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The work examines the manifestation of quasi-permanent sources of oil slick structures in the Sea of Marmara based on analysis of Sentinel-1 C-SAR radar and Sentinel-2 MSI and Landsat-8, -9 OLI optical satellite data. An area of regular occurrence of these sources in the northwestern part of the water area was identified, and the slick structures associated with them were mapped using radar images. A comparison of the discovered slicks with the topography of the seabed of the study area was carried out and it was noted that their most frequent manifestation is observed in the zone of the depth slope and above the plateau between deep-sea basins, which corresponds to the data of acoustic sounding of gas intrusions. Typical forms of manifestation are considered, and estimates of spatial characteristics of slick structures and their maximum lifetime are made. Based on the results of the analysis of optical satellite images, examples are given with changes in the reflectance of the water–film system. For a case with optically "thick" film, a method for estimating the volume of contamination is proposed. [ABSTRACT FROM AUTHOR]

The North Anatolian Fault (NAF) extends for over 1,000 km across Türkiye and poses significant seismic hazard in the region. The Main Marmara Fault (MMF) segment of the NAF in the Sea of Marmara (NW Türkiye), exhibits along‐strike segmentation in its interseismic strain accumulation. Constraining the lithospheric configuration below the MMF is critical to understand its segmentation and assessing seismic hazard in the area. We present a new 3D lithospheric‐scale density of the Sea of Marmara, that combines gravity modeling and seismic tomography analysis. Using forward and inverse gravity modeling with free‐air gravity data and available constraints of geological units we derived the intra‐crustal density structure. Shear‐wave velocity tomography models provided insights into the temperature and density configuration of the uppermost mantle, and the geometry of the 1330°C isotherm. Our results highlight significant crustal density variations: lower‐density crust in the Sakarya Zone and Strandja Massif, and denser crust below the Istanbul Zone, which overlies a relatively hotter lithospheric mantle. This lithospheric configuration reflects both ongoing tectonic processes and inheritance from past geological events, including the drifting of the Istanbul Zone crustal block and the signature of past subduction events. The extent of the Istanbul Zone denser crust spatially correlates with the locked segment of the MMF. The bimaterial nature of the fault segment likely influences its interseismic and coseismic behavior. The denser, stiffer Istanbul Zone crust would promote interseismically locked conditions in contrast to the adjacent, more compliant crustal block and could result in asymmetric rupture with a preferred directivity. Plain Language Summary: The North Anatolian Fault (NAF) is a major fault that runs for more than 1,000 km across Türkiye and which poses important seismic hazard in the region. A segment of this fault, named the Main Marmara Fault, runs under the Sea of Marmara in NW Türkiye, and displays different seismic behaviors along its length. To understand better the fault's behavior, we have investigated the geometry and physical properties (density and temperature) of the rock layers beneath the Sea of Marmara, for up to several tens of kilometers depth. We found that the crust is thicker and denser in some places of the study area and thinner and less dense in others places, with main changes occurring across the MMF. We also found that the mantle (the layer under the crust) has different temperatures across the study area, with some places being hotter than others. This configuration of the rock layers below the Sea of Marmara, with varying densities and temperatures, can potentially explain why part of the MMF fault is locked, and it also has important implications for the seismic hazards in the area. Key Points: Sea of Marmara lithosphere is variable, with the denser and thicker Istanbul Zone crust underlain by relatively shallower 1330°C isothermLithospheric configuration correlates with MMF fault segmentation: denser Istanbul Zone crust coincides with the locked fault segmentOur findings have implications for seismic hazards, suggesting potentially higher risk in Istanbul Zone due to rupture directivity [ABSTRACT FROM AUTHOR]

Beachrock formations represent a powerful paleo-environmental proxy in tectonically active coasts because they are ideal marker horizons for reconstructing past sea-level positions and revealing vertical uplift rates. In this study, beachrocks from the Tekirdağ-Altınova coastal area were used to model the evolution of the late Holocene coastline in the northern Sea of Marmara. As the Tekirdağ-Altınova coastal area is located in the tectonically active western Marmara region, this study aimed to investigate the role of tectonic processes in the late Holocene evolution of the coastal landscape in the study area by assessing long-term vertical deformation rates. To document and estimate coastal uplift, lesser known submerged beachrocks within the nearshore coastal area of the northern Sea of Marmara were analyzed with novel laser ablation (LA)–accelerator mass spectrometry (AMS) and standard 14C-AMS techniques and correlated with late Holocene sea level variations. The preservation state of these beachrocks allowed for their identification and mapping through the use of an unmanned aerial vehicle (UAV) equipped with a high-resolution (5 cm) camera, followed by sampling via the coring method. The determined ages of marine shells and calcite cements from selected samples of submerged beachrock span between 2.6 and 13.6 ky BP. These ages could be correlated with the late Holocene sea-level highstand and were used to estimate the long-term uplift rate. Based on these findings, an uplift rate of approximately 0.56–0.79 mm/yr over the last 6500 years has been suggested for the area studied. [ABSTRACT FROM AUTHOR]

Copyright of Ege Journal of Fisheries & Aquatic Sciences (EgeJFAS) / Su Ürünleri Dergisi is the property of Ege Journal of Fisheries & Aquatic Sciences (EgeJFAS) / Su Urunleri Dergisi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Globally, all marine ecosystems are under pressure by anthropogenic stressors. However, semi-enclosed seas are at a greater risk of degradation due to their limited connectivity to open seas. This leads to a greater accumulation of pollutants and abrupt regime shifts triggered by unsustainable exploitation of living resources, as ecosystems exhibit low degrees of redundancy and more frequent large-scale episodic events such as harmful algal blooms. The Sea of Marmara is a semi-enclosed marine region that has been subjected to various anthropogenic stressors since the 1990s. Recently, local and governmental authorities have employed basin-wide ecosystem management plans to control and manage point and nonpoint (diffuse) sources of pollutants. However, the management of fisheries in relation to the dynamics of the Sea of Marmara food web has attracted less attention from policymakers, even though fisheries exploitation is one of the most significant anthropogenic pressures. In this study, we capitalized on a previous static ecosystem model of the Sea of Marmara by revising and extending it to simulate the changes between 1990 and 2020. We delineated the temporal dynamics and regime shifts in the food web in terms of ecosystem structure and function by using ecological indicators and developed quantitative management advice for its fisheries. The results showed that the ecosystem has experienced three regimes since 1990, with regime shifts occurring with the onset of the 2000s and the mid 2010s. The first regime exhibited high diversity and material cycling, the second regime was characterized by low diversity and increased impact of fisheries, and the third regime culminated in a fished-down food web state. The analysis of fishery dynamics showed that the majority of harvested species were overexploited. We suggest that the implementation of quotas for exploited species should be considered an immediate solution to the unsustainable exploitation of fish stocks and can help restore ecosystem conditions. [ABSTRACT FROM AUTHOR]

