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Öğe Assessment of spatiotemporal distribution of benthic marine litter for the southern Black Sea coasts of Türkiye(Pergamon-Elsevier Science Ltd, 2025) Dagtekin, Murat; Kasapoglu, Nazli; Ok, Meltem; Ilhan, Salih; Buyukdeveci, Ferhat; Erik, Gokhan; Ozsandikci, UgurThis study investigates the prevalence and characteristics of benthic marine litter along the southeastern Black Sea coast. A two-year seasonal trawling survey (2017-2018) was conducted between & Ccedil;ayagzi Cape and & Uuml;nyeTas,kana Cape across three depth ranges to evaluate litter density and composition in accordance with the Marine Strategy Framework Directive (MSFD). The results indicate an average litter density of 48,744.69 +/- 7543.02 items/km2 and 151.35 +/- 14.04 kg/km2, with plastic accounting for over 50 % of the total debris. Statistical analyses of seasonal and depth variations revealed no significant differences in overall litter density; however, plastic items such as bags (36.4 %) and bottles (18.97 %) predominated consistently. The findings highlight the significant contribution of Turkey's coastline to regional marine litter, driven by intensive urban and industrial activities, further compounded by riverine inputs from major rivers discharging into the Black Sea. The study underscores the urgency of enhanced international collaboration and the development of comprehensive regional strategies to combat marine pollution. Insights into the distribution and density of benthic marine litter are critical for informing effective policy measures and raising public awareness to address the pervasive issue of marine litter in the Black Sea basin.Öğe Distribution and composition of seafloor marine litter in the southeastern Black Sea(Turkish Marine Research Foundation-Tudav, 2020) Kasapoglu, Nazli; Dagtekin, Murat; Ilhan, Salih; Erik, Gokhan; Ozsandikci, Ugur; Buyukdeveci, FerhatThis study was conducted to investigate seafloor marine litter abundance between Samsun (Yakakent) and Hopa within the scope of Integrated Marine Pollution Monitoring Project (CSB/CEDIDGM-TUBITAK/MAM) in summer 2019. Totally, the trawl hauling operations were successfully performed in 30 stations. The works were done according to the MEDITS protocol: sampling was done at 3 different depths (0-20 m, 20-50 m and 50-100 m), marine litter was classified in 9 categories. At all sampling stations marine litter was assessed by weight and amount. The most common marine litter group was L2 tire/rubber by weight (53%) and amount (67%) when L1 plastic group - 25% by weight and L5 fabric and natural fibres - 12% by amount. Especially in the L2 group, the car and truck tires were dominated in weight of CB5 (Trabzon- Surmene) and CB3 (Trabzon) stations.Öğe Effect of a fishing closure on Chamelea gallina stocks along the Turkish coast(Cambridge Univ Press, 2023) Dagtekin, Murat; Dalgic, Goktug; Erbay, Murat; Akpinar, Ilkay Ozcan; Aydin, Mehmet; Ozdemir, Süleyman; Karayucel, SedatThe striped venus clam Chamelea gallina (SVE), plays an important role as an infaunal filter-feeder in the ecosystem, besides an important economic role in the Black Sea coasts of Turkey. It is caught using hydraulic dredge boats, then processed, and the final product (frozen meat) is exported to EU countries. SVE fishing requires a special licence and regulations. Also, SVE beds were closed to fisheries for the recovery of stocks for 2 years. In the study, SVE beds were investigated during the closed season over two years to assess stock density. Additionally, the number of macrobenthic species that share the same habitat as the SVE was determined. The sampling area was divided into five sub-areas and four strata by depth and then stratified random sampling was applied to collect data. In 2011, SVE stock sizes in the sub-areas were 11,723.58 +/- 5167.262 tons (Cide), 35,082.94 +/- 27,510.95 tons (Inebolu), 10,077.05 +/- 4970.68 tons (Turkeli), 3304.36 +/- 3215.1 tons (Ayancik) and 1431.3 +/- 1703.5 tons (Sarikum). In 2012, these estimated stocks were 13,820.41 +/- 6977.86 tons, 34,841.94 +/- 14,623.71 tons, 8148.27 +/- 5006.74 tons, 3420.72 +/- 3093.67 tons and 2023.74 +/- 2832.63 tons, respectively. However, the estimated SVE total biomass did not change significantly during the period when the fields were closed (P > 0.05). The results indicate that length-weight relationship parameters varied of b from 2.9011-2.9072 in two years. Shell damage during fishing, environmental factors, food competition and consumption by the main predator all have a significant impact on stock densities, and changes occurring in these conditions should be considered in fisheries management.