Question: If King Triton is the king of the sea, wouldn't he knew where Morgana was hiding? Do the humans know that Ariel and Melody are mermaids then if they do, do you think that those snotty kids would had told Melody?
Answer:King of the Sea does not mean psychic powers that allow him to be able to snuff out everyone's location. Only power he has is through the trident, which obviously cannot pinpoint location as he couldn't find Ariel when she was missing. It's likely the humans have no idea of the family's mermaid history, because yes, the snotty kids probably would have greatly teased Melody for it.
Answer: King of the Sea does not mean psychic powers that allow him to be able to snuff out everyone's location. Only power he has is through the trident, which obviously cannot pinpoint location as he couldn't find Ariel when she was missing. It's likely the humans have no idea of the family's mermaid history, because yes, the snotty kids probably would have greatly teased Melody for it.