This is an updated compilation of marine arthropod species reported from the coasts of Türkiye. As of the first half of 2024, 1886 arthropod species have been reported in the marine and brackish water environments of Türkiye. The class Malacostraca, having the highest number of species, is followed by Copepoda, Ostracoda, Arachnida, Pycnogonida, Thecostraca, Branchiopoda, and Insecta in terms of species diversity. Additionally, 83 alien species have been identified. [ABSTRACT FROM AUTHOR]

Seasonal changes in the composition and abundance of zooplankton and their responses to environmental changes were investigated at 30 stations in the upper layer and 13 stations in the lower layer (in February, May, July, and December) of the Eastern Marmara Sea in 2016. A total of 44 species/groups (including jellyfish species) were documented in the study area, with 39 identified in the upper layer water and 31 in the lower layer water. The abundances of zooplankton ranged from 29 to 2822 ind.m-3 in the upper layer and from 6 to 2283 ind.m-3 in the lower layer. Acartia clausi, Paracalanus parvus, Penilia avirostris, and Oithona similis were the dominant species in summer and autumn, whereas Calanus euxinus, Pseudocalanus elongates, Oithona nana, Oithona davisae and Pleopis polyphemoides were the dominant species in winter and spring. Aetideus spp., Clausocalanus spp., Ctenocalanus vanus, Oncaea minuta, Isopoda, and Siphonophora were observed only in bottom-layer waters. M. lucens and O. davisae were recorded only in the upper layer in December. In conclusion, our results suggest that zooplankton communities and some species are favorable indicators of the marine environment of the Sea of Marmara. [ABSTRACT FROM AUTHOR]

Copyright of Ege Journal of Fisheries & Aquatic Sciences (EgeJFAS) / Su Ürünleri Dergisi is the property of Ege Journal of Fisheries & Aquatic Sciences (EgeJFAS) / Su Urunleri Dergisi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A total of thirty-one adult individuals and four embryos of Torpedo marmorata Risso, 1810 were caught as bycatch with trammel nets by commercial fishermen in the southwestern Sea of Marmara, Türkiye. The length-weight relationships (LWRs), lengthlength relationships and some biological properties of the individuals were investigated. The LWRs for males, females, and all sexes were estimated as TW=0.0152TL3.0437, TW=0.0129TL3.1029 and TW=0.0124TL3.1122 (TW: Total weight, TL: Total length), respectively. The growth type was identified as isometric for males, females, and all sexes. According to morphometric measurements, only difference was between total length and disc length ratios of female and male individuals. The minimum, maximum and mean condition factors were estimated for adults as 1.493, 2.179 and 1.801±0.03, respectively. These results increase the knowledge on T. marmorata stocks distributed in the Sea of Marmara and expected to contribute for future studies on the species. [ABSTRACT FROM AUTHOR]

Globally, all marine ecosystems are under pressure by anthropogenic stressors. However, semi-enclosed seas are at a greater risk of degradation due to their limited connectivity to open seas. This leads to a greater accumulation of pollutants and abrupt regime shifts triggered by unsustainable exploitation of living resources, as ecosystems exhibit low degrees of redundancy and more frequent large-scale episodic events such as harmful algal blooms. The Sea of Marmara is a semi-enclosed marine region that has been subjected to various anthropogenic stressors since the 1990s. Recently, local and governmental authorities have employed basin-wide ecosystem management plans to control and manage point and nonpoint (diffuse) sources of pollutants. However, the management of fisheries in relation to the dynamics of the Sea of Marmara food web has attracted less attention from policymakers, even though fisheries exploitation is one of the most significant anthropogenic pressures. In this study, we capitalized on a previous static ecosystem model of the Sea of Marmara by revising and extending it to simulate the changes between 1990 and 2020. We delineated the temporal dynamics and regime shifts in the food web in terms of ecosystem structure and function by using ecological indicators and developed quantitative management advice for its fisheries. The results showed that the ecosystem has experienced three regimes since 1990, with regime shifts occurring with the onset of the 2000s and the mid 2010s. The first regime exhibited high diversity and material cycling, the second regime was characterized by low diversity and increased impact of fisheries, and the third regime culminated in a fished-down food web state. The analysis of fishery dynamics showed that the majority of harvested species were overexploited. We suggest that the implementation of quotas for exploited species should be considered an immediate solution to the unsustainable exploitation of fish stocks and can help restore ecosystem conditions.

Fan mussel (Pinna nobilis) is one of the largest bivalve species in the Mediterranean Sea. The situation of the species is critical as it faces widespread mass mortality attributed to pathogens in various parts of the Mediterranean Sea. The Sea of Marmara (SoM) offers a unique environment for fan mussel populations, with some areas hosting alive populations. This study aims to explore and describe new P. nobilis populations in the SoM that are known to be not affected by mortality. An area of 28,200 m2 at 47 stations along the 105 km coastline in the southern part of the SoM was explored using underwater visual transects. A total of 544 alive fan mussels were recorded during the underwater surveys, ranging in total shell height from 11.8 to 31.4 cm. The mean density was estimated as 5.3 ind 100 m−2 although maxima of 18.8 ind 100 m−2 were recorded in some stations. These density hotspots were distributed from the shoreline to a 10 m depth range and 100 m distance from the shoreline in sandy and seagrass meadow habitats. The presence of juveniles provided evidence of successful recruitment. The distribution pattern and recorded mortalities were attributed to hydrodynamic factors and intense human activities. Potential environmental factors (low salinity and temperature) in the SoM may control or delay the possible spread of the lethal pathogens. Favorable conditions result in mussels’ resilience and survival mechanisms. The SoM offer a promising larval reservoir for the recolonization of affected areas, such as those found in the Aegean Sea, through larval exportation. [ABSTRACT FROM AUTHOR]

This study reports our observation of the large sea slug Tethys fimbria Linnaeus, 1767 in the northern-eastern Sea of Marmara (the Princes’ Islands). We observed T. fimbria on the detrital bottom of the sea at a depth of 35 m in June 2022. This species had previously been reported during spawning in a recent study conducted in the southern part of the Çanakkale Strait (the Dardanelles Strait that connects the Marmara Sea with the Aegean Sea). Prior to 2022 there had been no reports of this conspicuous species from the Marmara Sea in the scientific literature or in photo-records among divers. Following our observation of the species in the sea around the Princes’ Islands, underwater photographers reported pictures of T. fimbria from different locations in the Marmara Sea on social media platforms. The sea slug seems to extend its distribution northwards. The potentially new arrival of the large sea slug in the Sea of Marmara, rather than a distribution shift from deoxygenated deep Marmara basins or a climate-related northwards expansion, is discussed.

