scholarly journals Interspecific hybridization in natural sturgeon populations of the Eastern Black Sea: the consequence of drastic population decline?

2021 ◽  
Author(s):  
Tamar Beridze ◽  
Elisa Boscari ◽  
Fleur Scheele ◽  
Tamari Edisherashvili ◽  
Cort Anderson ◽  
...  
Keyword(s):  
Interspecific Hybridization ◽  
Black Sea ◽  
Population Decline ◽  
Sharp Decrease ◽  
Mitochondrial Control Region ◽  
The Black Sea ◽  
Stellate Sturgeon ◽  
Acipenser Gueldenstaedtii ◽  
Sturgeon Species ◽  
The Status

AbstractThe eastern part of the Black Sea and its tributaries are suitable habitats for several sturgeon species, among which Acipenser gueldenstaedtii, A. stellatus, A. nudiventris, A. persicus, A. sturio, and H. huso are well documented. However, different threats have led these species to a dramatic decline, all of them are currently listed as Critically Endangered, and some Locally Extinct, in that area. We tested 94 wild sturgeon samples from the Black Sea and Rioni River by analyzing the mitochondrial Control Region and nuclear markers for hybrid identification. The data analyses (1) assessed mitochondrial diversity among samples, (2) identified their species, as well as (3) indicated instances of hybridization. The data collected, besides confirming a sharp decrease of catches of Beluga and Stellate sturgeon in recent years, also revealed four juvenile hybrids between Russian and Stellate sturgeon, providing the first evidence of natural interspecific hybridization in the Rioni. The present communication raises concerns about the status of sturgeon species in this area and underlines the urgent need for conservation programs to restore self-sustaining populations.

scholarly journals Benthic Diatom Composition in Coastal Zone of Black Sea, Sasyk Reservoir (Ukraine)

Diversity ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 458
Author(s):  
Olena P. Bilous ◽  
Agata Z. Wojtal ◽  
Natalia O. Ivanova ◽  
Petro M. Tsarenko ◽  
Olga V. Burova ◽  
...  
Keyword(s):  
Coastal Zone ◽  
Black Sea ◽  
Ecological Status ◽  
Assessment Method ◽  
Benthic Diatoms ◽  
The Black Sea ◽  
Salinity Changes ◽  
The Status ◽  
Freshwater Reservoir ◽  
First Time

The Sasyk Reservoir is one of the largest seaside reservoirs in Ukraine, artificially maintained as a freshwater area including various floodplain areas. The Reservoir originated from an estuary to now being an almost freshwater reservoir. The diatoms (Bacillariophyta) in benthos were investigated for analyzing the coastal zone diversity of the Black Sea inside the borders of Ukraine. The indicated diatom composition was formed by 97 species (100 infraspecies taxa). Some rare marine and freshwater taxa were noted, as well as three species reported in Ukrainian territory for the first time (Navicula vandamii Schoeman et R.E.M. Archibald, Sellaphora difficillima (Hustedt) C.E. Wetzel, L. Ector et D.G. Mann, and Mastogloia laterostrata Hustedt). The bioindicative characteristics of the diatom composition testified to the freshwater condition of the reservoir. Changes to the salinity level of the Sasyk Reservoir were exposed due to the composition of benthic diatoms. The presence of mesohalobous species (7 taxa) acknowledges conditions that are typical for estuaries and mouths of rivers and reveals the salinity changes in the Sasyk Reservoir. Likewise, the prevailing number of oligohalobous diatoms (61 taxa) reveal presence of freshwater in the reservoir. The implementation of the Polish phytobenthos lake assessment method for the nearby Ukrainian Reservoir was conducted for the first time. The multimetric Diatom Index for lake values varied from 0.39 to 0.76, and revealed alterations in the status over the Sasyk sites, ranging from good, moderate, to poor. Thus, it may be concluded that the current ecological status relating to the composition of benthic diatoms of the reservoir located in the coastal zone of the Black Sea is evaluated as having a moderate status class with some exceptions.

scholarly journals Rune Carvers in Military Campaigns

Viking ◽  
2021 ◽  
Vol 84 (1) ◽  
Author(s):  
Laila Kitzler Åhfeldt
Keyword(s):  
Black Sea ◽  
The Black Sea ◽  
The Status ◽  
Military Campaigns ◽  
Runic Inscriptions

