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On the development of Azov sturgeon breeding on the occasion of the 150th anniversary of sturgeon culture in RussiaВодные биоресурсы и среда обитанияThis article presents a retrospective review of sturgeon breeding evolvement in the Azov Sea Basin. A particular emphasis is placed on the research covering breeders and rearing of juveniles; the development of efficient long-term practice of their culture has been a subject of the institute's research for many years. The best practices of using the individuals at different points of their spawning run (autumn, spring, summer) and different places of capture along their spawning migration route (Taganrog Bay, river deltas, dam-adjacent sites) for breeding purposes in culture have been identified for each species (great sturgeon (beluga), Russian sturgeon, stellate sturgeon) stage by stage on the basis of morphophysiological investigation of heterogeneous individuals belonging to each investigated group of breeders. Special attention was paid to gonad maturity stages in females, and receptivity of oocytes to fertilization. The reasons for the current low recruitment to the stocks of sturgeon species from cultivated generations have been identified; they include reproductive potential of the females from a farmed broodstock and the state of sturgeon hatcheries that calls for an update of their technical equipment and facilities. It is obvious that the Azov sturgeon stock enhancement cannot be steered out of this crisis without the government support, neither at present, nor prospectively. This article also names the most outstanding researchers in sturgeon breeding (biologists, physiologists, fish farmers), who played an important role in the development of the Azov sturgeon culture.
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Investigation of microbiological indicators of calcium food additive derived from veined rapa whelk Rapana venosa shellsВодные биоресурсы и среда обитанияThe relevance of this research is conditioned by the absence of industrial utilization of the waste discarded while processing the veined rapa whelk (shells), despite the fact that this mullusc is caught in the Azov and Black Sea Fishery Basin annually. As a result of processing 2,746.1 tonnes of rapa whelk caught in the Azov Sea in 2019, almost 2,000 tonnes of shells were derived. The microbiological safety indicators of the calcium feed additive derived from veined rapa whelk have been investigated, which was necessitated by the parts of mollusc viscera remaining in 50 % of shell cones after their processing. Samples of the calcium feed additive were prepared in 5 ways, differing in temperature (20, 80, 105 °C) and duration of drying (12 and 24 hrs, 3 and 9 months), as well as the presence/absence of viscera remains. The total bacterial load in all samples did not exceed the established norms (no more than 5×105 CFU/g); E. coli bacteria, Staphylococcus aureus and pathogenic microorganisms, including salmonella, have not been detected. Thus, the investigated methods of calcium feed additive production can be considered as alternative ones, ensuring the microbiological safety of this type of product with a shelf life of at least 3 months, while in paper bags.
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Revision of standardization documents on air-dried fish to ensure their compliance with the requirements of TR EAEU 040/2016Водные биоресурсы и среда обитанияFish products, obtained through curing, drying and dry-curing processes, are in great demand among the population and represent a ready-to-eat food item. This article presents a comparative analysis of the requirements of TR EAEU (Technical Regulation of the Eurasian Economic Union) 040/2016 and standardization documents to the moisture content in cured, dried, dry-cured and air-dried fish; inconsistency in these requirements, which should be eliminated during revision of the specifications for the indicated types of products, is identified. Results of the investigation of moisture content, conducted on samples of the cured and air-dried fish distributed through a market chain, are presented; they have shown that the major part of the investigated products did not meet the norms of moisture content, prescribed by the standards. For this reason, labeling of these products can be viewed as misleading in terms of complete and accurate information on a food item. Another requirement of TR EAEU 040/2016 to the cured and air-dried fish - presence of the characteristics of an ripened product - has also been analyzed. This article points out that the standardization documents do not provide biochemical indicators that could make it possible to evaluate the process of ripening in cured and air-dried fish; ripening characteristics are conveyed verbally along with the description of organoleptic properties. In terms of buffer value, investigation of the ripening level of cured and air-dried fish, distributed through a market chain, has shown it to be low for the products derived from lookdown, Black Sea horse mackerel, goby, Atlantic mackerel, and Atlantic herring, as compared to cured and air-dried Caspian roach. This article indicates that the presence of characteristics of ripened products cannot include all fish species used for production of cured and air-dried fish. Results of the conducted analysis have been used in development of the international standard for air-dried fish.