The natural distribution of the Japanese sea cucumber (Apostichopus japonicus Selenka, 1867), a sea cucumber species, is characterized by the Northwest Pacific. Long-term monitoring studies from 2020 to 2024 document a significant deviation from the known natural distribution of A. japonicus and its ability to extensively colonize the Gulf of Izmit, the easternmost part of the Sea of Marmara. This record is also the first documentation of the species from the Mediterranean Sea. Population data extracted from 67 samples allowed the determination of size and weight distribution, length-weight relationship, and condition factor. The study delves into the implications for fisheries management by evaluating the species' dispersion beyond its natural range and its adaptation, shedding light on potential threats from illegal hookah diving fisheries. While its presence offers potential economic benefits through fishing income, its emergence as an invasive species can pose critical ecological risks to the receiving ecosystem. [ABSTRACT FROM AUTHOR]

A new species of the monotypic genus Troglophonte Huys & Lee, 2000 (Harpacticoida, Laophontidae) was discovered among the interstitial samples collected from the Kumada Coast in the Sea of Marmara. The new species can be distinguished from the type species T. spelaea (Chappuis, 1938) by the following characters: (i) female 6-segmented antennule, (ii) P3 exp terminal segment with 7 setae, (iii) female P5 exopodal lobe with 5 setae, (iv) female P5 baseoendopod with 3 setae on endopodal lobe, (v) surface ornamentation of swimming legs, (vi) male P5 baseoendopod distal seta ornamentation, and (vii) male P5 exopod setal ornamentation. The type material of T. spelaea does no longer exist and its diagnosis is concise. Therefore, the generic diagnosis has been updated to include the characters displayed by the new species. Additionally, a phylogenetic analysis including other genera related to the Troglophonte was conducted using parsimony. The results obtained from the phylogenetic analysis were generally consistent with the previous studies. [ABSTRACT FROM AUTHOR]

Understanding the dynamics of pelagic fish fluctuations is crucial to ecosystem well-being and sustainable fishery. Here, inter- and intra-annual landing dynamics of small and medium pelagic fish were delineated between 2000 and 2022 in the landlocked Sea of Marmara. Time series of environmental variables and fisheries landings were analyzed for their trends and inter-correlations. Results showed that variations in the landings of small and medium pelagic fish in the Sea of Marmara had strong seasonality and were very likely affected by fishing effort, and sea surface temperature regimes. During the study period, landings of anchovy, bonito and bluefish, and net primary production showed no significant trends. On the other hand, Mediterranean horse mackerel had a significant decreasing trend, while sardine landings and the sea surface temperature (0.05 ± 0.01 °C/y−1) had a significant increasing trend. Analysis of the duration of the fishing period in a given fishing season showed that reaching 90% of the landings (L90) for anchovy, sardine, and Mediterranean horse mackerel shifted almost one month earlier, and for bonito, L90 showed no change for larger ones, but extended almost one month for small individuals. The multiple linear regression models indicated that the landing dynamics of small and medium pelagic fish were also influenced by the prey-predator relations in the food web. Exploiting anchovy stocks would likely have consequences on the dynamics of bonito and bluefish stocks, and exploiting bonito and bluefish stocks would have a cascading trophic impact on small pelagic fish catches. This study highlights the necessity of adaptive management measures for fisheries under regional sea warming conditions, and a one-and-a-half-month delay in the opening time of the fishing season, thus shortening its duration is strictly recommended. [ABSTRACT FROM AUTHOR]

The Sea of Marmara, located in Northwestern Türkiye, is under multiple stressors, including climate change and industrial, agricultural, and domestic pollution, that cause deoxygenation in coastal waters, with multiregional consequences affecting the surface and deep-water masses transported to the Mediterranean and Black Seas, respectively, via its straits. With climate-change driven changes in the intensity of extreme precipitation events, the marine environment becomes more vulnerable to increasing terrestrial pollutants. Evaluating the spatial and temporal variation of river runoff is crucial to understanding the interaction between the geophysical and hydrogeochemical processes that affects the nutrient balance of the sea. This study aims to (i) explore the historical (for the period 1960-2021) and spatial changes of monthly-averaged coastal discharges along the coastline of the Sea of Marmara for the first time, based on observations from the national hydrological service; (ii) analyze the change in long-term and seasonal trends of runoff and net-precipitation rate and derive a regional relation between the two parameters. Single Spectrum Analysis (SSA) is used to obtain the trends. Gaps in the time series are filled in using a non-parametric spectral estimation method. Discharges from the northern, eastern, and southern basins are, respectively, 3%, 17%, and 80% of the total discharge, which has varied between 1.5 and 15 km3 per year in the last decade, with short-lived extremes occurring in early spring. Total runoff rate shows a declining long-term trend that is accelerating with increasing evaporation. The intensity of the terrestrial precipitation extremes shows a temporal increase; there is a quadratic relation between the long-term trends of net precipitation and total runoff. Quantification of nutrient load distribution along the coastline associated with the spatial-temporal changes in coastal fluxes is urgent because the cumulative stressors (warming, nutrient overenrichment, pollutants) pose a threat of triggering extreme events and eutrophication in the Sea of Marmara with multiregional impact.

