Fine-scale mapping of ocean user groups to support species and habitat spatial management

Context: Maritime vessel activity is pervasive in the world's oceans causing detrimental impacts on marine ecosystems. The management and monitoring of vessel activity has historically been focused on industrial vessels, however, and is often conducted only at large spatial scales and coarse resolutions. A more holistic approach is needed to understand where and when different maritime fleets are impacting the marine environment, particularly within protected areas. Aims and methods: Here we explore fine-scale (50 m2) spatiotemporal patterns of multi-fleet vessel activity using Satellite Automatic Identification System (S-AIS) data over a two-year period (2018 - 2019) within a network of marine protected areas (MPAs) and their conservation features, using the biologically distinct oceanic archipelago of the Isles of Scilly (UK) as a case study. Key results: Vessel activity was widespread, affecting over 87 % of the study area. However, high-intensity activity was concentrated along key transit and shipping routes. Recreational and passenger vessels posed the greatest pressure within MPAs, particularly on conservation-critical features like European shag habitats and seagrass beds. Seagrass beds faced additional pressures from anchoring and mooring, with impact pressure up to four times higher than in other habitats. Conclusions: These findings reveal the complexity of mapping vessel impacts within MPAs and underscore the value of high-resolution analyses. Further research is needed to understand the in-situ effects on marine communities, particularly in high-pressure areas. Ignoring these cumulative impacts in monitoring strategies may compromise the effectiveness of MPAs in achieving their conservation goals.