If the wandering island is...wandering...how the heck does it's ecosystem stay stable? I mean, certainly the island is going to be in different locations, and the flora and fauna would have to be quite adaptable to survive whatever the winds (both literally and figuratively) throw at it.
Also: How big is the Wandering Island, anyway? It'd have to be a pretty big turtle. What does Shen Zin Zu eat anyway if it's living (as evidenced by the blood)? The turtle must have a big appetite.
Meditate on this.