I don't believe that is an island, I think it wraps around the southern peak. I don't actually care if there is seafood on the otherside of that peak, can scout that later, but the dependent on that, a city where teh scout is, or the tile north of the sheep could be a later Moai city (I think north of sheep is better because it can reach size 9 and 19 base hpt with just a lighthouse and the improved sheep using workshops).
I went through these screenshots of demos, and for some reason on T8 crop yield increased for the leader to 6. So either someone settled a 3 food capital or they improved a 4 yield seafood, and I don't know why they would have done that: It would be better to go wandering. Turn 9 shows the leader at 7 food, so someone did hook a 5 yield seafood tile.