To view different types of fishing vessel data, on the top of the left sidebar, we have the Activity section.
- The ‘apparent fishing effort’ includes AIS and VMS data.
- AIS data can be filtered by flag and gear type.
- VMS data can be filtered by source, flag and, in some cases, by gear type, fleet and origin.
- The data can also be filtered by a subset of vessels by creating a vessel group.
- The ‘vessel presence’ layer analyzes AIS data collected from vessels that our research has identified. The activity layer displays a heatmap of vessel presence. The presence is determined by taking one position per hour per vessel from the positions transmitted by the vessel’s AIS.
- The ‘vessel presence’ layer can be filtered by fishing and carrier, among other vessel types.
To view different types of detections data, use the Detections section.
- The night light detections layer, known as visible infrared imaging radiometer suite or VIIRS, shows vessels at sea that satellites have detected by the light they emit at night. Though not exclusively associated with fishing vessels, this activity layer is likely to show vessels associated with activities like squid fishing, which use bright lights and fish at night. Global Fishing Watch has used a sophisticated matching system to match night light vessel detections with AIS information to identify vessels emitting light, and those that aren’t transmitting their identity. This matching is done using a probabilistic model that determines AIS-message/VIIRS-detection pairs based on all available AIS records right before and right after the time the VIIRS image was taken, as well as the probability of pairing a specific AIS message to any of the vessels appearing on that image.
- The radar detections layer, known as synthetic aperture radar or SAR, shows at-sea vessels in any weather conditions. SAR can show vessel detections that cannot be picked up by other cooperative tracking systems (e.g. AIS or VMS). SAR is a satellite-based sensor that shoots microwaves to the Earth surface and measures reflections (or “backscatter”) to provide information on the features on the water.