Marine Biological Journal最新文献

{"title":"Toxic metals in the warty crab in the southern Black Sea: Assessment of human health risk","authors":"L. Bat, E. Arıcı, Ayşah Öztekin, F. Şahin","doi":"10.21072/mbj.2020.05.1.01","DOIUrl":"https://doi.org/10.21072/mbj.2020.05.1.01","url":null,"abstract":"The present study was performed to assess Cd, Pb, and Hg contaminations and human health risk in the warty crab Eriphia verrucosa (Forskål, 1775) in Akliman shores of Sinop Peninsula of the Black Sea. Heavy metals analysis was performed by inductively coupled plasma mass spectrometry. Among studied toxic metals, Pb had the highest mean concentration in E. verrucosa. The highest mean concentration of Pb (0.2 mg per kg of wet weight) was observed in male samples of the warty crab. However, higher concentrations of Cd and Hg (0.11 and 0.019 mg per kg of wet weight, respectively) were observed in females of E. verrucosa. The mean Cd values found in the warty crabs were higher in May and June than those in July and August. On the other hand, Pb values were recorded in July and August. The mean Hg values were not different between months except July and August for male samples of E. verrucosa. Foraging seasons of these crabs are different, which can lead to differences in prey size and ultimately metals intake. However, the results show that a toxic heavy metal concentration in edible tissues of crab from the southern Black Sea was within the permissible limits given by national and international food codices. Target hazard quotient (THQ) for each metal and hazard index (HI) were calculated to evaluate non-carcinogenic human health risks. Estimated THQs of Cd, Pb, and Hg suggest that these metals in the warty crab do not pose any apparent threat to humans, when the HI value is below the value of 1. The result of the analysis has shown that the warty crab E. verrucosa can be used as bioindicator as it contains variable levels of the metals observed. Since consumption is the main source of heavy metal intake by humans, monitoring studies are needed to protect public health and take preventive measures.","PeriodicalId":18191,"journal":{"name":"Marine Biological Journal","volume":"14 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86666356","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"History of formation and peculiarities of Ponto-Caspian fish myxosporean fauna","authors":"V. Yurakhno, A. Özer","doi":"10.21072/mbj.2020.05.1.10","DOIUrl":"https://doi.org/10.21072/mbj.2020.05.1.10","url":null,"abstract":"History of formation of Ponto-Caspian basin fish myxosporean fauna is examined. This work is based on our own material on myxosporean parasites of fish from the Black Sea (collected in 1987–2018) and the Sea of Azov (1997–2016). Totally, we have investigated 15 368 specimens of 87 species of fish (14 297 specimens of 80 species of fish in the Black Sea and 1071 specimens of 19 species of fish in the Sea of Azov). The material was collected by the method of incomplete parasitological dissections and treated by generally accepted methods. Also, all available literary sources on the myxosporean parasites of fish from the Black Sea, the Sea of Azov, and the Caspian Sea are analyzed (references list contains the most significant publications). A comparative analysis of fish myxosporean fauna in the Black Sea, the Sea of Azov, and the Caspian Sea is performed. It is stated that 108 parasite species are known in the Black Sea, 42 – in the Sea of Azov, and 68 – in the Caspian Sea. Number of myxosporean parasite species common for the Sea of Azov and the Black Sea is 32, for the Caspian and Black seas – 32, and for the Sea of Azov and the Caspian Sea – 20. Totally 16 species of myxosporean parasites are registered in all the mentioned seas. To date, of 108 myxosporean species of Black Sea region, 29 are registered only in freshwater fish in the estuaries with considerable brackish water. For 79 myxosporean species, marine fish species serve as hosts; they are registered mainly in full-salt sea part, and 17 of them are of freshwater origin: 7 species are registered in freshwater fish and in euryhaline mullets; 1 parasitizes on freshwater and marine salmon fishes; the only hosts for 9 species are mullets or other marine fish species. Marine forms are represented by Pontic (22 species), Ponto-Azov (3), and Ponto-Caspian (2) endemics, as well as by Mediterranean invaders (35). Among freshwater myxosporeans, only 1 species is Black Sea endemic; 1 species is