If you see water extending beyond the shore that doesn't match the ocean background, you are looking at parcels of land that are below sea-level and covered in shallow water. While these shallows can be deep enough to allow for boat travel, they are in most cases very shallow and present both hazards for nautical navigation and opportunities for building, if you possess the technology to build piers and quays. The To'resk, in particular, are quite adept at building with these technologies and many coastal To'resk settlements are built "out over the shallow water" supported on wood pilings driven into the ground beneath the shallow water.

Hope that helps! :)