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Prospective uses of the macrophyte storm debris in the wrack zone of the Azov and Black Sea Fishery Basin (review)Водные биоресурсы и среда обитанияMass aggregations of brown algae Cystoseira and seagrass Zostera (eelgrass), which are formed along the wrack line during storms and natural exfoliation, can be considered one of the underexploited primary resources of the Azov and Black Sea Fishery Basin. As a rule, the process of their aggregation falls on the summer - autumn season, which coincides with the high season, leading to people's discomfort during their recreation time. Therefore, the issue of the prospective utilization of algae storm debris, its harvesting and primary processing can be deemed quite vital. The investigated macrophytes, washed ashore during storms or seasonally, are the source of valuable materials; Zostera provides zosterin and fiber, and Cystoseira is rich in alginic acid, iodine and selenium. This article considers proven methods of algae processing for nutritional purposes, obtaining dietary supplements and cosmetic products, in paper manufacturing, and the use of macrophytes as fertilizers and animal fodder. The methods of primary processing, entailing the best possible preservation of quality of the investigated algae and involving the processes of drying, freezing and chemical treatment, are studied. Specifics of algae storm debris collection and the necessity of timely removal of macrophytes from sandy coastline are indicated. Recommendations on natural and artificial drying, freezing and salting of macrophytes are given.
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Morphological features of oogenesis of the Pacific oyster (Crassostrea gigas, Thunberg) introduced into the Black SeaВодные биоресурсы и среда обитанияMorphological features of the Pacific oyster (Crassostrea gigas, Thunberg) oogenesis in the course of two-year cultivation cycle in Donuzlav Liman have been studied. The data on morphophysiological characteristics of this species (diameter and volume of acini, oocytes, nuclei, nucleoli, as well as the nucleoplasmic index) are given for different seasons. Quantitative changes in the size of oocytes (D) are presented in relation to water temperature (T, °С), which is described by the logistic function equation. It is shown that the dynamics of oogonia number (Nо) is linked to water temperature (T) with an inverse relation and is described by an exponential equation. The synchronicity of the changes in volumes of acini, oocytes and cell nuclei in the course of the reproductive cycle is shown, as well as the interrelationship between the volumes of these components. There was found to exist an asynchronicity in nuclei functioning and the nucleoplasmic index in the process of reproduction, which is linked with the synthesis of ribosomal proteins. Following the obtained data, 1-to-6 score of the maturity stages for the Pacific oyster females in the course of annual reproductive cycle is presented: passive state; beginning of oogenesis; active oogenesis; pre-spawning state; maturation and spawning; post-spawning transformation. The months, during which each maturity stage was the most prevalent, are given.
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Phytoplankton-based biomonitoring in assessing the pollution level of a lentic freshwater body in Hooghly District, West Bengal, IndiaВодные биоресурсы и среда обитанияPhytoplankton is the base of every aquatic food web. During the assessment of the trophic status of the investigated lentic water body (within Lake City Housing Complex, Mankundu, Hooghly, West Bengal, India), phytoplankton composition and its temporal variation are proved to be the most important. In this study, 30 phytoplankton taxa have been recorded in various arrangements throughout the season. The maximum number of phytoplankton species with the highest Shannon–Weaver diversity index value represented the pre-monsoon season, whereas the least number of phytoplankton taxa and the lowest diversity indicators characterized the post-monsoon season. The development of algal bloom by one specific taxon, Botryococcus braunii, in the postmonsoon season indicates the change in the trophic status of this particular water body. As a criterion for the beginning of the algal bloom, an exceedance of 1 mg/L in nitrate concentration can be considered. The phytoplankton composition, values of various diversity indices, its density and species distribution pattern, and selected environmental parameters have been investigated, as well as the results of the analysis of rank abundance curves, which allowed for evaluation of the ecological status of this lentic water body. This study describes the change or shift in the ecosystem of the investigated water body towards eutrophication and establishes its pollution level as moderate to light.
