Canadian Hydrographic Service Ontario and Prairies Region CA372006 - SUPERIOR SHOAL See Notices to Mariners for subsequent corrections on this chart and Notices to Shipping in force for hazards or changes essential for the safety of navigation. © Fisheries and Oceans Canada 2022. Published by the Canadian Hydrographic Service. A licence is required from the Canadian Hydrographic Service (www.charts.gc.ca) to reproduce or distribute this work.