Öğe Length-weight relationships of 28 fish species caught from demersal trawl survey in the Middle Black Sea, Turkey(Tubitak Scientific & Technological Research Council Turkey, 2022) Dagtekin, Murat; Genc, Yasar; Kasapoglu, Nazli; Erik, Gokhan; Misir, Devrim Selim; Ilhan, Salih; Ok, MeltemThis study provides updated the length-weight relationships and Fulton's condition factor of 28 fish species belonging to 23 families from the Black Sea. Samples were collected along the depths between 0-100 meters by demersal trawl surveys conducted seasonally from May 2017 to September 2019. A total of 83,885 specimens were collected. The length-weight relationships and Fulton's condition factor, minimum, maximum and mean lengths, total weights, descriptive statistics, and growth type were provided for all the species. The results indicate that LWR parameters of b varied from 2.2039 to 3.737 and Fulton's condition factor varied between 0.004 and 1.18. These findings could be useful for monitoring and management of sustainable fisheries and habitat health.Öğe Modelling growth and population parameters of the invasive gastropod Rapana venosa (Muricidae) in the Black Sea using statolith-based ageing(Springer Japan Kk, 2025) Basusta, Nuri; Durrani, Omerhan; Bat, Levent; Basusta, Asiye; Dagtekin, Murat; Seyhan, KadirThe veined rapa whelk, Rapana venosa, is the first invasive non-indigenous species to attain significant commercial importance in the industrial fisheries of the Black Sea. In this study, statoliths of R. venosa were used for age determination. Samples were collected monthly from the eastern Black Sea using a standard commercial dredge at three major fishing areas: Sinop, Samsun, and Trabzon. Four growth models (logistic, Gompertz, asymptotic exponential, and von Bertalanffy) were fitted to describe the relationship between age and shell length, with the von Bertalanffy growth function providing the best fit. A one-way analysis of covariance (ANCOVA) revealed no significant sexual dimorphism in growth curves at any station; however, significant temporal and spatial variations were detected, with the highest estimated growth rates in autumn and the most pronounced spatial differences in winter and spring. Furthermore, the shell length-weight relationship exhibited significant sexual dimorphism, along with notable spatial variation. These findings underscore the importance of considering growth model selection, sex, spatial (fishing area), and temporal factors when estimating growth parameters. This study provides the first direct estimates of age and growth for R. venosa in the Turkish Black Sea using statoliths, thereby establishing reliable parameters for its monitoring and sustainable management.Öğe Population abundance and growth parameters of an exotic bivalve species, Anadara kagoshimensis, in the Southwestern Black Sea(Tubitak Scientific & Technological Research Council Turkey, 2023) Dagtekin, Murat; Dalgic, Goktug; Erbay, Murat; Akpinar, Ilkay Ozcan; Aydin, Mehmet; Ozdemir, Suleyman; Cebeci, AyseBlood cockle (Anadara kagoshimensis ) is an Indo-Pacific species that later entered the Black Sea. The abundance of A. kagoshimensis, which is not subjected to commercial fishing, is important in terms of food competition with other bivalvia species. Baby clam (Chamelea gallina) together with the A. kagoshimensis are dominant bivalve species found in the sandy and muddy areas off the coastal waters of the Black Sea. In this study, specimens of A. kagoshimensis have been recognized by morphological analysis and also confirmed by molecular characterization. Furthermore, the abundance and growth parameters of A. kagoshimensis were investigated in the Southwestern Black