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

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.

Multi-sensor integration for an assessment of underwater radiated noise from common vessels in San Francisco Bay.

There is growing evidence that smaller vessels not required to broadcast data via the Automatic Identification System (AIS) contribute significant noise to urbanized coastal areas. The Marine Monitor (M2), a vessel tracking system that integrates AIS data with data collected via marine radar and high-definition camera, was employed to track all vessel types (regardless of AIS data availability) in a region of San Francisco Bay (SFB) where high-speed ferry, recreational, and commercial shipping traffic are common. Using a co-located hydrophone, source levels (SL) associated with 565 unique vessel passages were calculated and resultant cumulative daily sound exposure levels across the study area were modeled. Despite large ships primarily having the highest SLs, ferries and motorized recreational craft contributed noise to the largest area in two frequency bands of interest. The M2 provided data without the need for an on-site observer and enabled a systematic analysis of all relevant vessel types which showed that non-AIS vessels should not be excluded from consideration, especially in a highly urbanized estuary like SFB. This research provides an assessment of underwater radiated noise from all common vessel types in SFB suitable for informing habitat quality and threat evaluation for local cetacean species.