Black Sea Fish Research Articles

The Danube Delta: The Achilles Heel of Danube River–Danube Delta–Black Sea Region Fish Diversity under a Black Sea Impact Scenario Due to Sea Level Rise—A Prospective Review

The Danube Delta is one of Earth’s biodiversity hotspots and includes many endemic, rare, and important species of both major conservation and economic value. This unique complex of ecosystems also plays a key role for Danube River and Black Sea fish fauna through its role as a natural safe buffer, shelter, feeding, reproduction, and smooth transitional area for a large number of fish species. Climate change is inducing a progressive sea level rise in the Black Sea, a fact that is expected to impact the delta’s key complex and dynamic habitats, biocoenoses, and associated biota, and last but not least the key taxonomic group, namely, fish. Around one-third of the fish species of this delta will be greatly affected, sometimes negatively, by this climate change scenario, another one-third to a lesser extent, and the final one-third not at all. The ecological positive feedback of fish can stimulate environmental change and is expected to be responsible for changes within Danube Delta ecosystems, and also for the near Danube River and Black Sea diverse matrix of aquatic and semi-aquatic ecosystems. Sea level rise in the Black Sea is considered to have been one of the main stress factors of the Danube Delta fish fauna in the past, and is likely to be the case in the future. In this spatio-temporal dynamic context, for the fish species under threat and risk, in situ-adapted management measures are highly required. The current work brings for the first time such a prospective knowledge about the potential impact on Danube River–Danube Delta–Black Sea coast fish diversity in the potential climate change–sea level rise scenario.

Greek and Roman Marine Resource Exploitation in the Northern Black Sea: The Origin and Dynamics of the Bosporan Fish Trade

As early as the fifth century BC salted fish were exported from the Black Sea to the cities of the Mediterranean. From the beginning of our era, Pontic fish-salters also produced garum, a sauce made from fermented fish. At some sites, production of salted fish and sauce continued well into the Byzantine period. The evidence for Pontic fish processing is somewhat contradictory. On the one hand, literary texts such as the Deipnosophistae of Athenaeus (c. AD 200) attest to the importance of Black Sea salt-fish in the Mediterranean market, while finds of large-scale salting installations at several sites in the Crimea testify to the large volumes of fish that were processed into garum or salt-fish. On the other hand, finds of amphorae for the finished product are rare. Finds of Black Sea amphorae reported from sites along the Mediterranean by no means match the massive numbers of fish amphorae from the Iberian Peninsula which have been found on Roman sites. Taking imports rather than exports as its starting point, this paper proposes a new model for the development and organization of fish exports from the Black Sea. The export trade was not primarily driven by the Aegean demand for processed fish, but by the demand for prestige goods among the Pontic elite. Exports generated the cash income required for the elite’s consumption of imported prestige commodities such as oil and wine. As the supply of another export commodity – slaves – declined under the pax Romana, the volume of fish exports was increased. It is also proposed that fish products were not as a rule exported by the producers themselves. Rather, they were acquired in bulk at the production site by travelling wholesalers, who packed them in empty amphorae brought from the Mediterranean; hence traces of the Black Sea fish trade are almost invisible in the archaeological record.

A study of the microbiology of the intestinal tract in different species of Teleost fish from the Black Sea

