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Updated: Mar 18, 2026
Data Collection on Marine Litter Ingestion in Sea Turtles and Thresholds for Good Environmental Status
Published on: May 18, 2019
Broad-scale distribution of marine benthic litter in shallow waters along the Turkish Aegean coast: a SCUBA-based
Yaşar Özvarol1, Barış Akçalı2, Erhan Mutlu3
1Maritime Faculty, Akdeniz University, Campus, Antalya, Turkey. ozvarol@akdeniz.edu.tr.
Purpose:
Marine litter, particularly benthic macro debris, poses persistent ecological and socio-economic threats to Mediterranean seafloor ecosystems. This study addresses critical knowledge gaps in the spatial distribution, composition, and accumulation characteristics of benthic litter along the understudied Turkish Aegean coastline.
Methods:
We conducted the first large-scale, depth-stratified SCUBA-assisted assessment of benthic macro litter across 326 stations along approximately 1600 km of the Turkish Aegean coast. Surveys were performed at six discrete depth levels (5-30 m) following MSFD and UNEP/MAP protocols. Litter items were classified into nine standardized material categories, and both abundance (n km-2) and mass (kg km-2) metrics were quantified. Multivariate statistical analyses (PCA and PERMANOVA) were applied to examine spatial and depth-related patterns in litter distribution.
Results:
A total of 822 litter items (4147 kg) were recorded, corresponding to mean values of 77.4 n km-2 and 383 kg km-2. Plastics dominated numerical abundance but contributed relatively little to total mass, whereas metal and concrete debris accounted for a disproportionate share of mass. Shallow stations (5-10 m) were characterized by higher abundances of lightweight litter associated with nearshore activities, while deeper stations more frequently contained heavier debris linked to maritime and aquaculture-related operations. Spatial variability in litter accumulation was primarily associated with material composition and localized human activities rather than broad administrative divisions.
Conclusion:
This study provides the first harmonized and policy-relevant baseline for benthic litter along the Turkish Aegean coast. The findings highlight the importance of integrating mass-based indicators alongside abundance metrics to better assess ecological risk and inform management strategies. SCUBA-assisted surveys are shown to be a robust and complementary approach for monitoring benthic litter in shallow, heterogeneous coastal environments within MSFD/UNEP-aligned frameworks.