Ponto-Azov endemic, and most other species are widely represented in freshwater reservoirs. Among Mediterranean invaders, 23 species found in the Mediterranean Sea should be noted; 12 species still have not been registered in the Mediterranean Sea, mainly due to very few studies on this group of parasites. The fauna of Sea of Azov fish parasites includes 42 myxosporean species; 32 of them are found in the Black Sea, 20 – in the Caspian Sea. Totally 19 species belong to freshwater ones, and they are parasitic only in freshwater fish species. Ten species are of freshwater origin but can be registered in marine fish species (mostly in mullets, and one – in gobies). Of the freshwater species, one is Ponto-Azov endemic. Totally 13 myxosporean species are marine ones: 2 species are Sea of Azov endemics; 3 species are Ponto-Azov endemics; 8 species are Mediterranean invaders. Caspian Sea fauna includes 68 species of myxosporeans: 8 are marine ones (1 is ancient marine species; 1 is Ponto-Caspian endemic; 6 are bra","PeriodicalId":18191,"journal":{"name":"Marine Biological Journal","volume":"65 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84580800","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantitative relationship between solar radiation intensity and average daily value of photosynthesis light saturation for phytoplankton in the deep-water area of the Black Sea","authors":"I. V. Kovalyova","doi":"10.21072/mbj.2020.05.1.05","DOIUrl":"https://doi.org/10.21072/mbj.2020.05.1.05","url":null,"abstract":"According to data obtained during expeditions in the Black Sea (1987–1993), linear relationship between the light flux density incident on the sea surface (E0) and the starting point of photosynthesis light saturation (En opt) is revealed. For calculations, measurements of phytoplankton photosynthesis rate obtained by the radiocarbon method were used. The equation of the relationship between the values reported is presented for the first time for the Black Sea. En opt is the average daily, optimal value of photosynthesis light saturation. The parameters of photosynthesis – light curve, determined in short-period exposures under constant illumination, differ from the parameters obtained in long-term experiments under conditions of variable illumination. This is due to different effects of the intensity and dose on the phytoplankton photosynthesis rate. The values of photosynthetic parameters for a certain time are integrated into a single value which is the optimum for the entire period observed. The approximation of daily data integrated is carried out both separately for seasons and in general for the period of 1987–1993. Using statistical processing of data of average daily values of the intensity of solar radiation incident on the sea surface, slope of the photosynthesis – light curve, and maximum photosynthesis rate, the approximation is determined for the functional dependence of En opt on E0. The equation is applicable in the range of light intensity 3 to 75 mol quanta·m−2·day−1. It describes with high reliability a change of average daily value of photosynthesis light saturation in the Black Sea during different seasons of the year. The equation includes a parameter easily accessible for measurement. It can be used in analysis of physiological characteristics of phytoplankton and calculation of integrated phytoplankton productivity in euphotic layer with using both satellite and expedition data.","PeriodicalId":18191,"journal":{"name":"Marine Biological Journal","volume":"111 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84917765","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fish cestodes of the Karadag nature reserve and adjacent water areas of the Black Sea","authors":"T. Polyakova","doi":"10.21072/mbj.2020.05.1.06","DOIUrl":"https://doi.org/10.21072/mbj.2020.05.1.06","url":null,"abstract":"The first data on marine fish parasites in Karadag nature reserve water area were published at the beginning of the 20th century. By the beginning of the 21st century, information on the fauna of cestodes in this area of the Black Sea included data on 19 species recorded in 24 fish species. However, taxonomy of this class of helminths has changed significantly over the last decade, and regional fauna needs to be revised. The aim of this work is to revise the species composition of fish cestodes in the water area of the Karadag nature reserve and adjacent areas on the basis of new data obtained and in accordance with