The cellular carbon content based on the cell biovolume of a total of 61 microalgal species determined in a eutrophic estuary (Golden Horn, Sea of Marmara) was estimated in seawater samples taken during two different sampling periods. Cell biovolume according to geometric dimensions of the cells was then converted to phytoplankton carbon using an appropriate conversion factor. The range of diatom biovolume, in which the majority had small cell sizes (<50 μm), was much wider than that of dinoflagellate biovolume, in which the majority had large cell sizes (>50 μm). The cell biovolume and carbon content ranged from 35 to 4.88 × 105 μm3 and 5 to 1.18 × 104 pgC cell−1 for diatoms and from 3.66 × 102 to 8.68 × 105 μm3 and 55 to 8.14 × 104 pgC cell−1 for dinoflagellates, respectively. The mean carbon density for diatoms and dinoflagellates (excl. Noctiluca scintillans) varied between 0.027 and 0.099 pgC μm−3 0.096 and 0.136 pgC μm−3, respectively. The mean cell carbon content and carbon density of dinoflagellates (6.73 × 103 pgC cell−1 and 0.115 pgC μm−3) were approximately 10 and 2 times greater than those of diatoms, respectively. The carbon content of the other phytoflagellates was lower, whereas their carbon density was higher. As a result, the findings from this study will provide a significant contribution to the assessment and estimation of carbon biomass during algal blooms in this study area. [ABSTRACT FROM AUTHOR]

This study reports our observation of the large sea slug Tethys fimbria Linnaeus, 1767 in the northern-eastern Sea of Marmara (the Princes' Islands). We observed T. fimbria on the detrital bottom of the sea at a depth of 35 m in June 2022. This species had previously been reported during spawning in a recent study conducted in the southern part of the Çanakkale Strait (the Dardanelles Strait that connects the Marmara Sea with the Aegean Sea). Prior to 2022 there had been no reports of this conspicuous species from the Marmara Sea in the scientific literature or in photo-records among divers. Following our observation of the species in the sea around the Princes' Islands, underwater photographers reported pictures of T. fimbria from different locations in the Marmara Sea on social media platforms. The sea slug seems to extend its distribution northwards. The potentially new arrival of the large sea slug in the Sea of Marmara, rather than a distribution shift from deoxygenated deep Marmara basins or a climate-related northwards expansion, is discussed. [ABSTRACT FROM AUTHOR]

A giant piston core MRS-CS27 sedimentary sequence in the Sea of Marmara (SoM) was investigated by palynological analysis to evaluate the paleoenvironmental and climate changes, corresponding to the Marine Isotope Stages MIS-5 (c-a), MIS-4, MIS-3, and the earliest part of the MIS-2. During MIS-5c, the palynological analysis indicates a warm and humid climate in the SoM. The pollen assemblage is characterized by the presence of broad-leaved deciduous woody taxa, with a predominance of deciduous Quercus. Following MIS-5c, a relatively colder and drier climate is inferred during MIS-5b, as indicated by the herbaceous assemblages found in the sedimentary sequence. The presence of herbaceous plants in the pollen record suggests less favorable conditions for woody vegetation and a shift towards a cooler and drier climate compared to the previous phase. Within the MIS-5a interval, the palynological analysis reveals the presence of abundant mesophyllous woody taxa. This indicates a return to a warm and humid climate during this period, supporting the growth of diverse forest vegetation. Distinct changes in vegetation are observed during MIS-4, with the presence of abundant Cedrus pollen. This suggests the survival of montane trees in the region under a cooler climate compared to the previous stages. Relict plants such as Cathaya , Tsuga , and Carya are identified during MIS-3 and MIS-4. Their presence can be attributed to the reworking of older sediments during these periods, indicating that these plants were not contemporary with the sediment but were preserved from earlier time periods. [ABSTRACT FROM AUTHOR]

The North Anatolian Fault Zone (NAFZ) is the most prominent active fault system in Northwestern Turkey. It is a major fracture that traverses the Northern part of Asia Minor and marks the boundary between the Anatolian tectonic plate and the larger Eurasian continental block, and has been the source of numerous large earthquakes throughout history. The NAFZ splits into three strands at the eastern part of the Marmara Sea. The northern strand passes through Izmit Bay, traverses the Marmara Sea and reaches to the Saros Gulf. The central fault zone passes through Izmit Bay, traverses the Sea of Marmara and reaches the Saros Gulf to the southeast. Earthquakes on this zone involve primarily horizontal ground motions (strike-slip type of faulting). Because of this unstable tectonic system, the area is considered to be as one of the most seismically active zones of the world. In the last hundred years, numerous large earthquakes have also occurred along the NAFZ, in the western part of Turkey. Beginning with an earthquake in 1939, several more quakes - with Richter magnitudes greater than 6.7 - struck in progression along adjacent segments of the great fault. The August 17, 1999 Izmit earthquake was the eleventh of such a series that have broken segments of the NAFZ, in both eastward and westward direction. The epicenter of the 1999 earthquake was near Izmit, as well as the location of previous events. The sequence of historic events indicates that the next destructive tsunamigenic earthquake could occur west of the 1999 event in the Sea of Marmara. The present study incorporates the results of a subsequent 2001 study which uses standardized remote sensing techniques and GIS-methods – based on Digital Elevation Model (DEM) data, and on geo- morph metric parameters that influenced local site conditions in the Sea of Marmara, as determined with Digital elevation data of the Shuttle Radar Topography Mission (SRTM), and with high resolution ASTER-data. With such remote sensing methods, areas that are potentially vulnerable areas in the Sea of Marmara were detected, so that disaster mitigation strategies can be implemented more effectively in the future. Based on such technology, local site conditions, which exacerbated earthquake intensities and collateral disaster destruction in the Marmara Sea region, were identified. Also reviewed by the present study are the similarities of NAFZ with the San Andreas fault in California in the USA, for the formation of an active transform boundary of the strike-slip type, with the two sides moving horizontally and continuously past each other. Finally examined is the tectonic and continuing geodynamic evolution and collision between the Arabian Plate and Eurasia, which places in danger many cities in southeastern Turkey and NorthWest Syria - which is are located on the boundary with the Arabian tectonic plate, as evidenced by the recent disastrous earthquake of 8 February 2023 along the Eastern Anatolian Fault Zone (EAFZ).