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Black Sea–Caspian sprat (tyulka) industrial fishing in the Azov Sea: Presently used fisning gear, methods, and its current trendsВодные биоресурсы и среда обитанияThis paper presents the main fishing methods and gears previously used or appraised and currently applied in the course of Black Sea–Caspian sprat (tyulka) fishing in the Azov Sea: their performance, merits and demerits. Black Sea–Caspian sprat (tyulka) fishing comprises the coastal fishing with pound nets and the fishing off the board of fishing vessels with purse seines ans midwater trawls. Recently, sprat catches with pound nets have been on the decline; meanwhile, use of fishing vessels, albeit more resource-consuming and dependent on the multitude of factors, can prospectively be more productive than the coastal fishing, even though currently it shows lower catches. A brief characterization of the Black Sea–Caspian sprat (tyulka) industrial fishing in the recent years is given, its trends and challenges are discussed. Daily vessel reports have been processed for 2015–2021, and the comparative data on the operation of the vessels of various types are presented; the trends in the changing industrial fishing parameters during the investigated period show a considerable decrease in all the parameters. Another crucial issue is the necessity to reduce the by-catch of non-target fish species (sturgeons, Black Sea turbot) in long-continued depressed state with midwater trawls. The presented data will allow for the current status assessment of the Black Sea–Caspian sprat (tyulka) industrial fishing and envisioning the efficient, yet selective and environmentally sound fishing methods to be developed and revised.
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Catch composition of the European anchovy (Engraulis encrasicolus L., 1758), wintering off the coast of Abkhazia in the 2021/2022 fishing seasonВодные биоресурсы и среда обитанияBased on the available data for the 2021/2022 fishing season, the ecological structure and fishing biological parameters of the European anchovy (E. encrasicolus L., 1758), wintering in the coastal waters of Abkhazia, have been analyzed. This paper presents materials that make it possible to analyze the dynamic parameters of the Azov and Black Sea stocks of the European anchovy aggregating off the coast of Abkhazia in the winter season. A comparative analysis of the main biometric parameters has been carried out. For data analysis, well-established ichthyological methods have been used. The available data on the European anchovy (both Black Sea and Azov Sea forms) caught during the investigated period characterize the dynamics of the length–age catch composition and are indicative of its intra-annual fishing patterns. Changes in the population characteristics present in the catch composition as compared with the previous years have been identified. The absolute catch values and their fluctuations are presented by the month. Analysis of the available material has indicated the main dynamic changes that characterize the wintering anchovy population as stable with a tendency for its total biomass development on a moderate level, which is not conducive for increasing the fishing effort in the next 1–2 years.
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Transformation of the polychaete taxocene in the shallow part of Karkinit Bay under conditions of changing salinityВодные биоресурсы и среда обитанияKarkinit Bay is the largest bay of the Black Sea. Since the 1960s, after the construction of the North Crimean Canal, the water in the top of the bay was heavily desalinated by runoff from fish ponds and irrigation systems. In 2014, after the canal was blocked, the salinity of the water increased, and the living conditions of the organisms changed. This work is aimed at the assessment of the change in the species composition and quantitative characteristics of the polychaete taxocene in the shallow zone of Karkinit Bay in 2018, which resulted from the changes in water salinity, as compared to those in 2008. The studies were carried out in August of 2008 and 2018—in three sampling areas at 17 stations (in 2008 and 2018 alike) at depths of 0.2–1.7 m. Samples of macrozoobenthos were collected using a manual bottom grab with a sample area of 0.04 m2. In the top part of Karkinit Bay in the first half of the 21st century, 35 species of polychaetes were recorded. Polychaete worms belonging to 19 families have been identified, with the families Phyllodocidae, Syllidae, Nereidae, and Spionidae comprising the largest number of species (4 species each). Three species — Lysidice unicornis, Polyophthalmus pictus, Syllis prolifera — were recorded in Karkinit Bay for the first time. It is shown that, with the post-2014 increase in salinity, the species richness of the polychaete taxocene in the investigated area has also increased. In 2008, 24 species were found, and in 2018, 32 species. The average abundance of polychaetes in 2008 was 948± 345 ind./m2, and in 2018, it was 417±161 ind./m2. Hediste diversicolor reached the highest abundance in 2008 (average abundance 676±371 ind./m2, maximum abundance 2313 ind./m2). In 2018, Polydora cornuta (600 ind./m2), Platynereis dumerilii (225 ind./m2), and Scolelepis tridentata (450 ind./m2) were characterized by the highest abundance. With an increase in salinity in the range of 1.5–17.8 ‰, a decrease in the density of H. diversicolor was recorded and, conversely, an increase in the density of other Polychaeta species.
