GESAMP  is an advisory body consisting of specialized experts nominated by the Sponsoring Agencies. Its principal task is to provide scientific advice concerning the prevention, reduction and control of the degradation of the marine environment to the Sponsoring Organizations. 

The GESAMP Working Group on Sea-based Sources of Marine Litter (WG 43) was formally established in April 2019 and is jointly led by FAO and IMO as Technical Secretaries with co-sponsorship support from UNEP.

The overall objective of WG 43 is to build a broader understanding of sea-based sources of marine litter, in particular from the shipping and fishing sectors, including the relative contribution from different sources and the range and extent of impacts.

WG 43 has also been mandated to work to build a more comprehensive understanding of specific types of sea-based sources of marine litter, and to guide interventions on these sources based on identified priorities, drawing upon the expertise of FAO, IMO, UN Environment Programme (UNEP) and other relevant organizations and experts. 

WG 43 operated through two phases. During the first phase, the WG was requested to address two concurrent work-streams: (1) an overarching scoping study, which will generate the information required by IMO for implementation of its Action Plan to Address Marine Litter from Ships and help identify priorities within this overarching scope; and (2) a specific focus on the science underlying ALDFG as a particularly damaging form of sea-based marine litter, in order to inform and advance interventions. Their first report was published in October 2021 and can be found here.

In September 2022, at the 49th annual session of GESAMP (London, United Kingdom), new Terms of Reference (ToR) in two concurrent work streams were approved : Work-stream 1 will support information requests of the Scientific Groups of the London Convention/Protocol (LC/LP) Parties that will help identify priorities for addressing LC/LP waste streams, ship coatings and abandoned vessels as sources of plastic in the ocean. Work-stream 2 will support information requests of FAO to further understand abandoned, lost and otherwise discarded fishing gear (ALDFG) as a source of ocean plastic, with a particular focus on methodologies for remediation, monitoring and reporting. The second report resulting from the new ToR is in review stage and is planned to be published in early 2026.