Browsing by Author "Karadurmus, Ugur"

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Distribution and Species Richness of Seagrass Meadows in the Sea of Marmara
(Elsevier Sci Ltd, 2025) Karadurmus, Ugur; Akkus, Mustafa; Sari, Mustafa
Comprehensive data on seagrass distribution and species richness in the Sea of Marmara (SoM) are absent from global seagrass mapping, hindering long-term monitoring and practical protection efforts for these vital meadows. This study aims to assess the species richness, spatial distribution patterns, and fundamental ecological aspects of seagrass meadows in the SoM, which serves as a crucial transition zone between the Black Sea and the Mediterranean Sea. The data set was obtained through a series of underwater surveys conducted between June and September 2024 at 140 surveyed stations, covering a total area of about 0.534 km2. Spatial and speciesspecific surface area (m2), cover percentage (%), and depth limits (m) of seagrass meadows were estimated from underwater records collected along line transects. Seagrass meadows constituted 51.9 % of the area surveyed in the SoM, covering an area of 0.277 km2. Results revealed a rich diversity of seagrass species within the SoM, identifying four species: Cymodocea nodosa, Posidonia oceanica, Zostera marina, and Z. noltei. C. nodosa was the most common species, occupying 82.8 % (0.230 km2) of the total surface area. The lower depth limits of seagrasses in the SoM were shallower than in other Mediterranean regions, with P. oceanica at 15.7 m and C. nodosa at 11.1 m. This limitation attributed to reductions in light penetration caused by high primary production and excessive pollution loads in the SoM. In conclusion, this dataset includes the first underwater observation-based mapping and identification of new areas for seagrass species in the SoM, contributing to distribution maps for the Mediterranean basin.
Distribution of Fan Mussel (Pinna Nobilis) Population in the Sea of Marmara
(Wiley, 2025) Karadurmus, Ugur; Akkus, Mustafa; Sari, Mustafa
The fan mussel (Pinna nobilis Linnaeus, 1758), a species severely affected by mass mortality events caused by Haplosporidium pinnae since 2016 throughout the Mediterranean Sea, continues to survive in isolated areas. The Sea of Marmara (SoM) represents one of the largest areas where alive fan mussels persist in high density. This study addresses critical data gaps by investigating the spatial distribution patterns and ecological characteristics of fan mussels in the SoM, providing a foundation for long-term monitoring and conservation initiatives. The dataset was generated through underwater surveys conducted between June and September 2024, covering approximately 35,000 m(2) across 144 stations along 1300 km of coastline in the entire SoM. Using non-destructive observational methods, 4748 fan mussels were recorded, 90.5% of which were alive. Spatial distribution patterns revealed distinct clustering, with an average density of 12.1 ind/100 m(2) and a maximum density of 122.1 ind/100 m(2) in specific hotspot areas. A strong association with seagrass habitats was evident, with 84.4% of the population found in these areas. The population structure was predominantly adult, with similar to 70% of individuals exceeding 10 cm in shell length, while recruits smaller than 10 cm represented 9.2%. The findings highlight the high density, low mortality rate and strong recruitment capacity of fan mussel populations in the SoM. This study provides the first comprehensive underwater observation-based mapping of fan mussel populations across the entire SoM and identifies new areas critical to their conservation.