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Evaluation of the tolerance threshold of marine benthic diatom Pleurosigma aestuarii (Bréb. in Kütz.) W. Smith, 1853 (Bacillariophyta) under the impact of copper (II) ionsВодные биоресурсы и среда обитанияCopper compounds accumulate in marine bottom sediments as the result of human activity and, being highly toxic, affect microphytobenthos. Evaluation of the tolerance ranges of benthic diatoms to copper pollution is important for biotesting and assessment of coastal marine environment. This work is aimed to reveal the dynamics of growth and cell death of marine benthic diatom Pleurosigma aestuarii (Bréb. in Kütz.) W. Smith, 1853 under the impact of a wide range of copper (II) ions concentrations over the course of a 10-day experiment in clonal culture, as well as to identify a tolerance threshold for this species, critical for its survival when exposed to the toxicant. The study has focused on assessment of the changes in the proportion (%) of alive cells, absolute cell number and specific growth rate of the culture at different exposure durations and concentrations of Cu2+ ions (32–1024 μg/L) and was meant to evaluate the applicability of this species as a new test object for ecotoxicology. In the control culture and in the cultures exposed to Cu2+ in the range of concentrations 32–256 μg/L, the proportion of alive cells did not change over the course of the experiment (95–99 %). At Cu2+ concentration 320 μg/L, the proportion of alive cells decreased to 23 % on the 3rd day and to 10 % on the 5th day, which provided a basis to consider this value as a threshold one for P. aestuarii survival. At Cu2+ concentrations 384 μg/L and higher, up to the maximum one (1024 μg/L), drastic inhibition of the culture was recorded as early as on the 1st day, and on the days 3–5, all the cells died. The increase in the absolute cell number in the concentration range 32–256 μg/L was consistent with the dose–response sigmoid model. Over the timespan of days 1–7, the cell number increased by 3–5 times, reaching its maximum, and then it decreased by 10–12 % by the 10th day. At Cu2+ concentrations 320 μg/L and higher, the increase in the cell number was strongly suppressed since the 1st day. Within the 32–256 μg/L range, the test culture is characterized by positive specific cell growth rate for the period up to 7 days; at the threshold concentration 320 µg/L and higher, this test parameter becomes negative. Thus, P. aestuarii should be recommended as a new appropriate test object both for toxicological experiments and for monitoring of coastal marine environment affected by technogenic pollution.
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Polychaeta taxocene in the coastal area of Lake DonuzlavВодные биоресурсы и среда обитанияThis work is based on the data collected during the benthic survey of soft sediments in the coastal area of Lake Donuzlav conducted in August, 2020. The current status of the species composition of polychaetes in Lake Donuzlav was investigated. The samples were collected using a manually operated grab sampler with a capture area of 0.04 m2 at the depths from 1 to 8 m. The following indicators were used to describe the quantitative development of benthos: abundance, biomass, occurrence, density index, and Czekanowski–Sørensen index. A total of 31 species of polychaetes have been found. The average values of polychaetes abundance and biomass in the investigated area were 239±51 ind./m2 and 1.537±0.599 g/m2, respectively. The main contribution to the total abundance is made by Spio decorata, and to the total biomass by Lagis neapolitana. The largest number of species and the highest abundance were recorded at the depths of 1.1–2 m. The largest biomass was recorded at the depths of 6.1–7 m. The ranked series according to the density index is headed by L. neapolitana, Glycera tridactyla, and S. decorata. The trophic structure of polychaetes is represented by poly-, phyto-, detritophages, carnivores, and the animals, the food spectrum of which has not been studied. The most widely represented group is carnivores; it comprises 10 species of polychaetes. The least number of species (1) was recorded for phytophages. Over 1990–2020, 73 species of polychaetes were identified; they belonged to 29 families and 56 genera.
