Coastal radar as a tool for continuous and fine-scale monitoring of vessel activities of interest in the vicinity of marine protected areas

Abstract

Marine protected areas (MPAs) are widely utilized for conservation of the world’s marine resources. Yet, compliance with MPA regulations remains difficult to measure because of limits to human resources and a lack of affordable technologies to automate monitoring over time. The Marine Monitor, an autonomous vessel monitoring, recording, and reporting system leveraging commercial off-the-shelf X-band marine radar to detect and track vessels, was used to monitor five nearshore California MPAs simultaneously and continuously to identify and compare site-specific use patterns over one year. Vessel tracks were classified into two movement patterns to capture likely fishing activity, “focal” or “linear”, that corresponded with local targeted species. Some illegal fishing potentially occurred at all sites (7–17% of tracks depending on site) most frequently on weekends and at mid-day, but the majority of activity occurred just outside the MPAs and in the near vicinity suggesting both a high level of compliance with regulations and awareness of MPA boundaries. Time spent engaged in potential fishing activity compared to track counts suggests that unique vessels may spend more time fishing inside area boundaries at some sites than others. The spatial distribution of activity shows distinct concentrations near MPA boundaries at all sites which strongly suggests vessels purposefully target the narrow area at the MPA boundary or “fish the line”, a potential acknowledgement of successful spillover. This activity increased significantly during some local fishing seasons. Concentration of activity at MPA boundaries highlights the importance of continuous monitoring at a high spatial and temporal resolution. Reporting of vessel behavior at a fine-scale using radar can help resource managers target enforcement efforts and understand human use patterns near coastal MPAs.

Movement, ranging patterns and habitat use of Indo‐Pacific humpback dolphins (Sousa chinensis) in the Langkawi Archipelago and adjacent Perlis‐Kedah coastal waters, Malaysia

“…Straits of Malacca, one of the busiest shipping routes) to minimize collisions and underwater noise disturbance. Enforce these measures effectively by tracking and monitoring shipping activities using an Automated Identification System and consider utilizing monitoring systems such as the Marine Monitor (M2) to monitor nearshore marine habitats (e.g. Cope et al, 2022). Exclusion of coastal development and zoning Exclude large‐scale coastal development in dolphin habitats, specifically the population core areas in Kilim, eastern Langkawi, Kuala Sanglang and Kuala Kedah. Adopt proper zoning plans and stringent environmental mitigation standards in areas of planned coastal development where dolphin habitats are present. Bycatch mitigation Implement the use of bycatch mitigation devices, such as acoustic pingers or acrylic glass spheres (Barlow & Cameron, 2003; Kratzer et al, 2020), in high‐risk bycatch fishing gears (e.g.…”

“…• Enforce these measures effectively by tracking and monitoring shipping activities using an Automated Identification System and consider utilizing monitoring systems such as the Marine Monitor (M2) to monitor nearshore marine habitats (e.g. Cope et al, 2022).…”

Building a Practical Multi-Sensor Platform for Monitoring Vessel Activity near Marine Protected Areas: Case Studies from Urban and Remote Locations

“…The confidence score is stored as a track statistic and can be used to classify and isolate only those radar tracks predicted to be true vessels. Tracks are typically classified with greater than 90% accuracy [76,77].…”

Understanding vessel noise across a network of marine protected areas

“…Vessel monitoring systems (VMS), which include a transmitter-receiver system, provide information on a particular pre-defined sector, typically fishing vessels targeting federally managed fish stocks (Birchenough et al, 2021 ). Reporting of vessel behavior at a fine scale using radar can help resource managers target enforcement efforts and understand human use patterns within coastal marine protected areas (Cope et al, 2020 , 2022 ). Satellite imagery has been used to detect vessels (Müller et al, 2013 ; Paolo et al, 2024 ), expanding monitoring further offshore.…”