The impact of anchoring on seafloor integrity : an integrated assessment within a major bunkering area of the Maltese Islands

Abstract

International shipping is a fundamental component of the global economy. As the industry expands, the demand for high-capacity vessels increases, raising concerns about their impact on the marine environment. While awaiting access to port facilities, vessels often anchor to save fuel and prevent drifting, but this practice is a significant cause of mechanical disturbance to the seafloor and benthic habitats. Identifying and quantifying anchoring pressure is essential for better managing and mitigating the damage to the seafloor. The Automatic Identification System (AIS) can be utilized to assess anchoring pressure by transmitting vessel information (e.g., position, type and size) to other vessels and coastal stations. This research evaluates anchoring pressure in a strategically located bunkering area around the Maltese Islands using AIS data collected from an antenna at the University of Malta. An arbitrary index was developed to determine anchoring pressure, and the AIS data was used to create GIS maps showing the location and size of vessels within the bunkering area, as well as plots depicting anchoring pressure by vessel type, seasonality, and density. This study serves as a blueprint for future assessments of anchoring pressures from various maritime activities in other areas around the Maltese Islands and provides a decision support tool for national policy-making related to Descriptor 6 (Seafloor Integrity) of the Marine Strategy Framework Directive (MSFD), the Maritime Spatial Planning Directive (MSPD), and the management plan for Sites of Community Interest (SCI) and Marine Protected Areas (MPAs).