ABIDES-ROV Cruise, RV Sarmiento de Gamboa

Abstract

The ABIDES (Assessment of Bottom-trawling Impacts in DEep-sea Sediments) project focuses on the study of contemporary sedimentary processes associated to the impact of bottom trawling activities on the deep seafloor. The disturbance of deep-sea environments caused by this fishing practice is considered to be notably higher than all other anthropogenic pressures combined, given its intensity, recurrence and wide geographical distribution. Although the impacts of trawling on coastal and shelf environments have been investigated in the past from the sedimentary point of view, up to date, very few studies have addressed the role of this fishing practice on slope environments, where background energy levels controlling natural sedimentary processes are generally low and where the associated benthic ecosystems are less resilient and more vulnerable. Therefore, the main goal of the ABIDES project is to improve our knowledge of the contemporary sediment erosion, transport and accumulation processes driven by this anthropogenic activity, with the aim to assess the magnitude of the associated impacts in continental slope environments and to provide support for mitigation efforts towards the development of sustainable fisheries. During the ABIDES-ROV cruise we have conducted a morphological and seabed habitat characterization of the continental slope regions that have (and have not) been intensively trawled during decades, both at small- and large-scale with the aim to evaluate the “seafloor integrity”. The main study area has been the NW Mediterranean continental margin, where a bottom trawling fishery has been operating for decades and a good knowledge of the current bottom-trawling footprint exists. ROV footage has been used to determine the small-scale morphological changes and the impact caused by trawling gear on the seafloor habitats through direct visual observations; and detailed multibeam bathymetric mapping will be used to identify large-scale morphological changes caused by persistent trawling activities over major fishing grounds of the study area