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Specific features of spatial distribution of hydrochemical parameters in the Curonian Lagoon of the Baltic Sea in 2018–2022Водные биоресурсы и среда обитанияCuronian Bay of the Baltic Sea is a lagoon that is considered to be a water body of the highest fisheries importance. Its current geoenvironmental status is characterized by a number of problems: influx of biogenic substances from a large catchment area, algal bloom, etc. As part of the monitoring surveys of the habitat of aquatic living resources that were conducted in Russian waters of Curonian Lagoon in 2018–2022, the spatial distribution of hydrochemical parameters was investigated in 6 areas established on the basis of their morphometric and hydrological features: Teply (Warm) Bay, western, central, eastern, and southern areas, and the Neman River discharge zone. Hydrochemical conditions in Teply Bay were characterized by a considerable deviation of dissolved oxygen concentrations from the rest of Russian waters of Curonian Lagoon, as well as by the higher values of BOD5 and ammonia nitrogen, and lower values of pH and nitrate nitrogen. In the western area, the lowest content of dissolved oxygen, BOD5, ammonia, and nitrate nitrogen was recorded. In the southern area, there was a reduced content of ammonia nitrogen and nitrate nitrogen. In the central area, the values of hydrochemical parameters were close to the average ones for Russian waters. The eastern and Neman River discharge areas, exposed to significant influence of the Neman River runoff, were characterized by a high concentration of nitrate nitrogen during seasonal flood, as well as by increased values of ammonia nitrogen and BOD5 during algal bloom in summer.
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The influence of water salinity on generation of near-bottom hypoxic phenomena and the level of primary production of organic matter in Taganrog BayВодные биоресурсы и среда обитанияAt present, the Azov Sea ecosystem exists in the context of continuously decreasing continental runoff and increasing water salinity, which reached in 2020–2021 the highest values for the entire period of observations since 1962. The increase in water salinity inevitably leads to the transformation in the composition of biological communities, which has a pronounced effect on the environment and fisheries. This paper discusses the long-term impact of water salinity on the development of near-bottom hypoxic phenomena and on the volume of primary production of organic matter by phytoplankton in Taganrog Bay during the summer season (1962–2021). A statistical ecosystem analysis describing the contribution of the major hydrological and hydrochemical factors into the processes of hypoxia formation in the bottom water layer of Taganrog Bay has been performed. It is shown that the desalinization of the waters of Taganrog Bay in 1993–2008 was accompanied by the increase in the size of hypoxic zones in the bottom water layer. During the modern period of salinization extending from 2009 to the present, there has been recorded a decrease in the scale of oxygen deficiency in Taganrog Bay. The most crucial contribution to the hypoxic processes in Taganrog Bay is provided by the stability of water masses, water temperature, organic nitrogen concentration, and the water salinity (due to the effect of salinity on the stability of water masses). During the streaks of Taganrog Bay salinization, the decrease in the stability of water masses and in the content of organic nitrogen and phosphorus in the water (crucial factors in the formation of hypoxic zones) has been recorded. The highest rates of the primary production of organic matter by phytoplankton in Taganrog Bay were observed during the desalinization period of 1962–1968, and the lowest ones were recorded during the salinization periods. The results of this assessment have exposed the significant relationship: the primary production of organic matter depends on the average annual runoff of the Don River, the water salinity, and the concentration of mineral nitrogen.
