An empty patch of map is not an empty waterway
A public ship tracker can only display reports its providers make available. When a vessel is absent, the map alone cannot tell you whether it is outside receiver coverage, missing from that feed or no longer represented by a recent report. Avoid jumping from no marker to no ship. The same caution applies around Canada's long coastline and inland waterways. A useful first question is whether the map has recent observations for the area at all, rather than whether one expected vessel can be found.
What Canada's official identification systems describe
The Canadian Coast Guard's maritime identification overview describes AIS reception through shore infrastructure, including the Great Lakes and St. Lawrence system, and distinguishes AIS from Long-Range Identification and Tracking. These are different systems serving official needs. A description of Coast Guard reception is not a promise that the same information appears on a commercial or educational website. PocketWorld does not claim access to Canada's official LRIT system or every report received by the Coast Guard.
Vessel Traffic Services is more than a public map
The Vessel Traffic Services overview explains how communications, AIS and other systems support monitoring and traffic organization. This operational service should not be confused with a website plotting an available feed. A public marker is not a traffic instruction, clearance or confirmation that an authority has contacted the vessel. Conversely, missing information in a web card does not establish what an operational traffic centre knows. Keep those boundaries explicit when sharing a screenshot or discussing an apparent gap.
Separate three kinds of missing information
A missing vessel, an old position and an incomplete identity card are different observations. For an old position, retain its actual timestamp instead of describing it as current. For a missing name, inspect the remaining identifier without guessing a ship's identity from its location. For absent regional coverage, report the limitation rather than substituting a count of zero. Official navigational warning resources are a separate source for published warnings; an AIS map's appearance is not an all-clear notice.
Make a useful comparison in PocketWorld
Open ship mode, select an available report and note the source, observation time and fields actually shown. Compare another observation only after checking those same details. Refreshing the page does not make an upstream report newer. If the expected vessel is unavailable, use official or provider resources appropriate to the question, and leave the result unresolved if the evidence is missing. This guide explains how to read coverage limitations; it does not offer a Coast Guard feed, emergency communications or navigation service. For marine conditions alongside traffic context, the separate Canadian weather guide points to forecast products rather than inferring weather from vessel movement.
Data sources
Official references are linked beside the explanations above. This educational guide does not report current marine conditions or provide navigation advice.