A preliminary risk analysis of vessel traffic on selected cetacean populations within the Pelagos sanctuary

Abstract

The Pelagos Sanctuary, a transboundary Marine Protected Area (MPA) in the northwestern Mediterranean Sea, represents a critical habitat for several cetacean species, including fin whales (Balaenoptera physalus), sperm whales (Physeter macrocephalus), and striped dolphins (Stenella coeruleoalba). However, increasing maritime activity within the region poses significant conservation challenges, primarily due to vessel traffic, ship strikes, underwater noise pollution, and habitat fragmentation. This study conducts a preliminary risk analysis of vessel traffic impacts on selected cetacean populations within the Sanctuary, utilising Automatic Identification System (AIS) data in conjunction with the ACCOBAMS Aerial Survey Initiative (ASI) cetacean sighting records. The analysis focuses on the spatial and temporal distribution of maritime routes, assessing their overlap with critical feeding, breeding, and migration areas. Findings indicate that high-density vessel traffic zones coincide with key cetacean habitats, exacerbating the risk of direct collisions, particularly for large whales that exhibit predictable movement patterns. Additionally, the persistent presence of high-speed ferries and cargo ships contributes to chronic acoustic pollution, interfering with essential cetacean behaviours such as communication, foraging, and navigation. The study also highlights the limitations of current management frameworks, revealing gaps in regulatory enforcement across the tri-national governance of the Sanctuary. Despite existing mitigation measures, such as voluntary speed reductions and designated shipping corridors, compliance remains inconsistent, undermining conservation efforts. To address these challenges, this research proposes a suite of policy recommendations, including the implementation of dynamic spatial management strategies, stricter enforcement of vessel speed restrictions, and the incorporation of real-time cetacean monitoring technologies. Furthermore, it suggests integrating Maritime Spatial Planning (MSP) principles into the Sanctuary’s governance framework, which could enhance cross-border coordination and ensure the protection of critical habitats. Ultimately, this study reiterates the urgent need for an interdisciplinary and adaptive conservation approach that balances economic interests with marine protection, ensuring the long-term sustainability of the Pelagos Sanctuary’s biodiversity.