Bottom fishing beyond trawling. Spatio-temporal trends of mobile and static bottom fisheries on benthic habitats

The effective implementation of the Marine Strategy Framework Directive (MSFD) and formulation of spatial management policies rely heavily on a good understanding of the extent, distribution and intensity of human pressures and their overlap with benthic habitats. However, little research has quantified the pressure and impact on the seabed of bottom contact gears other than trawling. This study analyzes the spatio-temporal trends of fishing pressure of bottom-contact gear, including mobile and static gears, and asseses its relative importance within each benthic habitat. To achieve this, a set of pressure indicators was calculated using vessel monitoring system information from the Bay of Biscay for 2009-2020. Nested General Linear Models were conducted to assess the temporal fluctuation of fishing activities. While trawlers exhibited wider and higher levels of fishing intensity over sedimentary habitats, set gillnet and set longliners were distributed among more sensitive habitats, such as biogenic reef habitats. Additionally, there was a significant decrease in fishing effort in recent years along Offshore circalittoral habitats, particularly with respect bottom trawling, in contrast to increasing fishing intensity in deeper areas. These results emphasize that from a conservation perspective and MSFD implementation, there is a need to quantitatively analyze the fishing footprint of all fishing gears, including static gears in the regional assessments, and the necessity to progress in adapting impact indicators to these fishing activities. The findings are discussed based on the potential impacts of policies such as the MSFD and can assist managers in developing spatial protection measures.

Automated summary

This study analyzes the spatio-temporal trends of fishing pressure of bottom-contact gear and assesses its relative importance within each benthic habitat. The findings are important for the conservation of marine biodiversity and the development of spatial protection measures.