current systematics of Cestoda. The material for this study was the collections of cestodes gathered by the staff of IBSS RAS Environmental Parasitology Department in the area of the Karadag nature reserve in different years, as well as our own collections of 1754 specimens of rays and teleosts of 53 species (2005–2018). The area studied is Black Sea coastal area from Meganom Cape to Ordzhonikidze village (southeastern part of Crimea), including various marine biotopes of the Karadag nature reserve. Voucher preparations of all types of cestodes used in this study were deposited in a subcollection of marine parasites of the World Ocean hydrobionts collection of IBSS RAS. Totally 20 cestode species were found in 17 fish species. Nine species, namely Progrillotia dasyatidis, Parachristianella trygonis, Dollfusiella aculeata, Rhinebothrium walga, Caulobothrium sp., Rhabdotobothrium sp., Acanthobothrium sp. 5, 7, and Anthocephaliidae gen. sp. 2., were reported for the common stingray Dasyatis pastinaca in the area under study for the first time. Cestodes belonging to the new species Acanthobothrium sp. 1, 2, 4 were found in the thornback ray Raja clavata. Of 19 species previously known in Karadag area, only 8 adult mature cestodes were recorded: “Bothriocephalus scorpii”, “B. gregarius”, Echinobothrium typus, Grillotia erinaceus, Prochristianella papillifer, Echeneibothrium variabile, Cairaeanthus ruhnkei, and C. healyae. In addition, larvae of the complex species “Scolex pleuronectis” were found in teleost fish. Larvae of cestode Progrillotia dasyatidis were found for the first time in the water area studied in 8 teleost fish species; this data contribute to the information on the participants in the life cycle of this helminth. Four cestode species, namely Hepatoxylon trichiuri larvae, Nybelinia lingualis larvae, Tetrarhynchobothrium tenuicolle, and Anthobothrium cornucopia, which were previously reported from this area, were not found in the present survey. Moreover, recent analysis of the occurrence and synonymy of species of orders Trypanorhyncha and Onchoproteocephalidea revealed that the previous identification of the cestodes in elasmobranchs as Grillotia (Christianella) minuta and Acanthobothrium coronatum, as well as identification of the cestodes in teleosts as Tentacularia sp. larvae, is incorrect due to the absence of their sp","PeriodicalId":18191,"journal":{"name":"Marine Biological Journal","volume":"4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90051714","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fungi of the Black Sea basin: Directions and perspectives of research","authors":"N. Kopytina","doi":"10.21072/mbj.2019.04.4.02","DOIUrl":"https://doi.org/10.21072/mbj.2019.04.4.02","url":null,"abstract":"Totally 71 literature source focused on the study of the Black Sea fungi (micromycetes) for the period from 1867 to 2018 was analyzed. In the 1860s and 1930s Zostera marina sea grass epidemics were recorded caused by fungi-like organisms of the genus Labyrinthula. In the late 19th and early 20th centuries, several cases of seagrass local mycosis were also identified. In the 1960s–2000s invertebrate epizootics caused by fungi were recorded: Hyphochytrium peniliae species parasitized on the Cladocera Penilia avirostris and caused its mass death; fungus Leptolegnia pontica infected eggs of Cirripedia Balanus improvisus and significantly reduced the population fecundity; the invasion of the fungus Ostracoblabe implexa led to the destruction of the Ostrea edulis oyster populations. Currently, single cases of the lesions on the cultivated oyster Crassostrea gigas (its spat is brought from other countries) by O. edulis are noted. Fungi-epibionts were isolated from the shells of C. gigas and Mytilus galloprovincialis. Microsporidia Steinhausia mytilovum was identified in mature oocytes of M. galloprovincialis. On the surface of fish and in their internal organs, filamentous fungi and intracellular parasites (microsporidia) were found. Fungi were revealed on the surface of bottlenose dolphins. The study of pelagial, benthal, cellulose-containing substrates’, foams’, periphyton, micro- and macroalgae, seagrasses mycobiota was carried out. Currently, 435 species of fungi were found in the Black Sea basin. They belong to 212 genera, 84 families, 50 orders, 19 classes, and 3 kingdoms. Totally 372 species were recorded in the marine environment, 196 were found in the freshwaters, and 31 species was recorded in the hypersaline