These events can mean a vessel’s transponder is out of range or faulty. However, it can also mean that a vessel has turned off its transponder.
Events like this near no-take zones of marine protected areas can indicate illegal fishing.
Try it out: See the Suemanda fishing vessel's history of missing AIS data including just over 10 hours near the edge of a Marine National Park Zone (no-take) near Llewellyn Reef in the Great Barrier Reef.
You won't see the outline of the MPA no-take zone on your screen because a .geojson was added for temporary analysis.
For areas of interest where you might want permanent monitoring and even geofenced alerts, the team at Starboard can set these up in your Starboard account.