Bycatch rate

4. Discussion This study used a machine learning-based utility model to estimate policy–utility (ΔU) by integrating productivity (α), the immature fish proportion (β), and the bycatch rate (γ). The validation results showed strong stability (r = 0.901; RMSE = 0.22 on independent 2015–2016 data), demonstrating that the proposed model can reliably capture biological selectivity and the economic and ecological trade-offs that occur in the fishing industry.

4. Discussion The GFMI developed in this study revealed gear-specific characteristics and vulnerabilities across Korea’s coastal and offshore fisheries. In the coastal fisheries, the coastal gillnet fishery and coastal improved stow net fishery showed relatively high overall GFMI scores, largely reflecting penalties on reproductive capacity, bycatch, and gear loss. Consistent with this, Gilman et al.

From 2017 through 2020, cetacean bycatch mortality in Spanish fleets was estimated using only data from the European Union (EU) Data Collection Framework (DCF) data, which was designed for scientific sampling of commercial fish catches, especially discards. Although this programme has included the collection of data on the incidental bycatch of vulnerable species since 2017 (EU 2016), its estimates have been questioned because they may underestimate cetacean bycatches (ICES 2019).