Sires world stuff
subject to change i really don't know what's going on here
angery sounds
In ye olde days, humans hunted and killed both sirens and merpeople because sirens hunted people, and humans didn't differentiate between them. This caused the remaining merpeople to avoid people and dislike sirens. However, since sirens prefer to eat people, most didn't avoid them, which led to them having significantly fewer numbers than merpeople. Some sirens who continued to kill people developed methods to hide their presense, such as killing stealthily or killing witnesses.
Today, it is generally accepted that both merpeople and sirens exist. However, people who don't regularly interact with large bodies of water may not know about them. Some beaches may still have minor, old siren warning signs, and some old people may have tales about them. Sirens and merpeople don't have a myth-like status, but they are very rare.