Sea. Blood cockles were sampled between February 2011 and December 2012, seasonally. According to the Von Bertalanffy Growth Parameters (VBGP) the results were L infinity = 81.96 mm, K = 0.32 year-1, t0 = -0.22 year, and nonseasonal L infinity = 84.32 mm, K = 0.31 year-1, t0 = -0.21, WP = 0.65, ts = 0.15. The growth pattern showed the slope [b] = 2.96-3.01 in 2011 and 2012. The stock size was estimated according to two different years in 5 different subareas (Cide, Inebolu, Turkeli, Ayancik, and Sarikum) and by 4 different strata (0-5 m, 5-10 m, 10-15 m, and 15-20 m). Considering subareas, the A. kagoshimensis population in all subareas increased significantly in a single year. Compared to other regions, Inebolu was the main highly distributed area of the A. kagoshimensis, and also the estimated stock size was the highest in the region. Due to food competition with other commercial species (mainly Chamelea gallina) A. kagoshimensis is an ecology important species for the Southern Black Sea habitats. It is aimed to make contributions to Good Environmental Status (GES) and fisheries management in the region.Öğe Spatial patterns of zooplankton communities along the Sinop-Samsun transect(Elsevier, 2026) Ustun, Funda; Uygun, Orcin; Bat, Levent; Dagtekin, MuratThis study examined the zooplankton composition, abundance, and biomass distribution, as well as their relationship with environmental variables at 17 stations between Sinop (T & uuml;rkeli) and Samsun (Yakakent) in the Turkish Black Sea in June 2023. The mean zooplankton abundance and biomass were 705.85 +/- 556.02 individuals (ind.)/m3 and 39.53 +/- 37.33 mg/m3, respectively. The copepods were the most dominant taxa in terms of abundance and biomass, followed by Noctiluca scintillans. Coastal shallow stations were mainly characterised by higher abundances of Paracalanus parvus and Acartia clausi, whereas offshore deeper stations were associated with Pseudocalanus elongatus, Oithona similis and Parasagitta setosa. Zooplankton abundance and biomass exhibited marked spatial variability along the transect. The abundances of Pleopis polyphemoides and meroplankton groups were affected by temperature and salinity changes. These findings indicate that the zooplankton community structure exhibits spatial variation and is sensitive to environmental variables.Öğe Summer ichthyoplankton assemblages and their environmental drivers in the Sinop Peninsula, Southern Central Black Sea(Elsevier, 2026) Uygun, Orcin; Bat, Levent; Dagtekin, Murat; Ustun, FundaThis study examines the composition and spatial distribution of ichthyoplankton assemblages in the central southern Black Sea, with a focus on the Sinop Peninsula. Ichthyoplankton samples were collected in June 2023 from 17 stations, and a total of 17 taxa belonging to 13 families were identified. Eggs of Engraulis encrasicolus, Merlangius merlangus, and Trachurus mediterraneus were the most abundant among ichthyoplankton, while larvae of Gobius niger and Diplodus annularis were dominant. The Shannon-Weaver index (H ') varied notably among stations, peaking at 2.32 in the easternmost site. Multivariate analyses (DistLM, dbRDA) revealed significant spatial differentiation in community structure, which was primarily associated with gradients in salinity, surface current velocity, and temperature. Environmental gradients are primary determinants of ichthyoplankton distribution, and mesoscale oceanographic processes significantly influence coastal ecosystem structure. Spatial segregation of spawning habitats, particularly between anchovy and horse mackerel, reflects distinct speciesspecific responses to salinity and current velocity in the Black Sea. This study provides a comprehensive description of the structure of the ichthyoplankton assemblages during the post-rainfall period, thereby establishing an important foundation for assessing the potential impacts of short-term meteorological disturbances on sensitive marine ecosystems.Öğe Summer ichthyoplankton assemblages and their environmental drivers in the Sinop Peninsula, Southern Central Black Sea (vol 94, 104769, 2026)(Elsevier, 2026) Uygun, Orrin; Bat, Levent; Dagtekin, Murat; Ustun, Funda[No abstract available]
