This novella was inspired by the song The Deep (by clipping.), which I haven’t listened to yet. The premise is that the pregnant and going-into-labor slaves who were thrown overboard midocean (true) gave birth to mer-people (probably not true) who built a whole civilization and society around a historian who remembers everything so that the rest of them don’t have to. The story is mostly about the current historian who is having difficulties with this burden, but it also goes back into the memories. It’s very good.