Data-limited vulnerability assessment of demersal fisheries in French overseas territories

Small-scale demersal fisheries in tropical territories support local economies and food security but are difficult to assess because of multispecies catches, diverse fishing practices, and limited biological and fisheries data. As a result, most stocks fall within data-limited categories for which conventional analytical assessments are not feasible. This study applied a productivity–Susceptibility Analysis (PSA) to evaluate the relative vulnerability of 172 demersal stocks (234 species) exploited by artisanal fisheries in five tropical territories: French Guiana, French Antilles, Mayotte, Réunion Island, and French Polynesia. To improve the interpretability of the results, vulnerability thresholds were calibrated using categories from the IUCN Red List as an independent reference for biological risk. The analysis revealed distinct regional differences in the vulnerability of the stocks. Mayotte exhibited the highest vulnerability, driven by both low productivity and high susceptibility, which is potentially linked to limited management measures regulating catch and harvest size. In French Guiana, vulnerability was also high but was mainly associated with low productivity, whereas susceptibility remained close to the regional average. Conversely, the French Antilles showed the lowest susceptibility scores, contributing to an overall lower vulnerability. These results highlight strong regional and taxonomic differences in vulnerability and reveal substantial knowledge gaps in life history and fisheries data. This study demonstrates that context-specific calibration of PSA thresholds can improve vulnerability screening and help prioritise research and precautionary management in tropical, data-limited fisheries.