Over a three-day workshop in February 2026, partners from across CIBBRiNA and sister project REDUCE convened in Lisbon and online for a workshop on how fishing effort data can best be plugged into modelling approaches to produce more precise and accurate estimates for total bycatch of Endangered, Threatened, and Protected (ETP) species.
Currently, fishing effort is typically calculated using Days at Sea (DaS) for ETP bycatch assessment. When combined with data obtained from bycatch monitoring (such as observer programmes and self-reporting by fishers), it is possible to estimate how much bycatch is happening in total. However, while DaS is used as a standardised fishing effort unit across fleets, gear types, and regions, this metric has limitations when it comes to estimating bycatch. In particular, it does not fully capture variation in the deployment and intensity of fishing gear. Alternative effort metrics, including soak time, the number of nets/hooks, and fishing gear dimensions, have been recommended as more suitable effort metrics for bycatch estimation.
Workshop participants sought to address these challenges by evaluating CIBBRiNA’s eight case studies, covering a range of gear types including gillnets, longlines, and trawls. They concluded that, although effort data availability varies across regions and fisheries, structured approaches combining DaS with more detailed and high-resolution metrics (such as net length and soak time) provide a robust foundation for better bycatch assessments. An extra advantage of these approaches is the potential to analyse fishing activity at a higher spatial resolution than the currently-used ICES areas, which will allow for bycatch assessment at finer geographic scales.
By improving the understanding of how a ‘day at sea’ translates into fishing effort across different regions and gear types, researchers can identify when current models could be improved to better reflect actual fishing activity and associated bycatch. This harmonised approach will be essential for achieving CIBBRiNA’s goal of minimising ETP bycatch and supporting more sustainable fisheries across Europe.
Read the full report here.