Mapping the footprint of untracked small-scale fisheries using multicriteria spatial analysis and optical satellite imagery

The effective monitoring of small-scale fisheries footprint is critical for fisheries management and marine conservation. Yet, this remains challenging due to limited vessel tracking requirements for small boats under 12 m. This study presents the first attempt to combine Multi-Criteria Spatial Analysis (MCSA) and Sentinel-2 remote sensing approaches for mapping small-scale fisheries (SSF) footprint, using Sicily as a case study. The MCSA combined a habitat suitability index, informed by interviews with small-scale fishers across multiple Sicilian ports, with an activity index based on fleet characteristics and distance from the nearest ports. Sentinel-2 remote sensing data provided direct vessel detections using optical imagery processed by Global Fishing Watch, used for the first time in this study to map SSF vessels. A direct comparison between MCSA and Sentinel-2 datasets revealed a significant positive correlation (Spearman’s ρ: 0.43, p < 0.001). Both approaches consistently identified fishing hotspots and coldspots and showed stronger agreement for fishing hotspots (62% concordance) than for coldspots and neutral areas (34% and 47% concordance respectively). This outcome can be attributed to MCSA's more conservative approach, which identified twice as many coldspots as Sentinel-2. The robustness of our results underscores the necessity of combining the two approaches when estimating fisheries footprint, especially for SSF where tracking remains significantly constrained. By integrating MCSA with remote sensing, our approach enables large-scale SSF monitoring with considerably reduced logistical demands compared to extensive participatory mapping, offering a practical and replicable framework with critical implications for sustainable fisheries management and marine spatial planning globally.