Assessing and monitoring marine litter
Technical reports
D.2.2.1: Literature review – State of the art. Microplastic sampling methods in natural water bodies
Responsible Partner: IEO
Date: October 2025
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Description: This deliverable presents a literature review – state of the art on microplastic sampling methods in marine and freshwater environments. It analyses representative sampling strategies, the use of clean equipment and blank controls, and the importance of periodic sampling. Furthermore, it highlights the need for standardized methods and harmonised guidelines to ensure the reliability and comparability of results.
D.2.2.6: Report on the potential of imagery coupled with deep learning solutions to monitor strandings of large microlitter on the coastline
Responsible Partner: CEDRE
Date: November 2025
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Description: Strandings of mesoplastic fragments (0.5-2.5 cm) and large microplastics (1-5 mm), including plastic pellets, are regularly observed on beaches of the Atlantic area. The objective of the Activity 2 of Free LitterAT work package 2 is to improve and enhance capability for microlitter detection and monitoring. In this context, the task 4 includes the development and testing of methods based on imagery coupled or not, with artificial intelligence to quantify large microlitter (1-5 mm) strandings on the coastline, in the context of the EU-recommended monitoring methodology. To feed this task, the work conducted by CEDRE with the support of IFP Energies Nouvelles (IFPEN), is divided into two parts. First, traditional imagery methods were tested to automatically quantify large microplastics in samples pre-treated in the laboratory to retain only the particles targeted. Samples used for the methods testing were real field samples collected using the EU methodology, on the French Atlantic coastline. Two separate software tools were tested to assess the potential of traditional image processing techniques to automatically count and characterise particles morphology on sample photographs. Secondly, a deep learning-based solution was tested to monitor large microplastics directly in the field on one of the Atlantic beaches of the French monitoring program (Le Stang, Brittany, France). Overall, while further studies and improvements are needed, the tested methods have a good potential to optimise the monitoring of large microplastics (1-5 mm) in the context of a routine beach monitoring using the EU-recommended methodology, such as the one conducted on the French coastline.
Publications
Entangled ecosystems: the impact of macroplastic litter on Mytilus galloprovincialis communities in northwestern Spain
Responsible Partner: IEO
Date: October 2025
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Description: This study highlights that macroplastics can subtly alter the functionality of mussel beds without dramatically affecting the diversity of the associated fauna. These insights underscore the need to assess physical interactions of organisms with plastic litter also at the community level.
Are fish larvae contaminated before they start eating? First evidence of microplastic contamination in the yolk-sac of wild fish larvae
Responsible Partner: CIIMAR
Date: September 2025
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Description: This novel study provides relevant insights into MPs contamination processes, showing that MPs contamination can occur early in the life cycle of fishes, from hatching onwards. Furthermore, the presence of MPs in fish larvae appears to be more dependent on the MPs that are in higher abundance in the surrounding water than fish larvae preferences or ecological guild, physical characteristics, or even the ontogenetic developmental stage.
Remote sensing and image analysis of macro-plastic litter: A review
Responsible Partner: ARDITI-MARE
Date: August 2025
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Description: The article discusses how remote sensing and artificial intelligence are being used to detect and quantify plastic litter in rivers, coastal areas, and oceans. It reviews recent studies employing drones, satellites, cameras, and other sensors for this purpose, analyzing their methods and limitations, and highlights the need to standardize metrics and protocols to enable global comparability of results. It also proposes the creation of open-access platforms where various stakeholders can share images and data to improve monitoring and policymaking on plastic pollution.
Assessing Microplastic Contamination and Depuration Effectiveness in Farmed Pacific Oysters (Crassostrea gigas)
Responsible Partner: CIIMAR
Date: July 2025
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Description: This study aims to address some of these knowledge gaps by investigating the MP levels in estuarine farmed oysters and evaluating the factors influencing contamination levels. Additionally, it seeks to assess the effectiveness of depuration as a potentialmitigation strategy for MP removal.
The role of marine debris as a vector, dispersal agent, and substrate for non-indigenous species on Oceanic Islands (Northeast Atlantic)
Responsible Partner: ARDITI-MARE
Date: March 2025
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Description: This study underscores the urgent need for standardized monitoring, stakeholder engagement, and proactive marine debris (MD) management strategies to mitigate non-indigenous species (NIS) introductions and protect sensitive marine ecosystems like Macaronesia from the ecological risks of biological invasions.
Assessment of seabed litter at Concepción Seamount (Canary island) using a remotely operated towed vehicle
Responsible Partner: IEO
Date: February 2024
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Description: The study presents the first comprehensive assessment of marine litter pollution at the Concepción seamount, providing baseline information to improve the management of this major threat to the ocean. The use of a remotely operated towed vehicle equipped with a camera is showed as a powerful tool to monitor marine litter and their interaction with biota. Most seafloor litter identified comes from fishing activities and mainly consists of lost fishing lines. This study provides strong evidences of the presence of litter in the seamount, which can be useful for effective management of the valued ecosystem of the Concepción seamount.