplankton was dominated by larvae of species that are able to endure considerable concentrations of pollution by labile sulfides in bottom sediments and eutrophication: Mytilaster lineatus, Cerastoderma sp., Abra ovata (Philippi), Hydrobia acuta (Gastropoda), and Amphibalanus improvisus (Cirripedia). The spatial and temporal variations in the structure of dominant species and numerical abundance of meroplankton in the Sea of Azov are likely to be associated with water temperature fluctuations, pelagic predators, and eutrophication. Under anthropogenic stress and predation pressure, most larvae of benthic invertebrates are apparently unable to complete metamorphosis and contribute to recruitment to parental populations. Thus, the numerical density of meroplankton in the Sea of Azov can significantly vary, even over one month.     

Composition and Seasonal Succession of Phytoplankton of Taganrog Bay in the Sea of Azov and the Downstream Reaches of the Don River under a Changing Climate

Inland Water Biology - The results of a study of phytoplankton in Taganrog Bay in the Sea of Azov and the downstream reaches of the Don River carried out in January–November 2017 are...     

Radioecological problems in coastal landscapes of the Sea of Azov

The features of the spatial distribution, of the migration, and of the accumulation of natural (232Th) and manmade (137Cs) radioactive nuclides in the coastal landscapes of the Sea of Azov are studied. It was shown, that the specific activity of 232Th in the accumulation of the so-called "black sands" was shown as high as 6000 Bq/kg, that increases the natural geochemical background in 200 times. The impact of aerial transfer of the "black sands" on 232Th migration and accumulation in the soil-plant system was clarified. The 232Th distribution down the soil profile suggests that the "black sands" are likely the product of the erosion of the coastal parent materials enriched by natural radionuclides. In general, the specific activity of 137Cs in the beach sand is not high and it is close to the background (global fallout) value. It was determined that 137Cs content in the coastal ecosystems is connected only by aerial pathway as a part of global and Chernobyl-born fallout.     

Population structure of haarder <Emphasis Type="Italic">Liza haematocheila</Emphasis> (Mugiliformes,Mugilidae) acclimatized in the Sea of Azov Basin

As a result of the successful acclimatization in the Azov basin, haarder Liza haematocheila has become a commercial species and is currently among the main commercial items. Its reproduction in the new range takes place in environmental conditions strongly differing in the salinity level (3–24‰), which determined its population differentiation. The extent and structure of the phenetic diversity of L. haematocheila from the Sea of Azov basin was assessed and elucidated, using a phenetic approach in studies of natural populations and on the basis of studying morphological characters. Molochnyi Liman, Sivash, and marine subpopulations of L. haematocheila were distinguished.     

A Comparative Analysis of Biochemical Parameters in the Liver of Round Goby Neogobius melanostomus (Pallas, 1814) from Two Regions of the Taganrog Bay (Sea of Azov)

Russian Journal of Marine Biology - Bioindication assessment of two areas in the Taganrog Bay (Sea of Azov) was carried out using biochemical parameters (activity of antioxidant enzymes (superoxide...     

Clinico-epidemiological characteristics of diseases caused by halophilic vibrios along the coast of the Sea of Azov

The epidemiological and clinical features of alimentary toxinfections caused by halophilic vibrios on the Crimean coast of the Sea of Azov at the period of 1976-1984 were studied. Toxinfections were linked mainly with the use of sea-food subjected to different kinds of culinary treatment and took the course of gastroenteritis. To prevent toxinfections caused by halophilic vibrios, the technology, as well as sanitary and hygienic norms, should be strictly observed in the production of sea-food; besides, special methods of bacteriological diagnosis should be introduced into practice at laboratories of medical institutions and fish-processing plants.     

A Review of the Genus Apocopta Falkovitsh, 1987 (Lepidoptera,Coleophoridae) with a Description of a New Species from Crimea and the Sea of Azov Region in Ukraine

Entomological Review - Data on ten species of the genus Apocopta Falkovitsh, 1987 are summarized. Apocopta longivalvella sp. n. is described from Crimea and the Sea of the Azov Region in Ukraine....     

