Mooring buoys are either public, or private and they are usually marked. In British Columbia
the public buoys are clearly marked in areas such as Montague Harbour. Fees
apply for their use, and instructions advise you to pay a fee at the Marine
in the area. Private buoys vary as to markings, but should not be used because their owner may return when you may be off your boat and trouble may result.
State, private mooring buoys are subject to a permit
process controlled by the Department of Natural Resources. Although, some may have been placed without permits, it is best only use public buoys to avoid any conflicts. I do not know the rules or practices for placing private buoys in B C.
I did find some information here
that may lead you to more information on public buoys available for your use in B C..