Summary
This study measured deep-sea elasmobranch (DSE) bycatch on a commercial crustacean bottom trawler off of southern Portugal between June 2020 and May 2022, and collected data from Global Fishing Watch to estimate the bycatch of deep-sea sharks since 2017, which is the year that trawling below 800m was banned in the region. DSE represents a high proportion of total catch biomass, especially at depths below 800m; despite EU regulations restricting fishing to only occur above 800m, bottom trawlers were regularly observed operating below that depth. Analyses suggest that substantial numbers of DSE have been caught in the five years following the prohibition on bottom trawling below 800m in the Northeast Atlantic.