waters. In the water column, 230 species of fungi were identified (in the hydrogen sulfide zone – 21); in the bottom sediments – 202 (in the hydrogen sulfide zone – 31); 70 species were recorded on wood; 30 – in periphyton on glasses and artificial stony supralittoral (berths, traverses); 46 – in marine foam; 50 – on/in molluscs; 18 – on the skin of dolphins; 116 – on macroalgae; 2 – on microalgae; 38 – on seagrasses; 69 – on/in fish; 14 – on/in crustaceans. The number of species found in the coastal waters of different regions is: Georgia – 8; Gelendzhik (Russia) – 56; Crimean Peninsula – 276; the north-western part of the Black Sea – 177; Romania – 112; Bulgaria – 44; Turkey – 9; Danube River – 238; Snake Island – 30. This review reflects individual studies on the fungi ability to utilize cellulose, petroleum and its products, phenol, and sulfur and to cause corrosion of metals. The first results in the study of antimicrobial activity of facultative and obligatory marine fungi of the Black Sea, as well as the ability of fungi to luminescence, are considered. This article lists directions of research in marine mycology that are perspective for the further study.","PeriodicalId":18191,"journal":{"name":"Marine Biological Journal","volume":"20 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73531546","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Findings of spat of bivalve mollusc Crassostrea gigas (Thunberg, 1793) in Donuzlav Lake and Artillery Bay (Crimea, the Black Sea)","authors":"M. Popov, S. V. Schurov","doi":"10.21072/mbj.2019.04.4.10","DOIUrl":"https://doi.org/10.21072/mbj.2019.04.4.10","url":null,"abstract":"The spat of the bivalve mollusc Crassostrea gigas (Thunberg, 1793) was found and photographed on artificial and natural substrates in Donuzlav Lake and Artillery Bay. However, up to this point the planktonic larval stages of C. gigas were not registered in this water areas.","PeriodicalId":18191,"journal":{"name":"Marine Biological Journal","volume":"79 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72439415","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Morphological features of the Black Sea turbot (Scophthalmus maeoticus) during the period of embryonic development","authors":"A. Khanaychenko, V. Giragosov","doi":"10.21072/mbj.2019.04.4.06","DOIUrl":"https://doi.org/10.21072/mbj.2019.04.4.06","url":null,"abstract":"Black Sea turbot (hereinafter BST), Scophthalmus maeoticus (Pallas, 1814), is a valuable fish for commercial fishery and promising object of industrial mariculture. Potential fecundity of BST is very high, 3–13 million eggs; however, survival of its progenies during early development in the sea is unpredictable and low (mortality is up to 90 %). In nature fertilized pelagic BST eggs rise to the sea surface in 2–3 hours; BST develop in upper waters being part of neuston till hatching. BST on its early stages of development could be considered the most vulnerable as the embryo is exposed to diverse adverse effects. The survival and physiological state of the larvae at hatching till exogenous feeding depend on the norm of morphological characteristics of the embryos during their development. Our aim was to study the norm of the changes in BST morphological characteristics during embryogenesis. Morphological analysis of the BST embryogenesis stages from fertilization till hatching on the basis of detailed study of intact embryos (> 2000 eggs) sampled from different experimental batches incubated under experimental conditions is presented. Digital photos and videos of alive eggs were taken with Canon PowerShot A720 using binocular microscope MBS-10 at magnification 8×4 and under light inverted microscope Nikon Eclipse TS100, equipped with analog camera, at magnification ×4, ×10, and ×40. The morphological features of embryogenesis in BST before and after fertilization, cleavage, blastulation, gastrulation, epiboly, and neurulation and until hatching are presented by photos with detailed description of transforming embryological structures. Fertilized pelagic BST eggs covered by transparent shell vary from (1.26 ± 0.14) to (1.31 ± 0.15) mm in diameter, have homogenously distributed yolk and a single round transparent oil drop of 0.20–0.21 mm, positioned at the top of the yolk. Scale of timing of morphological changes is presented in relative time units (as a time interval from fertilization until the emergence of morphological structure in percentage of the total duration of embryogenesis, % RT). Cleavage