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Assessment of the physicochemical properties of the main rivers of the Mekong Delta and their ecological zoningВодные биоресурсы и среда обитанияThe Mekong Delta is one of Asia's largest megadeltas. It is a region with unique biodiversity and the main food source for a large part of the population of Vietnam and Cambodia. The decrease in the biodiversity and resource capacity of the delta, associated with the growth of anthropogenic impact and other negative environmental factors, requires effort to maintain its ecosystem in a state favorable for the life of aquatic organisms, for which the first step is to organize effective monitoring of aquatic communities. Its organization must consider the complex structure of the delta and related features of the physicochemical characteristics of the habitat. The mean and interval values of the parameters were as follows: transparency was 47.7±16.4 (10–100) cm; in the surface water layer, the temperature was 29.7±1.37 (26.0–33.3) °C, electrical conductivity was 5490.4±8392.5 (133–33623) µS/cm, total dissolved solids were 3556.2±5445.8 (86.5–21853), pH was 7.6±0.3 (6.9–8.4), and dissolved oxygen was 4.8±1.05 (3.0–8.9) mg/L; in the bottom water layer, the temperature was 29.6±1.43 (26.0–34.1) °C, electrical conductivity was 7671.4±11193.2 (125–37870) µS/cm, total dissolved solids were 4905.3±7199.8 (78.0–24615.5), pH was 7.6±0.3 (6.9–8.2), and dissolved oxygen was 4.6±1.00 (2.6–7.7) mg/L. The zoning of the delta based on the knowledge of the environment makes it possible to organize the monitoring process in the most rational way. Following the results of the analysis of physicochemical parameters, the boundaries of zones with different environmental conditions that affect the formation of fish communities have been determined. The main contributing factors are salinity (3 zones), oxygen regime (3 zones), and runoff distribution (4 zones). The interrelation between the delta zoning according to the hydrochemical regime and the structural features of the fish communities at the family level has been found, which further supports the idea that such zoning must be taken into consideration when organizing monitoring surveys.
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The effect of Cayunis, EC fungicide on various links of the trophic chain in a model experimentВодные биоресурсы и среда обитанияCurrently, there is an ongoing process of development of the next-generation pesticides, which use for the purposes of agriculture has negative implications for the environment. Their hazard potential is attributable to two factors: high biological activity and their application method involving their dispersion in the environment. It necessitates the investigation of the effect of pesticides on aquatic organisms, which includes changes in their habitat, disruptions of their vital functions, especially at the early stages of their ontogeny, accumulation in their tissues, and movement along the trophic chain. Toxicological assessment of the fungicide Cayunis, EC effect has been conducted on the aquatic organisms of various taxonomic groups: microalgae (Scenedesmus guadricauda (Turpin) Brébisson, 1835), macrophytes (Elodea canadensis Michaux, 1803), molluscs (Planorbarius corneus (Linnaeus, 1758)), embryos and fry of the round goby (Neogobius melanostomus (Pallas, 1814)). Over the course of the experiment, the conditions for intoxication were identified, and the toxicometric characteristics of the aquatic organisms belonging to various trophic levels were estimated. Using an experimental approach, the threshold and no observed effect concentrations of the preparative form of Cayunis, EC pesticide have been identified for each test subject. This study made it possible to compare the sensitivity of each investigated test subject to the fungicide. Among the studied test subjects, round goby fry has proved to be the most sensitive to the effect of Cayunis, EC fungicide.