The mucilage outbreak in the Sea of Marmara in the spring of 2021 has once again emphasized the importance of addressing climate and pollution associated hazards. Although multispectral images have traditionally been used for such purposes, an analysis of marine mucilage, with its spectral similarity to marine debris, and its spectral variations due to composition and/or sediment or bacterial aggregation, is a prime candidate to benefit from the advantages of hyperspectral data. The recently launched PRISMA mission provides an important opportunity to this end. This work proposes the use of unmixing on PRISMA datasets in order to analyze the spectral characteristics, the variation due to aggregation, and the spatial distribution, of marine mucilage. The proposed approach provides consistent and relevant information on two different datasets, with the potential to benefit cleaning and understanding efforts for marine mucilage. In addition, unlike the previous studies with supervised classification, the proposed approach does not require a training step, and the abundance fraction maps obtained using unmixing are easy to interpret and analyze for mucilage aggregation. [ABSTRACT FROM AUTHOR]

There are two species of garfish belonging to the genus Belone (garfish B. belone and short-beaked garfish B. svetovidovi) in the coastal regions of Türkiye. It is known that Belone belone is distributed all around the Turkish coasts, and Belone svetovidovi is distributed only in the Mediterranean and Aegean coasts of Türkiye. These species' morphological similarities and mainly overlapped morphological characters led to confusions for years. The present study represents the first detailed morphological and molecular analysis including twenty-two body portions and DNA barcode analysis of B. svetovidovi and reports the newly established populations in the Sea of Marmara with molecular and morphological evidences. [ABSTRACT FROM AUTHOR]

The North Anatolian Fault Zone (NAFZ) is the most prominent active fault system in Northwestern Turkey. It is a major fracture that traverses the Northern part of Asia Minor and marks the boundary between the Anatolian tectonic plate and the larger Eurasian continental block, and has been the source of numerous large earthquakes throughout history. The NAFZ splits into three strands at the eastern part of the Marmara Sea. The northern strand passes through Izmit Bay, traverses the Marmara Sea and reaches to the Saros Gulf. The central fault zone passes through Izmit Bay, traverses the Sea of Marmara and reaches the Saros Gulf to the southeast. Earthquakes on this zone involve primarily horizontal ground motions (strike-slip type of faulting). Because of this unstable tectonic system, the area is considered to be as one of the most seismically active zones of the world. In the last hundred years, numerous large earthquakes have also occurred along the NAFZ, in the western part of Turkey. Beginning with an earthquake in 1939, several more quakes - with Richter magnitudes greater than 6.7 - struck in progression along adjacent segments of the great fault. The August 17, 1999 Izmit earthquake was the eleventh of such a series that have broken segments of the NAFZ, in both eastward and westward direction. The epicenter of the 1999 earthquake was near Izmit, as well as the location of previous events. The sequence of historic events indicates that the next destructive tsunamigenic earthquake could occur west of the 1999 event in the Sea of Marmara. The present study incorporates the results of a subsequent 2001 study which uses standardized remote sensing techniques and GIS-methods - based on Digital Elevation Model (DEM) data, and on geomorph metric parameters that influenced local site conditions in the Sea of Marmara, as determined with Digital elevation data of the Shuttle Radar Topography Mission (SRTM), and with high resolution ASTER-data. With such remote sensing methods, areas that are potentially vulnerable areas in the Sea of Marmara were detected, so that disaster mitigation strategies can be implemented more effectively in the future. Based on such technology, local site conditions, which exacerbated earthquake intensities and collateral disaster destruction in the Marmara Sea region, were identified. Also reviewed by the present study are the similarities of NAFZ with the San Andreas fault in California in the USA, for the formation of an active transform boundary of the strike-slip type, with the two sides moving horizontally and continuously past each other. Finally examined is the tectonic and continuing geodynamic evolution and collision between the Arabian Plate and Eurasia, which places in danger many cities in southeastern Turkey and NorthWest Syria - which is are located on the boundary with the Arabian tectonic plate, as evidenced by the recent disastrous earthquake of 8 February 2023 along the Eastern Anatolian Fault Zone (EAFZ). [ABSTRACT FROM AUTHOR]

Diet studies are critical for ecosystem-level understanding of fish populations and a move toward ecosystem-based management of marine resources. European hake, Merluccius merluccius, a demersal mesopredator species, is one of the most important commercial fish in the Mediterranean, and as a predatory species it controls the food web. Here, we characterize the diet of M. merluccius with two different analytical methods, visual assessment of stomach contents and DNA metabarcoding. Seasonal and size-based differences in fish prey composition were investigated. Both methods produced complementary results with regard to fish prey contribution of European hake diet. The visual assessment approach showed significant differences between adult and juvenile hakes, while the metabarcoding approach indicated high seasonality in fish prey contribution and richness in its diet. An increase in fish prey diversity was found for both adult and juvenile hakes during the summer. Trachurus sp. was detected as the dominant fish prey in both methods. A broader range of fish prey species was detected by metabarcoding due to its ability to identify highly digested items from the stomach. Combining visual assessment with a novel metabarcoding approach has the potential to improve our understanding of trophic ecology, which can be useful for ecosystem-based management. [ABSTRACT FROM AUTHOR]

Facing and experiencing the recent mucilage event in the Sea of Marmara-Türkiye in 2021 urged the local and state officers together with the related authorities to strengthen and improve the existing environmental auditing system. It is well-known that high pollution loads discharged to the receiving sea environment through land-based sources of point and diffuse loads accelerated the formation of mucilage in line with the warming of the sea surface as a consequence of climate change. In this regard changes, revisions, and particularly sector-specific activities were funded through a project established by the Ministry of Environment, Urbanization, and Climate Change (MoEU) and carried out by a group of academics and MoEU technical specialists. As such, the auding system has been thoroughly improved to prevent further deterioration of the Sea of Marmara surrounded by 7 metropolitan provinces of the country. This study is on the lessons-learnt during the renewal attempts of the auditing system with the aim of benefiting from the recent applications of the other developing and/or regional countries suffering from coastal pollution. [ABSTRACT FROM AUTHOR]

To understand if the formation of mucilage in the Sea of Marmara in 2021 affects the attenuation of light in the water column, data from two different periods were compared. Six stations covering the wide area of the Sea of Marmara and representing regions with different characteristics were selected. The CTD (conductivity, temperature, depth) and PAR (photosynthetically active radiation) values were examined and Kd (attenuation coefficient) was calculated. In order to understand the effect of different typologies of mucilage aggregates on light attenuation, the light data of August 2021 was compare with the light data of January 2021, when these typologies did not occur. As a result of the study, the euphotic zone depth (ZEU) in the Sea of Marmara for the period of August 2021 was limited to the range of 14-23 m. The average attenuation coefficient was 0.242±0.04 m-1. As expected in January, the attenuation coefficient generally decreased with increasing depth, while in August this situation was almost reversed. The evaluation of PAR and Kd data showed that the mucilage aggregates, which become denser and larger with depth, caused serious shading in the water column. [ABSTRACT FROM AUTHOR]

