Evaluating connectivity of fisheries-derived marine debris from northwest African upwelling regions and entanglement exposure risk in the Canary Islands

Abstract

Marine debris derived from fisheries poses a significant threat to marine biodiversity in the Canary Islands, particularly within ecologically sensitive Special Areas of Conservation (SACs). This study integrates backward Lagrangian trajectory modeling with documented entanglement records to examine the connectivity between potential upstream debris source regions, regional transport pathways, and biological impacts affecting sea turtles and cetaceans in Tenerife, Gran Canaria, and Fuerteventura. A trajectory classification approach was implemented to quantify the proportion of simulated particles intersecting dynamically plausible upstream regions, including the northwest African coastal upwelling system and the Madeira sector. Results revealed seasonally variable connectivity between the archipelago and these regions, highlighting the combined effect of the Canary Current system and wind driven drift in facilitating cross-border debris transport. Entanglement was the most frequently documented impact on sea turtles, and fisheries-related plastic items constituted a dominant component of the debris pool. Although backward trajectory modeling identifies potential connectivity pathways rather than definitive source attribution, the integration of seasonal simulations and observational data supports a spatially explicit assessment of debris exposure risk within protected insular ecosystems. By linking upwelling-driven fisheries activity, fishing-derived ghost gear (ALDFG), regional circulation dynamics, and spatially resolved entanglement patterns within SACs, this study advances an integrated process-based framework applicable to other eastern boundary current systems.