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On the 100th Anniversary of the Southern Scientific Research Institute of Marine Fisheries and Oceanography (YugNIRO). Main milestones of the Institute’s growth and research in the Azov and Black Sea Basin and the World OceanВодные биоресурсы и среда обитанияIn dedication to the 100th Anniversary of the Azov-Black Sea Research Institute for Marine Fisheries and Oceanography (AzCherNIRO), its main historical milestones and research results have been presented. On March 13, 1921, under the aegis of the regional administration of “Glavryba” (Central Administration on Fishing and Fisheries Industry of the People’s Commissariat for Food), Kerch Ichthyological Laboratory was founded, which acquired the status of an independent organization in 1922 and became the basis upon which AzCherNIRO was created in 1933, renamed into the Southern Scientific Research Institute of Marine Fisheries and Oceanography (YugNIRO) in 1988. Investigation of aquatic resources, started by the institute in the Kerch Strait, later covered the Azov Sea and the Northern and Eastern Black Sea; in 1957, they extended to ocean waters, with the Central Eastern Atlantic Ocean as their initial area. In 1960, the Ministry of Fisheries of the USSR appointed the Indian Ocean and Indian Sector of the Southern Ocean to AzCherNIRO as the survey areas in the World Ocean. From 1961 to 1990, in the course of hundreds scientific and exploratory expeditions to the Indian Ocean riparian waters, the researchers and other employees of AzCherNIRO/YugNIRO and Yugrybpromrazvedka (South Fish Exploratory Service) for the first time discovered and contributed to the production sector the aggregation sites of tropical fish and invertebrates, deepwater species at underwater ridges, and stocks of notothens, ice fishes and krill in the Antarctic. In 1970–1980, the institute maintained laboratories on stock assessment of the Black Sea and oceanic fish species and invertebrates, on fish physiology and aquaculture, on processing technology for aquatic living organisms, on commercial oceanology and industrial fishing, and many others. Currently, the scope of the Kerch Department of the Azov-Black Sea Branch of the FSBSI “VNIRO” (“AzNIIRKH”) covers the research concerning bioresources of the Azov and Black Sea Basin, World Ocean and Antarctic, processing technologies and practices, development and improvement of fishing gear, hydrobiology and aquaculture, parasitology and commercial oceanology.
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Technological standardization as a method of verification of catch volumes for sharks and rays in the Black and Azov SeasВодные биоресурсы и среда обитанияIn the fisheries industry, the output norms for the the products of aquatic bioresources processing are used to verify the actual catch volumes. Establishing of the scientifically substantiated coefficients of raw material consumption per unit of output is one of the key factors in resources exploitation. This work is aimed at technological standardization—establishment of the norms of wastes, losses and the output of processed products obtained from cartilaginous fish species caught in the Black Sea. This investigation has been targeting spiny dogfish Squalus acanthias, common stingray Dasyatis pastinaca, and thornback ray Raja clavata. Exsanguination of live cartilaginous fish immediately after it has been caught is a prerequisite of its processing. Following the research and testing on identification of wastes and losses during the processing of spiny dogfish and rays, the average output values of processed fish have been identified and the coefficients of raw material consumption have been calculated, which makes it possible, based on the volumes of processed and dressed product, to evaluate the volumes of caught cartilaginous fishes, which is especially crucial for the sharks and stingrays, extremely sensitive to fishing pressure. In has been shown that the average output values for the spiny dogfish, dressed, gutted and headed, are 44.9 %. The output values for the split carcass (wings) of stingray and thornback ray slightly differ (50.4 and 51.8 %, respectively). Statistical processing of the output values for split carcasses of the rays has shown their adherence to the law of normal distribution. Thus, it seems practical to establish a unified coefficient of raw material consumption for all rays (1.938), without the distinction between their species. The coefficient of raw material consumption for the production of gutted (exsanguinated) spiny dogfish was 1.454, and upon its further processing (beheading) it became 2.398.
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Structure and status of the European anchovy (Engraulis encrasicolus L., 1758) population, wintering off the coast of Abkhazia, in the 2020/2021 fishing seasonВодные биоресурсы и среда обитанияThis paper presents the results of analytical processing of the data collected over the course of the 2020/2021 fishing season on the ecological structure and fishing biological parameters of the European anchovy (E. encrasicolus L., 1758), wintering in the coastal waters of Abkhazia. The dynamic parameters of the Azov and Black Sea stocks of the European anchovy have also been analyzed, and a comparative analysis of the main biometric parameters has been carried out. This work is aimed at the assessment of the state of migratory anchovy aggregations in winter based on the results of the 2020/2021 fishing season and identification of the changes in the main population parameters with application of the generally accepted ichthyological methods. Following the data on the anchovy catches for the investigated period, this paper presents the dynamics of the length–age catch composition and intra-annual patterns of the anchovy fishery for the both forms (Black Sea and Azov Sea). The changes in population characteristics as evidenced from the catch composition as compared to the previous years were recorded, as well as the spatial distribution of the anchovy aggregations wintering in the Abkhazian Black Sea. The monthly absolute values are given for the catch sizes, as well as their fluctuations. The results showing the main dynamic changes in the wintering aggregations of anchovy have been obtained; they characterized the status of the anchovy population as stable with a tendency for low biomass development. It provides the basis for a conclusion that an increase in fishing effort in the next 2–3 years is unacceptable.