Copyright of Revista de Biologia Marina y Oceanografía (RBMO) is the property of Universidad de Valparaiso, Facultad de Ciencias del Mar and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Peculiarities and negative consequences of an anomalous algal bloom that occurred in the Sea of Marmara in the spring–summer period of 2021 were estimated based on a long time series of satellite data. It was found that the area of extensive accumulations of jelly-like aggregates of organic substances (sea slime) was 973 km2. The most intense biogenic pollutions were found in the coastal waters off the provinces of Çanakkale, Bursa, and Yalova/Kocaeli (Turkey). The set of factors that could contribute to the formation of conditions for such an anomalously intense biogenic pollution has been analyzed. It was shown that the most likely causes of its development are the increase in the temperature of the marine environment (monthly averages were 17% higher than the climatic norm) and the level of photosynthetically active radiation (the excess of the climatic norm by 27%) accompanied by atypical variability of surface wind fields in the region. [ABSTRACT FROM AUTHOR]

Abnormalities of shape, color or body deformities such as lack of swim bladders or any parts of the body are an unexplained issue for many fish species. There is a gap of knowledge regarding their causes. Generally, it is an important problem in the rearing technique in aquaculture management due to the high economic consequences. The morphological abnormalities occur in marine fishes as well. Missing dorsal spines or rays, scale disorientation, jaw deformities, eye deformations and the lack of some parts of the body are within the context of abnormality. In the present study, the bodyabnormalityobservedinaspecimenofEuropeanhake(MerlucciusmerlucciusLinnaeus,1758)missingitsrighteyewhichwascaughtbyafishermanintheMarmaraSeaon13October2020, and its causes are reported and discussed. Further studies are needed to correlate the wild fish anomalies caused by pollution.

Based on morphobathymetric and seismic reflection data, we studied a large landslide body from the eastern Sea of Marmara (NW Turkey), along the main strand of the North Anatolian Fault, one of the most seismically active geological structures on Earth. Due to its location and dimensions, the sliding body may cause tsunamis in case of failure possibly induced by an earthquake. This could affect heavily the coasts of the Sea of Marmara and the densely populated Istanbul Metropolitan area, with its exposed cultural heritage assets. After a geological and geometrical description of the landslide, thanks to high-resolution marine geophysical data, we simulated numerically possible effects of its massive mobilization along a basal displacement surface. Results, within significant uncertainties linked to dimensions and kinematics of the sliding mass, suggest generation of tsunamis exceeding 15–20 m along a broad coastal sector of the eastern Sea of Marmara. Although creeping processes or partial collapse of the landslide body could lower the associated tsunami risk, its detection stresses the need for collecting more marine geological/geophysical data in the region to better constrain hazards and feasibility of specific emergency plans. [ABSTRACT FROM AUTHOR]

Twelve trace elements were studied in four economically important bivalve molluscs (Mediterranean mussel, manila clam, striped venus clam, and truncated wedge clam) from the southern Marmara Sea for seasonal bioaccumulation and human health risk assessment. According to the findings, Fe and Zn were the most accumulative and element concentrations changed considerably (P < 0.05) between seasons and species. Daily, weekly, monthly intake and target hazard quotients of the trace elements were estimated and compared with maximum limits. The results revealed that consuming these bivalve molluscs from the southern Marmara Sea could be considered safe for human consumption. Nevertheless, further monitoring is needed in order to better follow the development in time of elemental pollution due to increasing environmental pressure on the Marmara Sea basin, together with research on other different bioaccumulative organisms. [ABSTRACT FROM AUTHOR]

In the Western High of the Sea of Marmara, where pervasive gas hydrate and hydrocarbon gas seepage occurs, late Pleistocene-Holocene sediments are composed of a lower lacustrine and an upper marine unit. The sedimentary evolution, gypsum formation and carbonate anomaly, under the complex sedimentary environment at cold seep sites on the Western High, have not been systematically well explained. The transition from the lacustrine to marine unit occurs at around 7.5 m below the sea floor (mbsf), with a sulfidization front present in the lacustrine sediments just below it, and the marine unit includes a sapropel layer between 5.20 and 7.20 mbsf. The sedimentary sequence is characterized by authigenic minerals including pyrite, carbonates, and gypsum in the upper 0.50 mbsf, corresponding to the present-day sulfate-methane transition zone (SMTZ) near the seafloor. Mineralogical, chemical and isotopic compositions (13C, 18O, 34S, 26Mg) of the sediments in the core studied show their close relationship with intensive sulfate-driven anaerobic oxidation of methane (AOM) and other hydrocarbons. The dissolution of carbonate, related to the gas and oil migration, and organic matter enrichment might be the main cause of carbonate deficiency in the sapropel unit. Heavy carbon isotopic composition (δ13C Carb = 6.98‰) of carbonate at 4.30 mbsf implies that the carbon might be the residual by-product of subsurface biodegradation of seeping petroleum. The formation of secondary gypsum and partial dissolution of carbonate in the Sea of Marmara is commonly considered of being associated with the aerobic oxidation of pyrite. However, the euhedral authigenic gypsum studied might be with different origins, possibly including anaerobic oxidation of Fe-sulfides, carbonate deficiency in the sapropel unit and AOM. Gypsums below SMTZ are with the size of hundreds of microns. Linear pits and grooves are developed on these gypsum surfaces, probably due to corrosion by the methane-rich fluid of latest hydrocarbon seepage. Platy hexagonal gypsum in SMTZ, without any corrosion on crystal surface, might be associated with the changing flux of the acidic composition (e.g. CO 2) in the seepage. Depleted-26Mg by about 1‰ in the SMTZ might be caused by the upward seepage of hydrocarbons. Magnesium isotope of authigenic carbonate could be a valid proxy for the recognition of SMTZ in a hydrate geo-system. • Authigenic gypsums in the sediments of Sea of Marmara are recognized with several origins. • Sedimentary environments in geological history on the Western High are studied. • Geochemistry of Mg isotope of carbonate at seeping site is related to anaerobic methane oxidation. • A model about the formations of authigenic minerals at a cold seep site MRS-CS-13 is proposed. [ABSTRACT FROM AUTHOR]

