According to the SPM ferry schedule for February 2020, there are some Sunday departures from Saint Pierre (France) to Fortune (Canada):
But according to the Fortune CBSA Office hours, the point of entry will be closed to passengers at this point:
Travellers
Office Hours (Seasonal)
08:45 - 17:00
Monday to Friday (except holidays)
October 1 to March 3108:45 - 17:00
7 days a week (including holidays)
April 1 to September 30
On a February Sunday, when I arrive in Fortune, the office will be closed. Even in summer I would arrive just at closing time. There are also some summer departures which arrive when the office is closed (such as June Wednesdays on 19:30).
How can I enter Canada if I arrive from this ferry when the border office is closed?