Runic inscriptions, such as those found in the probable Varangian contexts of Hagia Sofia and Piraeus, as well as on the Black Sea island of Berezan, where the origin of the carver is less obvious, show that some of the Scandinavians in such contexts knew how to write runes. Domestic Scandinavian runestones also display traces of martial activities, as in the inscription about the carver Ulfr, who participated in the taking of giald in England. In addition, a number of objects inscribed with runes have been found in the Garrison at Birka. Previously, runestones have figured in debates regarding  conflict, tribute, and political expansion within Scandinavia. One of the questions that has been addressed deals with runestones in certain parts of Scandinavia – Bornholm, Gotland and Öland – and whether they were produced by locals, or by carvers from other parts of Scandinavia. Runestone characteristics that were earlier attributed to mainland Swedish influences on Gotland and Bornholm can in fact also be dependent on chronology, or be seen as regional eastern Scandinavian features. One of my queries has been whether it is possible to reach a more profound understanding of such phenomenon by analysing carving techniques, since my results indicate that some runestones on these islands were produced by travelling and visiting carvers, and could be indicators of the status of cross-regional relationships.

scholarly journals The problem of the alkalinity degree diagnostics in the soils of the northwest of the Black sea region

2017 ◽  
pp. 21-32
Author(s):  
Mykhailo Bibik ◽  
Hryhorii Moroz ◽  
Vitalii Kyrylenko ◽  
Artem Kuzmenko
Keyword(s):  
Black Sea ◽  
Final Diagnosis ◽  
Integral Approach ◽  
The Black Sea ◽  
Sodic Soils ◽  
Black Sea Region ◽  
The Status ◽  
The Moment

According to the results of the study of soils in the Northwest of the Black Sea region, it is determined that here, in the profile of vorony-calcic and calcic Chernozems, both residual and weak alkalinity are manifested. It was found out, nowadays, in the national soil science, there are no clear criteria for the selection of sodic soils and for the determination of their alkalinity degree. Furthermore, there is also the question of the differentiation of the actually sodic and residual-sodic soils. It has been established that on the territory of the Northwest of the Black Sea region polygenetic soils – vorony-calcic and calcic Chernozems weakly and residual-sodic were formed and the diagnostics of their classification and taxonomic position for the moment is rather ambiguous. The diagnostic of the alkalinity degree of vorony-calcic and calcic Chernozems in the Northwest of the Black Sea region was carried out in four methodological approaches. It was established, that it is impossible to carry out precise and unambiguous diagnostics of the alkalinity degree of soils of the territory of the study according to existing methods. Thus, the sodic and residual-sodic soils, according to classification of 1977, are almost entirely positioned as weakly sodic in accordance with the “Field determinant of soils”. In turn, taking into account the Novikova approach, the status of these same soils varies from non-sodic to solonetzes according to the degree of illuviation, the final diagnosis of which, however, contradicts the low content of exchangeable sodium. An integral approach to the determination of the alkalinity degree of soils is proposed, which is based on the chronological features of the course and direction of the sodification process. According to this approach, if the alkalinity of the studied soils is relict, its degree should be diagnosed by the illuviation of silt and by the content of exchange Na+ (Ni> 8 %, Na+<3 % – residual-sodic soils, Ni> 8 %, Na+ ≥ 3 % –sodic soils).In turn, in the case of the modern alkalinity, its degree should be determined by the ratio Ca2+/Mg2+ (<4,8) and by the content of the exchangeable Na+ (<3 % – residual-sodic soils, and ≥3 % – sodic soils). Key words: Chernozems, the alkalinity degree, diagnostic, steppe, the Northwest of the Black Sea region.

scholarly journals Crimea in the Era of Napoleon: the ‘French trace’ in regional politics

2019 ◽  
Vol 18 (3) ◽  
pp. 540-559
Author(s):  
Denis V. Konkin
Keyword(s):  
Foreign Policy ◽  
Black Sea ◽  
The Black Sea ◽  
Russian Government ◽  
Black Sea Region ◽  
Russian Territory ◽  
The Status ◽  
The Crimea ◽  
The Russian Empire ◽  
The Military