This paper presents a study on the microbial status of different fish species and their habitats in the Bulgarian Black Sea area. The samples were collected in the period of January 2021 until March 2021. The fish species we used in this study were Black Sea turbot (Scophthalmus maximus), round goby (Neogobius melanostomus), shore rockling (Gaidropsarus mediterraneus) and European anchovy (Engraulis encrasicolus). The BIOLOG system was used for microbiological determination. From the different fish species, different species of microorganisms were isolated (using selective nutrient media). From the torbut, we isolated species Enterococcus villorum with 24 × 103 cells in 1 ml, Moraxella nonliquefaciens with 70 × 103 cells in 1 ml and Pseudomonas synxantha with 123 × 103 cells. Pseudomonas putida was isolated from the round goby with 20 × 103 cells in 1 ml. The species Streptococcus entericus with 123 × 103 cells in 1 ml was isolated from the shore rockling. Pseudomonas fulva with 60 × 103 cells in 1 ml was isolated from the European anchovy. A total of 223 × 103 cells in 1 ml of Pseudomonas agarici were isolated from Trachinus draco. Pseudomonas tolaasii with 145 × 103 cells in 1 ml were isolated from Merlangius merlangus. A different species of bacteria of the genus Pseudomonas was found for each of the investigated species of Black Sea fish. Apparently, the species Pseudomonas is characteristic of marine Teleostei and is important for the life and metabolism of these vertebrates. These microorganisms probably are resident species and developed not as result of pollution or environmental change.

Element concentrations of cultured fish in the Black Sea: selenium-mercury balance and the risk assessments for consumer health.

Fish are a powerful model for risk-benefit analyses to explore the impact of elements on human health among all accessible species. The sea bream (Sparus aurata), sea bass (Dicentrarchus labrax), turbot (Scophthalmus maximus), and weights of > 1kg large rainbow trout registered as "Turkish Salmon," (Oncorhynchus mykiss) are four economically important cultured species in the Black Sea In this research, it is aimed (1) to determine the value of the elements, (2) to determine total Hg and Se concentrations, Se/Hg molar ratios, and the HBVSe index, and (3) to calculate the consumer's possible health risk in the edible tissues of cultivated four economically important Black Sea fish species. Fish and diet samples from all species were obtained in 2020 from aquaculture locations in the Black Sea (Sinop, Samsun, and Trabzon cites of Turkey). At the end of the study, the elements in all edible tissues and all the parameters analyzed [Se/Hg, estimated daily intake (EDI), target hazard quotient (THQ), maximum allowable consumption rate (CRlim and CRmm)] in cultured fish tissues were below permissible values. Additionally, when compared with the data of the World Health Organization and The National Academy of Sciences, it determined that consuming cultured fish in the Black Sea adequately meets the daily elemental requirement.

Эйдономия и внутривидовая изменчивость морского ерша Scorpaena porcus Linnaeus, 1758 (Pisces: Scorpaenidae) кавказского шельфа российского сектора Черного моря

There are only fragmentary data on the intraspecific limitation of the black scorpionfish Scorpaena porcus Linnaeus, 1758 in scientific literature. The black scorpionfish is a background fish species attracted to the use of Black Sea fish community.The purpose of this work was to study the eidonomy of the black scorpionfish from the Caucasian shelf of the Black Sea, as a full-fledged study of its intraspecific variability.The morphological (plastic and meristic) parameters of black scorpionfish from three water areas of the Caucasian shelf of the Black Sea are compare in this paper. Samples from coastal waters in the areas of Bolshoi Utrish, Magri and Adler were studied in this paper. It is shown that the black scorpionfish of the water areas under consideration have very different sets of morphological features, which can be used to successfully distinguish representatives of different regions from each other.

Habitat suitability models of five keynote Bulgarian Black Sea fish species relative to specific abiotic and biotic factors

Over the past few years, predicting species spatial distributions has been recognized as a powerful tool for studying biological invasions in conservation biology and planning, ecology, and evolutionary biology. Species spatial distribution models (SDMs) are used extensively for assessing the effects of changes in habitat suitability, the impacts of climate change, and the realignment of the existing conservation priorities. SDMs relate known patterns of species occurrences to a specific set of environmental conditions. Accordingly, we have used MaxEnt SDM tool in order to provide habitat suitability models of 5 keynote fish species: European sprat (Sprattus sprattus L.), red mullet (Mullus barbatus, L.), horse mackerel (Trachurus mediterraneus, L.), bluefish (Pomatomus saltatrix, L.) and whiting (Merlangius merlangus, L.), inhabiting the Bulgarian region of the Black Sea. Presence-only (PO) data collected by pelagic surveys performed between 2017 and 2019 was further utilized to link known species occurrence localities with selected abiotic factors, such as surface sea temperature and salinity, dissolved oxygen, and speed of currents. Biotic interactions were also considered for fitting the patterns of habitat suitability models. The SDMs, obtained from the present research study, prove to have satisfactory predictive accuracy to be further implemented for conservation measures and planning, stock management policy-making, or ecological forecasting.