The role of zooplankton in the functioning of the Taganrog Gulf ecosystem in the Sea of Azov

The taxonomic composition, distribution of biomass and seasonal variability of zooplankton were studied in various areas of the Taganrog Gulf of the Sea of Azov. The structural-functional transformation of zooplankton was analyzed for ecosystems of various levels of organization (the hypereutrophic central and eutrophic western parts). Unusually strong water blooming caused by cyanobacteria and the pressure of predatory comb jelly results in the elimination of zooplankton, the simplification of the trophic web, and the loss of the ecosystem’s capacity for biotic self-purification. The considerable participation of microzooplankton, especially that of tintiniids, in the metabolism of the Taganrog Gulf ecosystem is one of the important features of its sustainable functioning.     

Variation of the External Characters and Taxonomic relationships of Azov and Black-Sea populations of Percarina demidoffii (Percidae)

A variation analysis of the external characteristics used previously for the differentiation of the Azov P. maeotica and Black Sea P. demidoffii as independent tax a of the species or subspecies rank is made on museum materials. All previously used characteristics are demonstrated to be devoid of a diagnostic value. At present, there is no reason to divide the Azov-Black Sea populations of P. demidoffii into independent taxonomic units.     

A biometric method for determining the sex of acipenserids, including the Russian sturgeon Acipenser gueldenstaedtii (Acipenseridae) of the Azov Population

With reference to the Russian sturgeon Acipenser gueldenstaedtii of the Azov Population, it is demonstrated that the sex of acipenserids may be determined biometrically. A measurement scheme of the head is suggested, which gives the possibility to determine gender in live sturgeons. A discriminate equation is composed for the identification of the sex of individuals of the Russian sturgeon in a sufficiently wide size-age range, irrespective of the maturity stage of the gonads.     

Seasonal dynamics of activity of oxidative modification of proteins and oxidation-inhibiting enzymes in the blood of goby Neogobius melanostomus inhabiting the Black Sea and the Sea of Azov

Seasonal dynamics of activity of oxidative modification of proteins and oxidation-inhibiting enzymes was studied in the blood of round goby Neogobius melanostomus that inhabits the coastal areas of the Black Sea and the Sea of Azov. The activity of oxidative modification of proteins and oxidation-inhibiting processes depend on the physiological state of a peculiar specimen, on the hydrochemical parameters of the environment, and on the anthropogenic load in the studied areas during different seasons.     

New strategies for brood stock management of sturgeon in the Sea of Azov basin in response to changes in patterns of spawning migration

The sturgeon stock in the Sea of Azov is presently maintained by artificial reproduction allowing for the harvest of sturgeons in this basin. Shortened spawning migrations in regulated rivers and long-term artificial selection of the ripest fish at the hatcheries have resulted in high functional maturity of sturgeon spawners in the sea near the river mouth. The traditional technology of artificial sturgeon reproduction is non-effective under modern ecological conditions. The use of ecological and hormonal methods to control seasonal propagation of stellate sturgeon, A.stellatus , Russian sturgeon, A.gueldenstaedti , beluga, Huso huso , and sterlet, A.ruthenus , make it possible to stagger the sexual cycle of breeders from the various biological groups for early (5 months) or later (6 months) spawning. Use of these methods preserves the natural heterogeneity of sturgeon populations maintained through stocking, and also allows for a considerable increase in the quantity of fry reared at the same production base.
The use of the synthetic analogue of mammalian gonadotropin-releasing hormone (Gn-RHa) is better for inducing maturity of the ripest brood fishes, especially for stellate sturgeon, in comparison with the traditional pituitary injections. The schedule of injections was determined for the various species and seasons of spawning.
Short-term rearing of larvae in ponds (no more than 15 days) and subsequent adaptation to sea water in brackish lagoons (1–5 %o) allows for repeated use of nursery ponds in sturgeon hatcheries and a considerable increase in the quantity and survival of sturgeon juveniles in the sea.
The restoration of the sturgeon population structure in the Sea of Azov is not possible without developing a genetic collection of the fish under a controlled culture regime.     

