During previous phases of EMODnet biology, two R packages were created to aid fisheries management decisions. The Btrait and Bfiat R-packages (Soetaert and Beauchard, 2023, 2024) provide a deterministic modelling framework that describes depletion of benthic species density or biomass during a trawling disturbance, and its subsequent recovery in between fishing events. The average biomass or level of ecosystem functioning under trawling disturbance, estimated as a fraction of its pre-disturbance state then provides a quantitative expression of the trawling impact.
Here the Bfiat methodology is applied to benthic data from EMODnet Biology (Beauchard and Soetaert, 2026), from the Dutch part of the North Sea, for the year 2009. Using the Bfiat model, we quantify how bottom fishing interacts with species life-history traits to shape benthic state in terms of reduction in benthic biomass and the potential of the benthic fauna to mix and bio-irrigate the sediment (the so-called bioturbation and bio-irrigation potential of sediments). The two latter traits are important as they affect sediment geochemistry and global biogeochemical cycles.
Understanding the impact of bottom trawling gear on benthic life is a necessary step towards a correct assessment of fisheries impact.
Dr. Karline Soetaert, NIOZ
Figure 1. Fishing intensity expressed as annual swept area ratio (units /yr) for the year 2009 in the Dutch part of the Northsea, B. The fraction of the total benthic biomass lost by fishing (in 2009). C. The fraction of bioturbation (mixing) potential lost by fishing (in 2009), D. The fraction of bio-irrigation potential lost by fishing.
References:
Beauchard, O, and Soetaert, K, 2026. Bottom fishing assessment tool: An R package to model the effects of bottom trawling on the marine benthos. Ecological Applications(36) 5, e70282. URL https://doi.org/10.1002/eap.70282
Sciberras, M., J. G. Hiddink, S. Jennings, C. L. Szostek, K. M. Hughes, B. Kneafsey, L. J. Clarke, et al. 2018. Response of Benthic Fauna to Experimental Bottom Fishing: A Global Meta-Analysis. Fish and Fisheries 19: 698–715.
Soetaert, K and O Beauchard, 2023. R-package Btrait: Working with Biological density, taxonomy, and trait composition data. Data product created under the European Marine Observation Data Network (EMODnet) Biology Phase IV. <https://github.com/EMODnet/Btrait>
Soetaert, K and O Beauchard, 2024. R-package Bfiat: Tools for estimating the impact of bottom disturbance on sediment ecosystems. Data product created under the European Marine Observation Data Network (EMODnet) Biology Phase V, under the NECCTON project (New Copernicus Capability for Trophic Ocean Networks), and under the OceanICU (understanding Ocean Carbon) project.