When the Crimea acquired the status of Russian territory in 1783, it became an imperial ‘borderland’ a long way from Saint Petersburg. However, in the geopolitical aspirations of European powers, and, also, from the viewpoint of the Russian Empire, the Crimea was not a remote periphery. The Russian government consistently sought to attract colonists from abroad to the thinly-populated Black Sea region. Several attempts to do so ended in failure; one of these was the organization of farming colonies at the Sea of Azov for French royalist emigrants and military men from Condé’s army. In the era of Napoleon, France paid particular attention to the peninsula; in the complicated foreign policy conditions, France did not miss any opportunity to reconnoitre the internal situation of this potentially unstable province of Russia, with the goal to infl uence the position of the Ottomans towards this territory which at that time was largely populated by Muslims. The author emphasizes that an important aspect of Napoleon’s foreign policy was supporting anti-Russian sentiment in the Ottoman Empire. One of the obvious means to achieve this goal was focusing on the Crimea issue and promising assistance for returning the peninsula into the Ottoman sphere of infl uence. The Russian authorities did not neglect these attempts and countered them skilfully. The author argues that the success of Russia’s policy in the Crimea was mainly related to certain Frenchmen in Russian service. During the Russian-Ottoman confl ict of 1806-1812, the military and administrative measures conducted by Armand de Richelieu, the Governor of New Russia, and Jean de Traversay, the commander of the Black Sea Navy, became an important factor for providing a stable situation within the peninsula.

scholarly journals Plastic Occurrence in Commercial Fish Species of the Black Sea

2021 ◽  
Vol 22 (Special Issue) ◽  
Author(s):  
Ulgen Aytan ◽  
Fatma Basak Esensoy ◽  
Yasemen Senturk ◽  
Esra Arifoglu ◽  
Kaan Karaoglu ◽  
...  
Keyword(s):  
Black Sea ◽  
Fish Species ◽  
The Black Sea ◽  
Plastic Pollution ◽  
Commercial Fish ◽  
Vital Functions ◽  
The Status ◽  
The Mean ◽  
Merlangius Merlangus ◽  
Sarda Sarda

The occurrence of micro- (<5 mm), meso- (5–25 mm) and macroplastics (>25mm) was investigated in seven commercial fish species of the Black Sea. Plastics were found in gastrointestinal track of all species analysed: Engraulis encrasicolus, Trachurus mediterraneus, Sarda sarda, Belone belone, Pomatus saltatrix, Merlangius merlangus and Mullus barbatus. A total of 352 plastic particles were removed from 190 individuals (29% of all individuals examined). The mean number of plastic particles per fish was 0.81±1.42 par.ind-1 (considering all fish analysed, n=650) and 2.06±1.09 par.ind-1 (considering only the fish that ingested plastic, n=190). The most common types of plastics were fibres (68.5%), followed by films (19%), fragments (11.9%), foams (0.3 %) and microbeads (0.3%). The most common plastic colour was black (39.3%) followed by blue (19.5%) and transparent (18.1%). The length of plastics ranged from 0.05 to 26.5 mm with an average of 1.84±2.80 mm. 93.2% of plastics were microplastics, 6.5 % as mesoplastics and 0.3% macroplastics. Plastic occurrence was higher in S. sarda (plastic in 70% of the analysed individuals) and lower in M. merlangus (plastic in 9% of the analysed individuals). The main synthetic polymers identified by Fourier-transform infrared (FTIR) spectroscopy were polypropylene (29.8%), polyester (17.5%), acrylic (15.8%), polyethylene (14%) and polystyrene (1.8%) and 21.1% of polymers were cellulosic. Results show that commercial fish of the Black Sea is contaminated by plastics. This might affect vital functions of fish and pose a risk to ecosystem and human health. The study contributes to a better understanding of the status of plastic pollution in the fish from different habitats of the Black Sea and provides baseline data to implement the Marine Strategy Framework Directive in the basin.

scholarly journals New Prey Fishes in Diet of Black Sea Bottlenose Dolphins, Tursiops truncatus (Mammalia, Cetacea)

2014 ◽  
Vol 48 (1) ◽  
pp. 83-92 ◽  
Author(s):  
E. V. Gladilina ◽  
P. E. Gol’din
Keyword(s):  
Black Sea ◽  
Tursiops Truncatus ◽  
Prey Species ◽  
Bottlenose Dolphins ◽  
Population Decline ◽  
Stomach Contents ◽  
Horse Mackerel ◽  
The Black Sea ◽  
Important Prey ◽  
Common Bottlenose Dolphin