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Bathymetric distribution of сommon mollusc species depending on the properties of soft substrates near the coast of the Western CrimeaВодные биоресурсы и среда обитанияUp to the present day, the bathymetric distribution of zoobenthos under hydrodynamic load and subordinate changes in grain size composition and density of bottom substrate have not been fully investigated. The objectives of this study are as follows: 1) to evaluate the density of bottom sediments at different depths off the coast of the Western Crimea; 2) to calculate the pressure force exerted on substrate by the common species of bivalve molluscs (Veneridae); 3) to reveal the reasons for the changes in mollusc species composition due to differences in the properties of bottom sediments in different locations. According to the results of the underwater studies, strongly pronounced storm-induced re-sedimentation of sandy fractions is observed to the depth of 12–14 m. Sandy substrates with density of 4–8 conventional units (c. u.) are formed within this zone, and here prevails striped venus clam Chamelea gallina. These molluscs, characterized by a bulky shell (up to 30 mm) and high values of specific ground pressure (80–90 mg/mm2), can dwell near the dense sandy surface, avoiding contact with the subsurface redox layer located 6–10 cm deeper. At the depth of 16–25 m, the effect of storm hydrodynamics on the bottom weakens and only sandy aleurite fractions with density of up to 2.5 c. u. are getting re-sedimented. Sediment redox conditions develop at the depth of 4–5 cm. Within this zone, the most abundant species is rough pitar venus Pitar rudis, represented by the individuals with shells up to 13 mm in length and specific ground pressure of 35–40 mg/mm2, which allows the molluscs to stay on the surface of substrate and avoid the contact with the redox layer. At the depth of more than 27–30 m, during the storm-induced mixing processes, the sedimentation of small ground particles prevails over their horizontal transfer. In the grain size composition of the substrate, aleurite-pelitic fractions prevail, and redox layer develops deeper than 2.5 cm from the bottom surface. Only the thin surface layer consisting of loose silt with density of 0.8–1.0 c. u. remains suitable for habitation of macrozoobenthos; here, golden carpet shell Polititapes aureus, characterized by a thin shell and the lowest ground pressure (25–30 mg/mm2), prevails in terms of abundance. The results of this investigation can facilitate the understanding of spatial distribution patterns and adaptive features of the most abundant macrobenthos species under the influence of key environmental factors.
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Effect of the di(2-ethylhexyl)phthalate ester on the functional parameters of the hemolymph of the Mediterranean mussel (Mytilus galloprovincialis)Водные биоресурсы и среда обитанияDi(2-ethylhexyl)phthalate (DEHP) is the most common phthalic acid ester used in plastic matter ubiquitously polluting the World Ocean. To date, the mechanisms of the toxic effect of plastic degradation products on aquatic living organisms have been poorly studied. In this work, we investigated the effect of DEHP at various concentrations (0.4 and 4.0 mg/L) on the hemolymph cellular composition and functional parameters of the hemocytes of the Mediterranean mussel (Mytilus galloprovincialis (Lamarck, 1819)). Hemolymph samples were taken following 24- and 48-hour incubation of the molluscs in the water containing different concentrations of DEHP. Changes in the cellular composition of the mussel hemolymph and in the levels of reactive oxygen species production by hemocytes have been analyzed using flow cytometry and light microscopy. After 24 hours of experimental exposure to DEHP, an increase in the granulocyte number (from 4.0±0.5 to 38.4±7.3 %) was already observed. Additionally, a decrease in intracellular levels of reactive oxygen species (ROS) in hemocytes was recorded, and the most considerable changes occurred at the lower concentration of DEHP (0.4 mg/L). The results of this study may be indicative of a toxic effect of DEHP on the immune functions of mussel hemolymph cells.