Variability in the number of rays and specification of the dorsal fin formula of the black scorpionfish Scorpaena porcus Linnaeus, 1758 (Pisces: Scorpaenidae) from the Black Sea

Out of the morphological criteria for the fish species, the meristic (countable) characters are of the key role, in particular the number of rays in the fins. It is one of the stable signs of fish morphotype not subjected to size and age variability. At the same time, it is a clear taxonomic criterion. The aim of the work was to study the variability in the number of rays in the dorsal fin and to specify its formula for the black scorpionfish inhabiting the Black Sea off the coasts of the North Caucasus and Crimea. In total, 232 individuals of the black scorpionfish were investigated; those were sampled from six areas of the Black Sea off the coasts of the North Caucasus (Bolshoi Utrish, Magri, Loo, and Adler) and Crimea (Sevastopol and Feodosiya). The number of rays in the dorsal fin of each fish was counted, with dividing them into hard (unbranched) and soft (branched) ones. As established, the total number of rays in the dorsal fin of the black scorpionfish inhabiting the coasts of the North Caucasus and Crimea averaged (22.1 ± 0.02); the number of hard rays, (12.0 ± 0.01); and the number of soft rays, (10.1 ± 0.03). All three indicators are characterized by low variability (coefficient of variation is lower than 10 %). Fish caught off the coasts of the North Caucasus and Crimea differ statistically significantly from each other in the number of soft rays in the dorsal fin [(10.1 ± 0.03) and (10.0 ± 0.04), respectively] and in the total number of rays in the dorsal fin [(22.1 ± 0.03) and (22.0 ± 0.04), respectively]. The analysis of the results obtained reveals six possible variants of the dorsal fin formula for the black scorpionfish. Those are: D XI 10; D XI 11; D XII 9; D XII 10; D XII 11; and D XIII 10. The most common variant is D XII 10 averaging 83.2 % (75.0–88.9 % depending on the area). The updated dorsal fin formula for the black scorpionfish inhabiting the coasts of the North Caucasus and Crimea has the following form: D (XI) XII (XIII) (9) 10 (11). The formula can be used when compiling the species guides of the Black Sea fish. The results obtained were compared with those of other researchers. The causes for the disagreement between the results were analyzed.

Occurrence of Dusky Grouper Epinephelus marginatus (Lowe, 1834) from the Black Sea: Is it the Mediterranization Process of the Black Sea?

A single specimen of Dusky Grouper Epinephelus marginatus (Lowe, 1834) on 14 November 2021 at a depth of about 10 m from the southwestern Black Sea (Amasra, Turkey) was captured by a fisherman with fishnet. In this study, dusky grouper Epinephelus marginatus was recorded for the first time from the Black Sea as a new Mediterranean species for the Black Sea fish fauna.

Can Fish and Shellfish Species from the Black Sea Supply Health Beneficial Amounts of Bioactive Fatty Acids?