The mucilage event witnessed in the Sea of Marmara in 2021 has emerged as a prominent environmental concern, capturing public attention due to its detrimental effects on ecological, economic, and aesthetic dimensions. Addressing the multifaceted impacts of mucilage demands a nature-centric scientific approach, given its global ramifications spanning economy, public health, international relations, and tourism. Consequently, this study sought to explore alternative approaches for the removal of pathogenic enteric bacteria associated with mucilage occurrences, diverging from conventional methodologies. Specifically, the primary objective was to assess the efficacy of rhamnolipid and a bacteriophage cocktail in mitigating the proliferation of enteric pathogens within mucilaginous environments. During the study, 91 phage isolations were obtained from 45 water samples taken and 10 phages were selected for the broad host range and because of the efficacy tests, a phage cocktail was created with 5 phages. It was found that the mixture of rhamnolipid, phage cocktail and rhamnolipid-phage cocktail reduced bacterial load by 7–9 log 10 , 9–12 log 10 and 9–11 log 10 respectively under laboratory conditions. When the study was carried out in seawater, reductions of 4–5 log 10 , 3 log 10 and 4 log 10 were achieved. This study has shown that the combined use of rhamnolipid, phage cocktail and rhamnolipid-phage cocktail can be considered as the most effective natural solution proposal for reducing bacterial load, both in laboratory conditions and in sea surface water. [Display omitted] • Mucilage proliferation in Marmara Sea is a key marine ecosystem concern. • Addressing mucilage dilemma requires nature-based methods and tech advancements. • Assessing rhamnolipid & phage combo for mucilage pathogens is a viable strategy. • Molecular studies should be prioritized to reduce environmental impact of mucilage. [ABSTRACT FROM AUTHOR]

Copyright of Ege Journal of Fisheries & Aquatic Sciences (EgeJFAS) / Su Ürünleri Dergisi is the property of Ege Journal of Fisheries & Aquatic Sciences (EgeJFAS) / Su Urunleri Dergisi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The aim of this study is to determine the phytoplankton species found on the shores of Burgaz Island and the basic ecological variables that affect their seasonal distribution between May 2013 and February 2014. Water samples were collected from four stations at six different depths and plankton samples were gathered horizontally and vertically. The analysis of phytoplankton community composition revealed 101 phytoplankton taxa belonging to five classes. As a result of the study, two taxa belonging to the Dinophyceae (Corythodinium frenguellii and Gonyaulax scrippsae) were new records for Turkish coastal waters. Additionally, a taxon belonging to Dinophyceae (Pronoctiluca pelagica) and a taxon belonging to Bacillariophyceae (Nitzschia reversa) were new records for the Sea of Marmara. Prorocentrum micans, was the dominant species throughout all sampling periods. During the study, the highest phytoplankton abundance was observed at 0.5 m depth in May 2013 (138,500 cells l−1) and February 2014 (52,620 cells l−1). Primary ecological variables, such as temperature (9.0–21.5 °C), salinity (15.23–37.22‰) and dissolved oxygen (4.89–15.84 mg l−1), were recorded on each sampling occasion. In addition, nitrite + nitrate–N (NO2 + NO3–N) (0.01–7.37 μg-at N l−1), phosphate (PO4–P) (0.05–51.95 μg-at P l−1) and silicate (SiO4–Si) (0.01–0.20 μg-at Si l−1) concentrations were measured. Chlorophyll a and suspended material values ranged between 0.01–3.17 μg l−1 and 10.0–61.5 mg l−1, respectively. Spearman's rank correlation was used to determine the relationship between phytoplankton species and ecological variables, and Bray–Curtis analysis and Euclidean distance were applied to bring out the similarity between stations. [ABSTRACT FROM AUTHOR]

Copyright of Adiyaman University Journal of Science & Technology / Adıyaman Üniversitesi Fen Bilimleri Dergisi is the property of Adiyaman University, Institute of Science / Adiyaman Universitesi Fen Bilimleri Enstitusu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Marmara is the most highly trafficked region in Turkey in terms of seaway and highway transport congestion. The transport mode-based CO2 emissions budget for the region needs to take more environmentally friendly measures. In this study, 13 ro-ro and ferry lines (RFLs) are evaluated in the Sea of Marmara to compare ship-generated CO2 emissions with road transport as if the carried vehicles had used the highway instead of transport by RFL. Additionally, this study revealed the management strategies for CO2 emissions reduction for both transport modes under current conditions. The total CO2 emissions budget of 13 RFLs in the Sea of Marmara is higher than the potential CO2 emissions of their carried vehicles. Using the methods of Entec UK Ltd and Trozzi and Vaccaro, the amount of CO2 emissions generated by the RFLs is 204,470.99 and 170,459.85 t/year, respectively. The potential CO2 emissions of road vehicles carried in 2017, 2018 and 2019 are computed by applying Tier 1 methods as 121,690.54, 106,844.89, and 100,921.95 t/year, respectively. It is observed that shifting trucks from the highway to the seaway contributes to a reduction of the yearly CO2 emissions budget generated from the transport sector to provide sustainable transportation management in the region.

The present research study investigated the catch-per-unit-effort (CPUE, kg/h) and biomass of Par-apenaeus longirostris in consideration of three parameters, i.e. seasons, regions, and depth levels. Beam trawls were used to collect the specimens at a total of 229 sampling stations in the Sea of Marmara between September 2011 and July 2014. In the Sea of Marmara, the mean CPUE of P. longirostris was calculated to be 8.4±0.5 kg h-1 , and the mean biomass to be 354 kg/km-2. The mean CPUE value was at its highest in summer and autumn, and the lowest was observed in winter and spring. The by-region mean CPUE value of P. longirostris was the highest in the northern Sea of Marmara (14.3±1.9 kg h-1), and the lowest was detected in the south (3.6±1.0 kg h-1). The highest biomass value was found at a depth of 50-100 m, in the northern Sea of Marmara, while the lowest was calculated in the southeastern Sea of Marmara.

Jellyfishes, which are one of the most important consumers in marine ecosystems, may have detri-mental effects on fish stocks that have economic value. Therefore, identifying and monitoring jelly-fish presence is important. We observed four individuals of symbiotic rhizostome scyphozoan Cot-ylorhiza tuberculata in the vicinity of the Princes’ Islands Archipelago, in the Northeast Sea of Marmara, Turkey in September 2020. Although this species is a common member of gelatinous plankton in the Mediterranean Sea, the present study is the first record from the Sea of Marmara.