Distribution and cytogenetic features of triploid male goldfish from Azov basin

When studying uni-bisexual goldfish (Carassius auratus gibelio) populations in the Azov basin in 1995-2000, we found triploid males, which constituted 2.5%, on average, of the total numbers of studied samples. The areas of nuclei of erythrocytes of triploid males were, on average, 1.35 times those in diploid males. At the same optical density of DNA, the sizes of mature spermatozoon heads in triploid males were, on average, 1.8 times smaller than in diploid males, as follows from the data obtained in 1966. The results of similar studies carried out during the period of natural spawning activity in 1997-1999 suggest that the sizes of spermatozoon heads suggest that the sizes of spermatozoon heads in triploid males were, on the contrary, 1.5 those in diploid males. Triploid males were characterized by mosaicism of spermatozoon size and chromosome mosaicism in somatic cells. Electrophoretic analysis for the locus of transferring confirmed the triploid status of this genetic group. The results of comparative crosses of goldfish with different ploidy suggest a high fertilizing capacity of triploid males, as well as normal viability of their progenies. A distinct positive correlation (r = 0.73) was found between the numbers of triploid females and triploid males in mixed di-triploid populations. No significant correlation was found between males and females within di- or triploid populations.     

Distribution and Cytogenetic Features of Triploid Males of Crucian Carp in Azov Basin

When studying uni-bisexual crucian carp (Carassius auratus gibelio) populations in the Azov basin in 1995–2000, we found triploid males, which constituted 2.5%, on average, of the total numbers of studied samples. The areas of nuclei of erythrocytes of triploid males were, on average, 1.35 times those in diploid males. At the same optical density of DNA, the sizes of mature spermatozoon heads in triploid males were, on average, 1.8 times smaller than in diploid males, as follows from the data obtained in summer 1996. The results of similar studies carried out during the period of natural spawning activity in 1997–1999 suggest that the sizes of spermatozoon heads in triploid males were, on the contrary, 1.5 those in diploid males. Triploid males were characterized by mosaicism of spermatozoon sizes and chromosome mosaicism in somatic cells. Electrophoretic analysis for the locus of transferrin confirmed the triploid status of this genetic group. The results of comparative crosses of crucian carps with different ploidy suggest a high fertilizing capacity of triploid males, as well as normal viability of their progenies. A distinct positive correlation (r = 0.73) was found between the numbers of triploid females and triploid males in mixed di-triploid populations. No significant correlation was found between males and females within di- and triploid forms.     

Determination analysis as a tool to study relationships between ecosystem components in water bodies of the Azov, Caspian, and Kara Sea basins

Contingencies of different components of freshwater biocenoses in the Don, Volga, Angara, and Northern Azov basins where studied by determination analysis. A positive contingency between the biomass of total phytoplankton or its divisions and the biomass of zooplankton was demonstrated. The most significant contingencies were revealed for zooplankton and green algae, dinoflagellates, and cyanobacteria. As against zooplankton, the biomass of zoobenthos features much less contingencies with the biomass of microalgae as well as zooplankton, since detritus, higher plant tissues, and small animals are the basis of the diet of benthic organisms. Differences in the contingency pattern between different geographical regions and time periods within the same basin have been revealed using the context procedure in determination analysis.     

Mitochondrial DNA divergence and phylogenetic relationships in mullets (Pisces: Mugilidae) of the Sea of Japan and the Sea of Azov revealed by PCR-RFLP-analysis

Three Mugilid species: Mugil cephalus (Linnaeus, 1758) and Liza haematocheila (Temminck et Schlegel, 1845; syn. Mugil soiuy, M. haematocheilus, L. soiuy, Chelon haematocheilus) from the Sea of Japan, as well as M. cephalus and Liza aurata (Risso, 1810) from the Sea of Azov were investigated on the basis of PCR-RFLP analysis of mitochondrial DNA (mtDNA) fragments, which included 12S/16S rRNA, and ND3/ND4L/ND4 genes. Among 61 individuals of three Mugilid species thirteen different haplotypes were detected. Eight and thirteen restriction endonucleases were found to be species-specific in 12S/16SrRNA and ND3/ND4L/ND4 respectively. This method may be useful for species identification. M. cephalus showed the largest genetic divergence while L. haematocheila and L. aurata were closely related and clustered together. The level of mtDNA differentiation between the two M. cephalus samples from the Sea of Japan and the Sea of Azov, i.e., nucleotide substitutions of approximately 3%, appeared to be relatively high.