Evidence of large increases in sedimentation rates due to fish trawling in submarine canyons of the Gulf of Palermo (SW Mediterranean)

11 pages, 5 figures, 2 tables

Bottom trawling in submarine canyons can affect their natural sedimentation rates, but studies addressing this issue are still scarce. In the Gulf of Palermo (SW Mediterranean), bottom trawling occurs on the slope around Oreto, Arenella and Eleuterio canyons. Analyses of excess 210Pb concentrations and grain size fractions in sediment cores from their canyon axes revealed that sedimentation rates and silt contents increased in all canyons in the 1980s, due to the expansion of more powerful trawlers (>500 HP) to deeper fishing grounds. In Eleuterio and Arenella canyons, sedimentation rates increased by an order of magnitude (0.1-1.4 cm·yr-1), whereas they increased less (0.1-0.7 cm·yr-1) in Oreto Canyon, since the enhanced trawling-derived sediment fluxes into this canyon are affected by sediment resuspension from trawling along its axis. Considering the global expansion of bottom trawling, we anticipate similar alterations in other trawled canyons, with ecological consequences that should be addressed by management strategies

The results presented in this study were obtained within the Exploring SiciLian CAnyoN Dynamics (ISLAND) project, supported by the European Commission, Seventh Framework Programme (EUROFLEETS2 (grant no. 312762)). The analyses were funded by the “Assessment of Bottom-trawling Impacts in Deep-sea Sediments” (ABIDES) Spanish Research Project (CTM2015-65142-R). Additional funds were provided by the Generalitat de Catalunya (2017 SGR-863 and SGR-1588), by the Australian Research Council LIEF Project (LE170100219) and by the Spanish Research Project ABRIC (RTI2018-096434-B-I00). This work is contributing to the ICTA's “Unit of Excellence” Maria de Maetzu (CEX2019-000940-M), and ICM's “Center of Excellence” Severo Ochoa (CEX2019-000928-S). The IAEA is grateful for the support provided to its Environment Laboratories by the Government of the Principality of Monaco. CLI was supported by the H2020 MSC Action HABISS (GA 890815)

Peer reviewed