The Working Group on Marine Litter (WGML) aims to provide scientific guidance for the inter-national harmonisation of monitoring data on seafloor litter and microlitter, acting as a knowledge hub for other international organisations and supporting the ICES Secretariat.
WGML activities focus on reviewing and assessing the quality and potential uses of current data in the ICES DATRAS (Trawl Surveys) and DOME (Marine Environment) databases, while also reporting on new developments in quality assurance for marine litter and microplastic monitor-ing in Europe and providing information on relevant proficiency testing schemes. To validate the ICES manual for seafloor categorisation and accompanying photo guide, a seafloor macrolit-ter proficiency test was created to assess classification accuracy and the usability of ICES manual, helping improve seafloor litter categorization and data collection methodologies. In addition, WGML reviewed and approved a new microplastic and litter data submission format, splitting it into four compartments: water, sediment, biota, and seafloor litter. The format was stress-tested and aligned with EMODnet standards, with recommendations for improved data report-ing and integration with EMODnet microlitter data flows. WGML, in collaboration with ICES Marine Chemistry Working Group (MCWG) and Working Group on Biological Effects of Con-taminants (WGBEC), contributed to an A1-publication evaluating knowledge gaps on plastic ad-ditives. Based on an online stakeholder survey, the publication highlighted key issues in as-sessing the risks of plastic additives, particularly data gaps in production volumes, use, persis-tence, bioaccumulation, and toxicity. A new focus area for WGML is evaluating innovative mon-itoring methods for both macro- and microlitter. A review of emerging underwater technologies for seafloor litter, including sonar systems and optical sensors, revealed their potential to en-hance monitoring capabilities. However, many of these tools are still in early development stages.
Looking ahead, WGML term 2025–2027 will focus on integrating these advanced technologies, working toward a shift from traditional methods to more sustainable, effective monitoring solu-tions for marine litter. Other priorities are the quality assurance processes for data acquisition and the optimisation of the usability of the ICES litter category list.