starts at 2.5 % RT. Cell division desynchronizes between the 6th and 7th cleavage, at 128 blastomeres. Yolk syncytial layer controlling processes of epiboly, cells differentiation, and morphogenesis is formed during the 10th–11th mitotic cycle (12 % RT, about 512–1024 cells). From the germ ring registered at 21 % RT, the embryonic shield develops (at 25 % RT), and organize formation of embryonic axis from 20 to 50 % epiboly (31 % RT). During 70–75 % epiboly (40–45 % RT), the neural keel is formed; notochord and optical primordia become visible; Kupffer’s vesicle emerges at the start of segmentation. Optic cups develop, and more than 20 somites are observed at the end of epiboly (49 % RT). By 60 % RT the Kupffer’s vesicle disappears in tail bud formed; lens placodes are formed in optic cups. Notochord vacuolization, myotomes formation, and tail growth ","PeriodicalId":18191,"journal":{"name":"Marine Biological Journal","volume":"14 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85035519","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"First data on Bivalvulida myxosporeans of Nha Trang Bay mullets (Vietnam)","authors":"V. Yurakhno, Ha Vo Thi","doi":"10.21072/mbj.2019.04.4.07","DOIUrl":"https://doi.org/10.21072/mbj.2019.04.4.07","url":null,"abstract":"Mullets are objects of fishery in Vietnam; some of them are raised in rice paddies. Intensive development of fish mariculture in this country, as well as a large proportion of hydrobionts in the population diet, requires knowledge not only of the species composition of parasites, but also of their life cycles, pathogenicity, medical and epizootiological significance. The fauna of marine myxosporeans in this area has been studied very poorly. Totally 36 species of Myxosporea in freshwater fishes of Vietnam are known and 10 are not identified; 7 species of myxosporeans are found in marine fishes and 9 are not identified. In March – April of 2018 in the Nha Trang Bay (Vietnam, South China Sea, which the Vietnamese call the East Sea) 71 specimens of 7 species of Mugilidae fish were examined for identifying myxosporeans by the method of incomplete parasitological autopsy (4 specimens Chelon planiceps, 25 specimens Valamugil speigleri, 10 specimens V. formosae, 1 specimen Planiliza subviridis, 19 specimens Paramugil parmatus, 9 specimens Mugil cephalus, 3 specimens Moolgarda seheli). All organs were examined under Olympus SZ61 binocular microscope at magnification from ×15 to ×25. Smears from the tissues of various fish organs were examined under Olympus CKX53 microscope with phase contrast at magnification ×400 and under Olympus CX41 microscope with the Olympus SC50 digital camera and phase contrast at magnification ×800. Myxosporeans were fixed in glycerol-gelatin according to the standard technique. Parasite measurements were based on 20 Myxobolus spinacurvatura spores, 25 Sphaerospora dicentrarchi spores, and 10 Henneguya sp. spores. All measurements were carried out by the standard method. To assess the number of parasites, data on prevalence and intensity of invasion were used. The first data on Bivalvulida myxosporeans of Mugilidae fish in Nha Trang Bay were obtained: Myxobolus spinacurvatura was found in the gallbladder and intestine of 78 % Mugil cephalus with the intensity of invasion of unit spores in the gallbladder smear and 5–11 cysts in the intestine; Sphaerospora dicentrarchi was found in the gallbladder of 5 % Paramugil parmatus, 12 % Valamugil speigleri, 20 % V. formosae and 56 % Mugil cephalus with the intensity of invasion of unit spores in the smear; Henneguya sp. was found in the gallbladder of 8 % V. speigleri and 10 % V. formosae with the intensity of invasion of unit, tens of spores in the smear. Description of the revealed species was made. Their distribution in other regions of the World Ocean was considered. S. dicentrarchi turned out to be a new species for the fauna of the East Sea and Vietnam. This species was found not only in Mugil cephalus, the typical host in other regions, but also in new hosts Paramugil parmatus, Valamugil speigleri, and V. formosae. Myxobolus spinacurvatura was first found in the Nha Trang Bay. Since Myxobolus spinacurvatura and Sphaerospora dicentrarchi are known in Mugil cephalus not only in the ","PeriodicalId":18191,"journal":{"name":"Marine Biological Journal","volume":"34 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76907607","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modern state of the reproductive