In the Great Sea that covers most of the Southeastern Realm, there are pirates, all manner of ocean beasties, aquatic people, and the ocean itself. So, pirates and merchants of a wide variety of races who sail through oceans filled with merfolk and sahuagin and locathahs. The fish-people view aquatic monsters pretty much the same way land people view monsters; Sharks vs. Bulettes, Merrow vs. Ogres, etc.
All are at the mercy of the ocean’s whims, though, often encountered in the form of small elementals. As you get closer to the corner of the world, you see larger and more terrifying elementals until you reach the last Primal Wind Elemental, the Hurricane.