Original sentence: This and the contested sovereignty claims over the waters may complicate future shipping through the region: the Canadian government considers the Northwestern Passages part of the Canadian Internal Waters, but various countries maintain they are international waters beyond Canadian jurisdiction
Edited sentence: This and the contested sovereignty claims over the waters may complicate future shipping through the region: the Canadian government considers the Northwestern Passages part of the Canadian Internal Waters, but even though clearly in Canadian waters various countries maintain they are international waters beyond Canadian jurisdiction