potential of Black Sea sprat Sprattus sprattus phalericus (Risso, 1826) (Pisces: Clupeidae) in Crimean region and conditions for its formation","authors":"G. Zuyev","doi":"10.21072/mbj.2019.04.4.01","DOIUrl":"https://doi.org/10.21072/mbj.2019.04.4.01","url":null,"abstract":"Black Sea sprat Sprattus sprattus phalericus (Risso, 1826) is one of the abundant species of fish in the Sea of Azov – Black Sea basin. Due to its large number sprat plays an extremely important role in the ecosystem of the sea, being an intermediate link between zooplankton and representatives of the highest trophic level – large predatory fish, dolphins, and birds. At the same time sprat is one of the important commercial fish in all the Black Sea countries, steadily being on the second place of catch volume in recent decades (after anchovy). The total catch reaches 100 thousand tons. Turkey and Ukraine are the main producing countries. Monitoring and forecast of biological state of sprat population with rising fishing intensity and climate changes are urgent tasks. The research subject of this article is the long-term (2000–2016) dynamics of biological (qualitative) parameters determining the population fecundity of Black Sea sprat in Crimean region, the current state of reproductive potential, and the conditions for its formation. The article is based on the results of own research. Parameters determining the population fecundity – the length-age structure of the spawning part population, the absolute individual fecundity, and the sex structure population (ratio between females and males) – were studied. In the long-term plan (in 2011–2016 compared with 2000–2004) the average length of spawning females decreased by 1.22 times (from 7.36 to 6.03 cm). It was accompanied by a decrease in the absolute individual fecundity by 2.39 times (from 13 625 to 5690 eggs). The numerical ratio between females and males decreased by 1.23 times (from 1.95 to 1.59). Simultaneously the sprat stock in the northern part of the Black Sea was reduced by more than 2.5 times (from > 500 thousand tons to < 200 thousand tons). As a result, the population fecundity of sprat in Crimean region decreased by more than 7 times (2.39 × 1.23 × 2.5). The conditions of sprat fishing in the northern part of the Black Sea (from the mouth of the Danube River to the Kerch Strait) were studied. They showed 2-fold decrease (from 251.9 thousand tons in 2000–2004 to 129.1 thousand tons in 2011–2016) in the total catch and more than 2.3-fold decrease (from 50.4 to 21.4 thousand tons) in average annual catch in this region. On the contrary, in the Crimean shelf the total catch at that time increased by 1.2 times (from 76.9 to 92.2 thousand tons), and its average annual value remained constant (15.4 thousand tons). While reducing the stock by 2.5 times, this means that the fishing pressure on the Crimean population increased 2.5 times. This fact suggests considering the factor of fishing as the main cause of its degradation. Validity of this version is confirmed by the fact of conjugacy (inverse connection) of interannual fluctuations between the catch and the length-age parameters of sprat in Crimean region in 2003–2013 previously found: catches over 15–16 thousand tons were accompanied b","PeriodicalId":18191,"journal":{"name":"Marine Biological Journal","volume":"14 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84581274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Chlorophyll concentration in marine microalgae biomass under the condition of light limitation (model)","authors":"R. P. Trenkenshu, T. Novikova","doi":"10.21072/mbj.2019.04.4.11","DOIUrl":"https://doi.org/10.21072/mbj.2019.04.4.11","url":null,"abstract":"The paper presents a mathematical model of light-dependent chlorophyll concentration in the marine microalgae biomass. The model is based on the concept of biomass as the sum of reserve and structural macromolecular forms of organic cell matter. At the same time, chlorophyll refers to structural forms of biomass. Using such concepts, it is possible to apply known equations for light-dependent content of structural forms in biomass. The proposed equation describes well the experimental results obtained in a number of experiments with the chlorophyllostate culture Tetraselmis viridis.","PeriodicalId":18191,"journal":{"name":"Marine Biological Journal","volume":"12 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83062420","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}