I received a question yesterday from one Nicholas Lionrider of Spiral Live fame:
Again, I'm not going to really say much here of my own accord, but let me link you to a couple of places and let you connect the dots. One, you should pay attention to what's being said about the worlds before it links to the three you mention (From the Pirate101 website):
"Travel with your Pirate crew through unknown Skyways and experience familiar worlds like you've never seen before!"
Two things: unknown skyways and familiar worlds.
Next, let me link you over to the Wired Geek Dad article where Matt Forbeck talks a bit about the worlds of Pirate101:
"While both games are set in the Spiral, they only share one world to start with: the Asian-flavored realm of Mooshu. Among the new realms in Pirate101, you’ll find Skull Island, Cool Ranch, and Valencia."
I'm pretty sure that answers your question. ;)