Monitoring the composition, sources and spatial distribution of seafloor litter in the Adriatic Sea (Mediterranean Sea) through Fishing for Litter initiatives.

Although the seafloor is an important sink for marine litter, its less accessible environment makes seafloor litter the least studied component. Nevertheless, detailed monitoring of its composition and spatial distribution is urgently needed to develop appropriate mitigation strategies in areas exposed to multiple anthropogenic pressures, such as the Adriatic Sea. Commercial fisheries such as bottom trawls can serve as an opportunistic platform for collecting data on seafloor litter and help researchers in addressing the lack of data through Fishing for Litter initiatives. In this study, the crews of twelve trawlers from two Italian Adriatic ports collected seafloor litter as part of their Fishing for Litter initiatives. In addition to the classical scheme, the collected litter was sorted on board into different bags, and speed, duration and geographical coordinates of each haul were recorded to allow an assessment of both densities and spatial distribution. More than 600 kg of litter was removed from the seafloor by the fishers in approximately 1 month and characterised by the researchers on the docks. Most of the found items were made of synthetic polymers and related to packaging, fisheries and aquaculture activities. Abandoned, lost or discarded fishing gear and mussel nets were identified as of particular concern in the maritime compartment of Chioggia and Civitanova Marche, respectively. Three hotspots for marine litter were identified: near the Venice lagoon, in the centre of the northern basin and at greater depth in the central Adriatic. This study provides a detailed picture of the spatial distribution and composition of seafloor litter in the areas studied and highlights the importance of increased cooperation between fishermen and scientists to improve the identification of hotspots and sources while removing marine litter from the seafloor and raising awareness of the problem.

Levels of perfluorinated acids (PFCAs) in different tissues of Lepidochelys olivacea sea turtles from the Escobilla beach (Oaxaca, Mexico).

Lepidochelys olivacea is the most abundant and globally distributed sea turtle species in the world and thus, monitoring this species for persistent organic pollutants, such as perfluorinated chemicals, is fundamental for their protection. This study was the first to evaluate the occurrence of five PFCAs (PFOA, PFNA, PFDA, PFUnA, PFDoA) in liver and blood samples of Olive Ridley turtle population from the Escobilla beach (Oaxaca, Mexico). PFDA and PFUnA were the predominant PFCs in blood samples (detected in 93% and 84% of samples, respectively) and were also present in the highest concentrations. Liver samples showed higher PFCA concentrations than whole blood samples, with PFNA and PFDA the most abundant PFCs congeners in liver samples, detected in 65% and 47% of the samples, respectively. The measured levels of contaminants in the blood samples of Lepidochelys olivacea sea turtles were compared to the levels reported in the literature for other turtle species. While linear significant correlations between PFNA, PFDA and PFUnA concentrations in blood samples and curved carapace lengths were determined, no correlation was found for PFOA, supporting the hypothesis that sea turtles could have a higher ability to eliminate this perfluorinated chemical from their blood than other PFCAs. However, we do not know if the concentrations are species or sampling areas dependent.