so i posted this in the Force and destiny beginner box forum but i haven't seen any new posts in a while. my question is this: In the beginning of the adventure the players have to fight hunters, What is their species?

I don't think it was ever mentioned. When I read the encounter, I imagined them as being native humans. But it sounds like it's up to you.

I went with the picture of the hunters in the book which portrays them as humans.

When I ran this, I kept their species vague until much later, when I was running a portion of the Lure of the Lost follow-up adventure. At that point, i revealed they were part of a small community of Zabraks, mostly just to put the rest of the players off their game as they'd assumed humans as most people are wont to do.