Dwindling deep-water fish stocks in the Azores: The first quantitative assessment

Anthropogenic impacts on marine ecosystems are increasing, especially in the deep-sea. Deep-water fishing effort has increased rapidly in the last four decades. However, the economics and sustainability of deep-water fisheries remain debated. This study applied the Stochastic Surplus Production Model in Continuous Time (SPiCT) model to provide the first quantitative assessment of four data-limited deep-water/demersal fish stocks using the Azores as a case study. The application of SPiCT followed good practice and benchmark assessment guidelines and converged for all four assessed stocks. The results showed that blackspot seabream, blackbelly rosefish, and red porgy are classified as overfished, while forkbeard is classified as a recovering stock. These findings underscore the vulnerability of these deep-water stocks to overfishing and advocate for reductions in current catches based on the recommended harvest control rules. Additionally, the study demonstrates that the SPiCT model serves as a valuable tool for stock assessment in data-limited deep-water/demersal fisheries and can enhance their category to data-moderated stocks.