The vast majority of internet traffic originating from Canada doesn't actually go through these lines. Do a MTR/traceroute to anywhere and unless you're on specific commercial networks, all of your traffic will be going through a US Internet Exchange at some point because it's way cheaper for your local greedy telecom.
Here are their ASNs:
- Greenland Connect: Tusass A/S (AS8818)
- St. Pierre and Miquelon Cable: SPM Telecom (AS3695)
- EXA Express: EXA Infrastructure (AS30740)
- Topaz: Google (AS15169)
Two are terminal links to connect isolated regions, the other two are commercial links not used by home internet users.