Fatty acids (FA) are among the most important natural biologically active compounds. A healthy diet involves the intake of different fatty acids especially from omega-3 (n-3) series. Seafood provides a very good source of polyunsaturated fatty acids (PUFAs), but in Bulgaria there is limited information regarding the n-3 PUFA contents in traditionally consumed seafood by the population. The aims of this study were to determine lipid content, omega-3 polyunsaturated fatty acids (EPA and DHA), and the recommended daily intake of eleven fish species, three bivalves, rapana, and shrimp harvested in the Western part of Black Sea, Bulgaria. Total lipids were extracted according to the method of Blight and Dyer and fatty acid composition was analyzed by GC/MS. Fatty acid profile showed differences among species. PUFA were found in high content among total lipids, especially in shellfish (60.67–68.9% of total lipids) compared to fish species (19.27–34.86% of total lipids). EPA was found in higher amounts in rapana (0.16 g/100 g ww) and two of pelagic species (up to 0.29 g/100 g ww), whereas DHA prevailed in demersal and the most of pelagic fish (0.16–1.92 g/100 g ww) and bivalves (0.16–1.92 g/100 g ww). The health beneficial n3/n6 and PUFA/SFA ratios were found in all analyzed species. The lower values of the lipid nutritional quality indices (AI < 1, TI < 1) and higher for h/H index (0.8–1.78 for fish and 1.52 to 4.67 for bivalves and shrimp) confirm that the commonly consumed Black Sea fish and shellfish may provide health benefits for local populations. This study shows the seafood amounts that can provide the minimum recommended intake of omega-3 polyunsaturated fatty acids.

Fishing under climate change: Dynamics of composition and structure of catches in the Russian Black Sea in the XXI century

Currently, the Black Sea ecosystem is undergoing significant changes, and that affects the dynamics of the species composition of catches. The main reasons for the change in the Black Sea ichthyofauna are considered to be: fishing, anthropogenic water pollution, invasion of new species, and the effect of large-scale climatic and related oceanological and hydrological processes on the productivity characteristics of commercial Black Sea fish. With no understanding the patterns of the effect of these factors on ichthyofauna, it is impossible to rationally use bioresources and protect nature. The aim of the work was to study the effect of climate warming on the species composition and structure of catches in the Russian Black Sea in the XXI century. The authors had used: the results of own ichthyological observations; data published on the composition of the Black Sea catches; and the information available on the official websites of the Ministry of Agriculture of the Russian Federation, the Federal Agency for Fishery, and its Sea of Azov – Black Sea Territorial Administration. The analysis of the possible effect of global warming on the results of fishing in the Russian Black Sea was carried out. It is shown that in the XXI century, the ratio of thermophilic fish, which spawn in the summer, increased; those species are European anchovy Engraulis encrasicolus (Linnaeus, 1758), red mullet Mullus barbatus Linnaeus, 1758, and horse mackerel Trachurus mediterraneus (Steindachner, 1868). As established, the dynamics of the ichthyofauna in the area is determined by at least four processes related to water warming: improvement of reproduction conditions and increased survival of eggs and juveniles of thermophilic species; change in the intraspecific structure; invasion and naturalization of Mediterranean species with the subsequent change in the food relationships within the ecosystem; and concentration of psychrophilic species at greater depths. The need for a thorough study of this issue is concluded, aimed at long-term forecasting of the raw material base state of the fishing industry in the Russian Black Sea.

Сравнительная характеристика ультраструктуры клеток нефрона некоторых видов пелагических, придонных и донных рыб (бухта Карантинная, Чёрное море)

Изучена ультраструктура основных отделов нефрона мезонефроса костистых рыб Чёрного моря (пелагических Trachurus mediterraneus (Steindachner, 1868) и Chelon auratus (Risso, 1810); придонных Diplodus annularis (Linnaeus, 1758) и Spicara flexuosa Rafinesque, 1810; донных Scorpaena porcus Linnaeus, 1758, Gobius niger Linnaeus, 1758 и Mullus barbatus ponticus Essipov, 1927). Показано, что у рыб Чёрного моря, обитающих на разных глубинах и находящихся в различных условиях осмотической нагрузки среды, на тканевом уровне организации нефроны имеют единый план строения и формируют гломерулярные почки. Приспособленность рыб к обитанию на определённых глубинах в первую очередь проявляется в увеличении количества и размеров митохондрий всех типов эпителиальных клеток нефрона. Кроме того, отмечено уменьшение площади почечных телец, длины подоцитов и высоты эпителиоцитов канальцев, а также длины щёточной каёмки проксимальных канальцев I типа. Цитологические особенности нефрона пелагических, придонных и донных рыб характеризуют высокую адаптационную способность клеточных структур мезонефроса.