Abstract We report 7 new prey fishes in diet of the Black Sea bottlenose dolphins Tursiops truncatus (Montagu, 1821) and the first records of 9 prey items from their stomach contents: herring (Alosa sp.), sand smelt (Atherina sp.), horse mackerel (Trachurus mediterraneus), picarel (Spicara flexuosa), Mediterranean sand eel (Gymnammodytes cicerellus), Atlantic stargazer (Uranoscopus scaber), garfish (Belone belone), gobies (Gobiidae indet.) and blennies (Blenniidae indet.). Th e Atlantic stargazer was recorded as a prey species for the common bottlenose dolphin for the first time. Th e horse mackerel and the picarel, formerly recorded in the diet of Mediterranean bottlenose dolphins, now were frequently found in the examined Black Sea dolphins. Th e list of prey fishes for Black Sea bottlenose dolphins now includes 23 items, with many small pelagic and demersal fishes, and it is similar to that of Mediterranean dolphins. Whiting (Merlangius merlangus) is still an important prey species, as 50-70 years ago, whereas turbot (Psetta maeotica), not recorded by us, could lose its importance due to population decline. As before, red mullet (Mullus barbatus) is recorded in winter feeding. Feeding on mullets (Mugilidae) is not a universal trait, and it is possibly restricted to local geographical areas.

The aquaculture of acipenseriformes. Part 5. Dunabe Basin and Middle East

2020 ◽  
pp. 69-81
Author(s):  
Igor Vladimirovich Trenkler
Keyword(s):  
Saudi Arabia ◽  
Middle East ◽  
United Arab Emirates ◽  
Black Sea ◽  
Economic Value ◽  
Arab Countries ◽  
Danube River ◽  
Danube Basin ◽  
Stellate Sturgeon ◽  
Acipenser Gueldenstaedtii

The history and contemporary state of global aquaculture of sturgeons and paddlefish are reviewed. 5th part is devoted to sturgeon breeding in the basin of Black sea (without countries of former USSR reviewed earlier) аnd in the Middle East. Six species of sturgeon once migrated in the Danube River and Turkish rivers Yeşilırmak, Kızılirmak and Sakarya for spawning: anadromous beluga Huso huso, Russian sturgeon Acipenser gueldenstaedtii, stellate sturgeon A.stellatus, European sturgeon A. sturio and the river resident ship sturgeon A. nudiventris and sterlet A. ruthenus. Sturgeons had played an important role in the history Black sea fisheries, but due to overexploitation, followed by extensive river regulations and deterioration of water quality decrease in their populations has led most of them to the verge of extinction. During the 20th Century, world demand for sturgeon meat and caviar has inflated the economic value of sturgeons so Danube basin countries and Turkey develop commercial aquaculture and conservational programs. As result of protective measures the limited natural spawning of beluga, Russian and stellate sturgeons and sterlet is preserved in Danube. In Sakarya River last spawning population of stellate sturgeon exists. These species and Siberian sturgeon are important objects of commercial aquaculture in all countries of Black sea basin. The leaders of commercial sturgeon farming in this region are Bulgaria and Israel. The sturgeon aquaculture of Hungary and Turkey developed rapidly. Saudi Arabia and United Arab Emirates are important importers of caviar. Saudi Arabia is large consumer of caviar and UAE is one of main re-exporter of caviar. Both Arab countries develop own sturgeon aquaculture.

scholarly journals An Acoustic Study on the Overwintering Black Sea Anchovy in 2020

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Ali Cemal Gücü ◽  
Batıkan Bilir ◽  
Coşkun Menderes Aydın ◽  
Murat Erbay ◽  
Savaş Kılıç
Keyword(s):  
Black Sea ◽  
Juvenile Fish ◽  
Size Composition ◽  
Distribution Patterns ◽  
The Black Sea ◽  
Adult Age ◽  
Key Species ◽  
The Status ◽  
Commercial Species ◽  
The Mediterranean

The Black Sea anchovy (Engraulis encrasicolus ponticus) is not only the top commercial species with around 250 thousand tonnes of annual catch but a key species of the Black Sea ecosystem facilitating the flow of energy within the food chain. The General Fisheries Commission for the Mediterranean has assessed the status of its stock for the Mediterranean since 2013. Underlining the shortcomings in the assessments, the commission has recommended diversifying and strengthening the data used and promote methods that provide biomass and abundance indices, such as hydroacoustics. This study aims to help fulfill the underlined deficiency by pursuing the implementation of the hydro-acoustic research surveys in the Turkish Black Sea EEZ. The survey was carried in November/December 2020, when the anchovies were accumulated within the Turkish EEZ, and cruise tracks were designed to cover the distribution areas of juvenile (0-year-old) and adult (Age 1 and over) anchovies displaying different distribution patterns within the Turkish EEZ in winter. The results show that the stock size is noticeably smaller than in previous years. Pelagic trawl sampling conducted alongside the acoustic data collection to estimate the size composition of anchovies indicated that the juvenile fish constitute an alarmingly large part of the overwintering stock.

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