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Chronic and intensive bottom trawling impairs deep-sea biodiversity and ecosystem functioning
Antonio Pusceddu1, Silvia Bianchelli2, Jacobo Martín3
1Department of Life and Environmental Sciences, Polytechnic University of Marche, 60131 Ancona, Italy; a.pusceddu@univpm.it.
Summary
Bottom trawling severely degrades deep-sea ecosystems by depleting organic matter and reducing biodiversity. This fishing practice threatens the health of the global deep seafloor.
Area of Science:
- Marine Biology
- Deep-Sea Ecology
- Fisheries Science
Background:
- Bottom trawling is a historically significant fishing practice, expanding to greater depths.
- Concerns regarding the sustainability of trawling have increased since the early 20th century.
- This method impacts marine ecosystems, affecting seafood stocks, benthic organisms, and sediment dynamics.
Purpose of the Study:
- To assess the impacts of chronic bottom trawling on deep-sea sediments.
- To quantify changes in organic matter, carbon turnover, and meiofauna in trawled versus untrawled areas.
- To evaluate the global threat of deep-sea trawling to seafloor ecosystems.
Main Methods:
- Comparison of chronically trawled and untrawled sediment sites.
- Analysis of organic matter content and organic carbon turnover rates.
- Assessment of meiofauna abundance, biodiversity, and nematode species richness.
Main Results:
- Trawled sediments showed significant decreases in organic matter (up to 52%) and slower carbon turnover (37%).
- Meiofauna abundance dropped by 80%, biodiversity by 50%, and nematode species richness by 25% in trawled areas.
- Daily organic carbon removal by trawling estimated at 60-100% of input flux in the study region.
Conclusions:
- Bottom trawling causes degradation of deep-sea sedimentary habitats and reduces infaunal populations.
- The practice represents a major global threat to deep seafloor ecosystems.
- Urgent consideration of deep-sea trawling's sustainability is needed.