Variability of the hepatic α-amilase activities in the liver of fish species from the Sevastopol bays, Black Sea

This paper presents the results of a study of α-amylase activity in liver of widely represented species of twelve Black sea fish. Comparative analysis of interspecies differences showed that the medium level of enzyme activity is very high only in liver of annular seabream and horse mackerel. The Black Sea predators (scorpion fish, stargazer, shore rockling, whiting) have low values of the medium level of enzyme activity (range from 0,02 to 62,79 mg / s / g of protein). Enzyme activity did not depend on fish sex, their age and location. Research has established lack of any link between activity of enzyme and age for both the scorpion fish and high body pickarel. While studying the effects of seasonal features on enzyme activity in the liver of two dominant species in the coastal zone, it was concluded that enzyme activity is lower in winter than in other seasons.

Characterization of Some Hepatic Biochemical Indicators in Three Demersal Black Sea Fish Species

A comparative analysis of hepatic biochemical indicators in three demersal Black Sea fish species—scorpionfish Scorpaena porcus (Linnaeus, 1758), round goby Neogobius melanostomus (Pallas, 1814) and knout goby Mesogobius batrachocephalus (Pallas 1814)—was carried out. The interspecific differences between the indicators of the prooxidant-antioxidant system (activity of antioxidant enzymes, lipid peroxidation and oxidized proteins) and other liver biomarkers (aminotransferase and alkaline phosphatase activities, triglyceride levels) were analyzed. The reasons for the revealed changes are discussed.

Interspecies Peculiarities of Some Enzyme Activities in the Gonads of Black Sea Fish

Significant interspecies differences were established in activities of aminotransferases, alanine aminotransferase (ALT, EC 2.6.1.2) and aspartate aminotransferase (AST, EC 2.6.1.1), and alkaline phosphatase (ALP, EC 3.1.3.1) in the gonads of seven Black Sea fish species during spawning and non-spawning seasons. In most species, ALT and AST activities were higher in the non-spawning phase compared to the spawning one, while ALP activity demonstrated an opposite trend. The peak enzymatic activities were found in the gonads of the whiting, probably due to its spawning in the winter season. No significant differences were revealed between the test parameters in animals of different ecological groups. ALT, AST and ALP activities in fish gonads can be used as convenient and efficient markers to explore both the peculiarities of the gonadogenesis at different stages of the reproductive cycle and the ability of different fish species to adapt to unfavorable environments, including those caused by anthropogenic pollution.

Validation of a Quantitative Analysis Method for Collagen Extracted from Grey Mullet Marine Fish

The Black Sea offers numerous harnessing possibilities for the medical and pharmaceutical, agricultural, food industry and cosmetic fields. Collagen extraction from the Black Sea fish is a research area of great interest. The purpose of this paper is to optimize the collagen quantitative analysis method based on hydroxyproline reagent through visible molecular absorption spectrometry. The adapted method was validated, achieving the following performance criteria: linearity, detection and quantification limits, accuracy/fidelity, stability/sturdiness, repeatability, and measurement uncertainty. The validated method was applied for the quantitative determination of collagen content in Grey Mullet fish and for the evaluation of collagen extraction output.

