No longer just a pollution problem, marine debris is increasingly recognized as a vehicle for the global spread of non-indigenous species (NIS), with serious consequences for marine ecosystems. Floating plastics, discarded rope, derelict fishing gear, and other human-made litter not only harm marine life through entanglement and ingestion, they also serve as mobile habitats for a wide range of organisms. These "rafts" can carry barnacles, mussels, algae, and more across oceans, enabling species to survive journeys they would not normally complete. Once these organisms arrive in new environments, some may become invasive, outcompeting native species and disrupting local biodiversity.
ICES Working Group on Marine Bioinvasions (WGBIOINV) experts work together to understand the spread of marine organisms via human activity, and the group has recognized this emerging pathway as a critical concern, dedicating one of its specific objectives to investigate its role in the spread of NIS as part of the group’s broader work on marine biosecurity. This includes studying how marine debris acts as both a transport vehicle and a surface for organisms to grow on. The group's work also highlights major knowledge gaps, such as how different debris types, oceanographic conditions, and biofouling communities interact over time.
In 2025, WGBIOINV celebrated a key milestone as it published the first peer-reviewed paper directly arising from its work on this issue. The study, The role of marine
debris as a vector, dispersal agent, and substrate for non-indigenous species
on Oceanic Islands (Northeast Atlantic), published in Marine Pollution Bulletin, investigates the organisms colonizing debris found around remote islands such as Madeira, Portugal.
This study showed that marine debris can act as a vector for NIS to reach remote oceanic islands. “The findings can help inform early warning systems, targeted monitoring, and stronger marine biosecurity policies", says Joao Canning Clode, chair of WGBIOINV. “It was also an opportunity to engage local stakeholders—including birdwatching and whale-watching companies, fishers, and diving centres—who could play a key role in early detection and awareness.
Read "The role of marine debris as a vector, dispersal agent, and substrate for non-indigenous species on Oceanic Islands (Northeast Atlantic)," in Marine Pollution Bulletin.
Changing names
This ICES expert group has been in existence since 1970. Originally named the Working Group on the Introduction of Non-Indigenous Marine Organisms, it changed its name in 1980 to the Working Group on Introductions and Transfers of Marine Organisms (WGITMO) and, now in 2025, to the Working Group on Marine Bioinvasions (WGBIOINV).
