Lyric discussion by myimaginaryband 

Cover art for Sea People lyrics by Emilíana Torrini

I think this song is kind of about being in love with a mermaid (sea people). But at the same time it's a metaphor for love in reality. Life, when it's hard, can be a lot like drowning. But when you look into the eyes of your love, you can breathe in water. However, when they say goodbye... your lungs ache filled with water.

That's just my take on it.