Study of Dimensional and Morphological Characteristics of Erythrocytes in Some Black Sea Fish of Different Evolution Position and Ecological Specialization

A comparative analysis of the morphometric parameters of erythrocytes in two species of cartilage (Chondrichthyes) and five species of teleosts (Teleostei) Black Sea fish of different natural mobility was carried out. The volume, area, and shape index of the cell and nucleus, the specific surface and useful volume of the cell, and the nuclear-cytoplasmic ratio are calculated based on the linear dimensions of the cell and the nucleus. It has been shown that the studied cartilaginous fish (rays) had larger erythrocytes compared with the teleosts: the linear dimensions are 2–3 times larger, and the volume is 7–30 times larger. In actively swimming teleosts, the volume of erythrocytes and their nuclei is smaller than those of slow-moving species (2–3 times and 5–9 times, respectively). The revealed differences in the erythrocytes’ morphometric characteristics of cartilaginous and teleosts are considered to reflect the direction of the evolutionary process towards increasing the energy potential of the circulatory system of the “younger” fast-swimming teleosts.

Studies of mezozooplankton in the Zmiinyi Island coastal waters in 2016-2017

Purpose. To study the state of mezozooplankton in the Zmiinyi Island coastal waters in 2016-2017. Methods. Standard methods of mezozooplankton sampling, determination, number and biomass assessment. Results. Based on the data received, analysis of biodiversity and structural characteristics of mezozooplankton in the Zmiinyi Island coastal waters has been made. Taxonomic composition, number and biomass have been determined for each species; dynamics of number and biomass presented season by season. Marine environment quality assessment has been performed on the metrics of mezozooplankton. Conclusions. Altogether 32 taxa of 9 main mezozooplankton groups were identified in 2016-2017. It was shown that the dominating groups were Copepoda, Rotatoria, Protozoa, Cladocera and Harpacticoida. Shannon’s biodiversity index of mezozooplankton varied from 0.41 (20.06.2016) to 3.29 (24.07.2016) with average values 2.32 in 2016 and 1.64 in 2017. Mezozooplankton number and biomass varied in 2016-2017 within broad limits from 645 to 55829 ind/m³ and 1.385 to 2597.248 mg/m³ respectively (with average values 10129 ind/m³ and 154.82 mg/m³ in the period IV-XII, 2016 and 21563 ind/m³ and 466.30 mg/m³ in the period IV-VI, 2017). Water quality in the coastal waters of the Zmiinyi Island on the state of mezozooplankton was «Bad» in 18 cases out of 68 (26.4%) and was assessed in general as «Poor». On total mezozooplankton biomass the state was assessed as «Poor» and «Bad» (68.2%). «Good» (10.6%) and «High» (9.1%) quality was found in 19.7% of cases, which evidenced unsatisfactory state of mezozooplankton – the main component of food reserve for pelagic larvae and pelagic species of the Black Sea fish.

Black Sea fish and shellfish as essential source of vitamin B12

&lt;p class="abstract"&gt;&lt;strong&gt;Background:&lt;/strong&gt; Vitamins are very important for the human body because they are necessary for many biological absorption processes of other nutrients, for cells and tissues growth and repair. Because of this, there are many recommendations on daily vitamins intake, approved by the different country and world food organizations. Usually under the term "vitamin B&lt;sub&gt;12&lt;/sub&gt;" is understood only cyanocobalamin, but actually this name is general and covers all potentially biologically active "cobalamins"- a group of cobalt-containing compounds. Animal foods, as different meat, milk, eggs, fish and shellfish are considered as the main dietary sources of this vitamin. They contain different forms (methylcobalamin and deoxyadenosylcobalamin) of vitamin B&lt;sub&gt;12&lt;/sub&gt; in different amounts. There is limited information in the scientific literature about the vitamin B&lt;sub&gt;12&lt;/sub&gt; content in black sea fish and shellfish. The aims of the present work were to determine and compare vitamin B&lt;sub&gt;12&lt;/sub&gt; contents as well as relative daily intake of vitamins in different fish and shellfish species from Black Sea waters.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Methods:&lt;/strong&gt; Vitamin B&lt;sub&gt;12&lt;/sub&gt; was analysed spectrophotometrically. The method for quantitative analysis includes extraction from the edible tissue and enzymatic hydrolysis to release the cobalt ions. &lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Results:&lt;/strong&gt; The quantities of vitamin B&lt;sub&gt;12&lt;/sub&gt; found in the edible tissue of the analysed samples ranged from 0.63 μg.100 g&lt;sup&gt;-1&lt;/sup&gt; ww to 21.5 μg.100 g&lt;sup&gt;-1&lt;/sup&gt; ww.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Conclusions:&lt;/strong&gt; The observed results confirm that all fish and molluscs samples deliver significant quantities of the water-soluble vitamin B&lt;sub&gt;12&lt;/sub&gt;.&lt;/p&gt;&lt;p&gt; &lt;/p&gt;

