4th International Submarine Canyon Symposium (INCISE2018)
5-7 November 2018, Shenzhen, CHINA
This is the detail of ROV observations in intensively trawled submarine canyons of the Catalan margin (NW Mediterranean)
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Edit Time: 2018/9/21 2:12:48
Ruth Durán, Stefano Ambroso, Núria Callau, Claudio Lo Iacono, Fabio De Leo, Albert Palanques, Sarah Paradis, Marta Arjona-Camas and ABIDES Cruise Team
ROV observations in intensively trawled submarine canyons of the Catalan margin (NW Mediterranean)
In the framework of the ABIDES (Assessment of Bottom-trawling Impacts in DEep-sea Sediments) Project, a focused remotely operated vehicle (ROV) cruise was conducted in September 2017 to target heavily impacted fishing grounds on the submarine canyons incising the Catalan margin (NW Mediterranean).
Vessel monitoring system (VMS) data from March 2005 to September 2011 and Automated Information System (AIS) positioning information from April 2016 to April 2017 were analyzed to assess the spatial impact of trawling activities in this margin. Both sources of information indicate that trawling fleets on this region have been progressively specialized on a monospecific fishery targeting the blue and red deep-sea shrimp species (Aristeus antennatus), which is currently practiced at depths around 600-900 m. This bathymetric range has been experiencing a greater fishing effort than other continental slope regions, creating sharp boundaries between un-trawled and heavily trawled seafloor on numerous fishing grounds. ROV video transects were planned to cross this boundary, aiming to characterize the morphological and biological alteration induced by intensive trawling activities. Notorious morphological changes caused by the contact of the trawling gear over the seafloor were visualized and the seabed generally appeared as a ploughed field generated by the scarping of the otter boards during the successive fishing hauls of the trawling fleets. Push-cores were collected on un-trawled and trawled sites in order to characterize the changes on the surface sediment properties, whereas the analysis of the video footage has been used to evaluate the impact on the biodiversity of the benthic community.