Here’s a link to a Transport Canada PDF outlining the procedure for if you find an abandoned vessel (wreck)
Any person taking possession of a wreck (i.e. salvaging) must report a found wreck. If you salvage a wreck, you are entitled to reasonable salvage costs and expenses for your efforts. The vessel owner is liable for these expenses. If the owner cannot be found, the salvage award may be the wreck, or all or part of the proceeds of its sale, but will not exceed the value of the wreck.
As a boat owner you are responsible for disposing of your boat.