Первые данные генотипирования черноморских трематод родов Cainocreadium и Helicometra (Trematoda: Opecoelidae)

Впервые изучены нуклеотидные последовательности ITS1 кластера генов рРНК марит черноморских трематод Cainocreadium flesi Korniychuk &amp; Gaevskaya, 2000 от камбалы глоссы Platichthys flesus (депонированы в GenBank с номерами MG980645, MG980646), Cainocreadium sp. от морского налима Gaidropsarus mediterraneus (MG980643, MG980644, MK248037, MK248038) и Helicometra fasciata (Rud., 1819) от собачки-павлина Salaria pavo (MG980647, MG980648). ITS1-последовательности черноморских трематод C. flesi и Cainocreadium sp. оказались идентичными, однако, ввиду морфологических отличий между этими гостальными морфами, видовой статус трематод от морского налима пока не определён. По четырём позициям ITS1-последовательности черноморских Cainocreadium отличались от аналогичных последовательностей, описанных у церкарий близкородственного средиземноморского вида, C. labracis. Пять инсерций-делеций и 38 нуклеотидных замен отличают ITS1-последовательности черноморских Cainocreadium от аналогичных последовательностей представителей ещё одного средиземноморского вида этого рода, C. dentecis. ITS1-последовательности черноморских и средиземноморских образцов H. fasciata также различаются: выявлено пять нуклеотидных замен и 11 инсерций-делеций.

Evolution of Future Black Sea Fish Stocks under Changing Environmental and Climatic Conditions

Here we present a case study towards producing quantitative scientific advice on the application of the EU Common Fisheries Policy (CFP) in the Black Sea. We provide estimates of fishing mortality rates at levels which will lead to rebuilding and maintaining stocks above biomass levels that could produce maximum sustainable yield (MSY) under the IPCC RCP4.5 future climate scenario together with the business as usual (BAU) river discharge scenario. In this study, we have implemented a coupled, basin-scale circulation-biogeochemical model and used its output to feed a food web model to test near-future changes that may be observed in the Black Sea ecosystem under the influence of contemporary fisheries exploitation conditions. In order to test model response to changes in climate and related drivers, the future climate scenario (2015-2020) simulation was compared to the present day (2000-2014) simulation. Likewise, to test the sensitivity of the higher trophic level food web model to changes in fishing pressure, a future estimate of fishing pressure was projected based on its respective contemporary value and applied to each fish stock. Using these models, fishing mortality rates that could produce the maximum sustainable yield (FMSY) in future years 2015-2020 and ensure the long-term recovery of the predatory fish stocks of the Black Sea are predicted. Future projections suggest that all fish stock will decrease in all the regions of the Black Sea except for sprat. Anchovy is expected to show the highest decrease in biomass. Analyses on FMSY estimates show that a significant reduction in fisheries exploitation is required for the sustainable management of the Black Sea ecosystems and the related services. This study, for the first time, presents future stock size, FMSY and MSY estimates for the Black Sea for 11 fish species. FMSY values are generally lower than estimates of the scientific, technical and economic committee for fisheries (STECF), mainly because of the explicit food web interactions that the modeling system allows to be considered.