So let me see if I understand this new Siren mob correctly.

On the map I looked at I counted like 39-40 different places it can spawn spread out all over the ocean.

And only 1 spawns per server?

And it takes an hour to respawn?

And there is no way to tell if it's alive or dead on the server?

What a collossal waste of time, why would you do this? 

At least give us some indicator if the Siren is alive or dead on the server.

Not that hard, I've killed probably 150 so far.. lol

But yes, I agree with you, it can be a pain in the butt hopping to a server and not knowing if it's been killed recently.  Also, as others have mentioned, the music requirement is a pain in the butt as well as I prefer to play with music off.

Yeah, hunting down Hollow Maretta is a complete waste of time if she's in her cooldown period. Not hard, just tedious. Not even rare spawns for hunting are this awful.