Bottom Trawling Impacts on Marine Benthic Ecosystems

Bottom trawling, the practice of dragging weighted nets across the seabed, constitutes one of the most pervasive anthropogenic disturbances of marine benthic ecosystems. The physical action of gear penetration and sediment ploughing disrupts habitat structure, reduces biodiversity and alters the composition and function of benthic communities. Sessile and long‐lived organisms, including sponges, corals and bivalves, suffer the greatest depletion, while opportunistic and short‐lived species tend to increase in relative abundance. Beyond direct biotic impacts, trawling accelerates sediment resuspension, redistributes organic matter and diminishes long‐term carbon storage in seabed sediments, thereby weakening the role of continental shelves in global carbon sequestration. Recovery trajectories vary widely: some soft‐sediment habitats may begin to rebound within months to years following cessation, whereas structurally complex or biogenic habitats require decades or longer to re-establish pre-trawl community states. The global extent of trawling and its cumulative pressure call for refined management approaches that balance fisheries production with the maintenance of ecosystem function and carbon-storage capacity.

Research from Nature Portfolio

Recent analyses have quantified how intensive trawling regimes undermine sedimentary carbon reserves in temperate shelf seas. High-resolution mapping of North Sea sediments reveals that areas trawled more than once per year manifest significant reductions in organic carbon relative to fine-mud content, whereas weakly trawled zones may show mixed gain–loss patterns owing to sediment redistribution. Three-dimensional physical–biogeochemical models attribute this net loss to the repeated mobilisation and export of carbon-rich mud layers, with recovery of carbon stocks proceeding more slowly than recolonisation by benthic fauna. Complementing this, assessments of non-fishing seabed disturbances demonstrate that trawling remains the dominant driver of carbon remobilisation on continental shelves, exceeding impacts from subsea infrastructure. These insights emphasise the need to integrate seabed carbon dynamics into marine management frameworks and to consider trawl-free refugia for climate-relevant ecosystem services.

Bottom Trawling Impacts on Marine Benthic Ecosystems publication trend

The graph below shows the total number of articles in bottom trawling impacts on marine benthic ecosystems across all publications each year (not limited to Nature Index journals).

Technical terms

Bottom trawling: A fishing method involving nets towed along the seabed, causing physical disturbance to sediments and organisms.

Benthic ecosystem: The community of organisms living on, in or near the seabed, including sedimentary habitats and associated fauna.

Organic carbon sequestration: The long-term storage of organic carbon in sediments, contributing to climate regulation by removing CO₂ from the water column.

Bioturbation: The reworking of sediments by living organisms, which influences nutrient cycling, sediment structure and organic matter distribution.

Recovery rate: The speed at which benthic communities and sediment properties return toward a reference or pre-disturbed state following cessation of trawling.

References

1. Assessing the impact of the global subsea telecommunications network on sedimentary organic carbon stocks. Nature Communications (2023).
2. Long-term carbon storage in shelf sea sediments reduced by intensive bottom trawling. Nature Geoscience (2024).
3. European coastal monitoring programmes may fail to identify impacts on benthic macrofauna caused by bottom trawling. Journal of Environmental Management (2023).
4. Response of benthic fauna to experimental bottom fishing: A global meta‐analysis. Fish and Fisheries (2018).
5. Trawl impacts on the relative status of biotic communities of seabed sedimentary habitats in 24 regions worldwide. Proceedings of the National Academy of Sciences of the United States of America (2022).