Really enjoyed this, a very polished experience!
(besides the buttons for the UI, but that doesn't matter that much)
Good use of the limitation and theme as well (a hexagonal grid with islands)
One thing was that the shell symbols on the water kind of blended in, but other than that I enjoyed it.
I think it took me about 10 attempts to finally complete it.
In a post-jam version, maybe you could add some more mechanics, like a danger that can never be next to another of the same type, which might add some more strategy.
Overall Great Work!