The Silver Seas
The Silver Seas is the name for the southern ocean waters between the mainland and the Shiral islands. It is populated densely by nix, who thrive in the warm, shallow waters. Nixie communities along the coasts interact regularly with tellurans, and have become known for their advances in medicine, fueled by the many materials available to them from the reefs, as well as the relative protection they had from the cataclysm which protected them from a complete loss of history and techniques, unlike the vast majority of tellurans. The narrower area of easterly sea, between the mainland and the eastern end of the Shiral islands, is more often referred to as the Silver Sound, but there is no distinct seperation between the two. The sound is an area of common ship traffic, both along the coasts and out to the islands. Ships from the sea rarely venture all the way out to the islands, instead transporting goods and passengers only across the sea to other points on the mainland.
Naufrage Archipelago
The Naufrage Archipelago is aptly named for its dangerous waters. The combination of widespread equatorial upwelling driving currents away from the center of the sea, the input of cold water from the west around the continent, and the rapid warming of this water, particularly in the center of the sea, all drive rapid, swirling currents. Eddies are common, and shoals and seamounts that may not be visible until too late pose a great risk to seafarers. Combine this with choppier waters compared to the smoother waters of the sea- protected from much of the open ocean's wave action by the islands- and few sailors are willing or able to brave the waters, as they have sunk many a ship.
Unknown Depths
The Unknown Depths, also called the Chimerae's depths or just the Depths, is the name given to the trench system just oceanward of the Naufrage Archipelago and the Shiral islands. It's formed by the subduction of the Austric tectonic plate beneath the Occident and Eastern ones. The Depths often refers to specifically the triple point between all three, where the ocean floor falls dramatically. Here is where the Chimerae reside, though that is only myth to tellurans and even other merfolk. All that is known of the Chimerae is what merfolk occasionally find drifting up from the Depths- nothing more than bloated bodies and the occasional piece of something distinctly humanoid-made. Nevertheless, these mysteries spawn numerous legends that are carried by merfolk and sailors alike.