Abnormalities of shape, color or body deformities such as lack of swim bladders or any parts of the body are an unexplained issue for many fish species. There is a gap of knowledge regarding their causes. Generally, it is an important problem in the rearing technique in aquaculture management due to the high economic consequences. The morphological abnormalities occur in marine fishes as well. Missing dorsal spines or rays, scale disorientation, jaw deformities, eye deformations and the lack of some parts of the body are within the context of abnormality. In the present study, the body abnormality observed in a specimen of European hake (Merluccius merluccius Linnaeus, 1758) missing its right eye which was caught by a fisherman in the Marmara Sea on 13 October 2020, and its causes are reported and discussed. Further studies are needed to correlate the wild fish anomalies caused by pollution. [ABSTRACT FROM AUTHOR]

Dentex maroccanus Valenciennes, 1830 and Gobius couchi Miller & El-Tawil, 1974 were captured from the Marmara Archipelago in May 2022. Both species are new additions to the Sea of Marmara fish fauna. According to the available data, we assume D. maroccanus to be recently introduced to the region, while G. couchi may have been overlooked in previous studies due to its cryptogenic lifestyle. [ABSTRACT FROM AUTHOR]

Within the scope of this paper, seismic reflection and bathymetry studies were carried out in the shallow marine area forming the westernmost part of the Tekirdağ Basin using the R/V Selen Research Vessel within the MTA Marine Research Department. In the study area, ~ 500 km length bathymetry data and ~191 km shallow seismic profiles ( 41 lines) were collected. By means of the data, tectonic structures and deformation textures of the North Anatolian Fault System (NAFS) in the marine area of Gaziköy were examined. As a result of the processing and interpretation of the seismic sections, compression structures occurring due to the SW rotation of the NAFS in the study area, the morphology of the Ganos depression that formed as a result of faulting and also three different stratigraphic units were distinguished. These units are separated from each other by distinct unconformity surfaces and each unit presents different deformation structures. One of the most significant results obtained from the seismic data is that the unconformity surface that separates the current sediments of the seafloor from the older units is represented by the overlapping structures indicate sea level changes. It has been assessed that this situation occurred as a result of the erosional process developed during sea level fall.

Excluding the jellyfish from the bunt-end is a common slipping process used in the Sea of Marmara purse seine fishery. For this aim, a sheet of netting piece, larger mesh size and thicker diameter, is rigged on the bunt-end of the purse seine net. The jellyfish mass on the netting piece are slipped by rolling over the headline (floating line) after partially hauling or drying-up the net while it is still in the water. In this study, the catch amount of this slipping was roughly estimated with the introduction of the slipping process only used by the purse seiners in the Sea of Marmara. There were eight successful purse seine operations conducted between 8 and 11 September 2018 in depth ranged 77 to 677 m. The percentage of landed species versus to jellyfish varied between 23% and 85%. The mean landed anchovy amount is 4379 (3756.6) kg for per operation. The mean slipped amount of jellyfish is 3812.5 (2404.4) kg. However, both anchovy (99.8%) and jellyfish (96.3%) are the vast majority species that landed and slipped, respectively. In the operations totally 100 boxes of anchovy (1180 kg) unintentionally was slipped with the jellyfish. In addition, two sharks with larger size were slipped to the sea as alive over the floating line of the net. Although slipping practised rarely in Turkey, all the purse seiner in the Sea of Marmara have to use the adapted slipped process to get rid of jellyfish. However, there are no records and scientific findings regarding slipped amount of the jellyfish. For this reason, this study is important to presented preliminary results regarding amount of the jellyfish. In conclusion, this study is extended completely the Sea of Marmara practised to understand the dimensions of jellyfish amount and slipping process.

The article is devoted to the early phase of the career of Martin Eric Nasmith (1883–1965) and is an attempt to summarise his achievements during three underwater patrols in the Dardanelles and the Sea of Marmara in 1915. Those missions brought him the appellation of the most effective British submariner of WW1. In Anglophone historiography, all the books and articles related to this subject constitute a one-sided narrative based solely on British sources. Thus, the author has made the first attempt in western historiography to compare the British and Turkish points of view. Although a few such efforts have been made in Tur- key, their results are not widely known to western historians, and in some cases, they raise objections. The decision to take up this challenge came from an awareness that Nasmith’s view of the situation at the moment when he was personally observing the effects of his attacks could not be complete and entirely objective. He could not have known that some of the vessels he had sunk in shallow coastal waters were salvaged by the Turks and restored to service. The article gives detailed coverage of the attacks conducted by Nasmith on Ottoman warships, steam-powered merchant ships and land targets, during all three patrols of the “E11” submarine. As a result of his research, the author was able to draw attention to the fact that the results of “E11”’s second patrol were incomparably more favourable than those of the first one (for which Nasmith was awarded the Victoria Cross), both in terms of losses inflicted on the Ottoman Navy and on the transport fleet. In the case of the latter, the total tonnage of definitively sunken steam-powered vessels was more than 470 percent higher. While Nasmith claimed that he had sunk at least 122 Ottoman vessels during all three patrols, Turkish sources indicate that the total number of warships and steam-powered transport ships definitively destroyed by him did not exceed fifteen.

Copyright of Studia Maritima is the property of University of Szczecin Press / Wydawnictwo Naukowe Uniwersytetu Szczecinskiego and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The study deals with the growth pattern, mortality, and reproduction of common sole, Solea solea (Linneaus, 1758), from the Sea of Marmara (Turkey). A total of 580 fish specimens were sampled monthly from October 2017 to September 2018. The total length of all sampled individuals ranged from 11.1 to 29.5 cm, corresponding to ages from 1 to 3 years. The length–weight relationship was expressed as W = 0.022 TL2.6838, where the slope indicated negative allometric growth. Growth parameters were L∞ = 33.7 cm, k = 0.48, and t0 = −0.18 for all samples. A seasonally oscillating growth model, indicating the amplitude of oscillations, revealed an important seasonal growth pattern. Total, natural, and fishing mortality rates were calculated as 1.42, 0.47, and 1.01, respectively. The exploitation ratio (E = 0.68) indicates that the fishing pressure on the common sole in the Sea of Marmara was high. The sex ratio (♀/♂) was 1.18. The gonadosomatic index (GSI) for females showed that two main spawning seasons were observed: one in spring (May) and one in autumn (September–October). Sizes at the onset of sexual maturity were estimated for both females and males at 21.6 and 18.6 cm, respectively. [ABSTRACT FROM AUTHOR]