I find it difficult understanding what is land and what is water in this map. Even though it has text on the land regions, I think the water texture can confuse. In addition, you could reduce the amount of 'tearing' along the left edge of the map, where the land is, and this will help make the land easier to recognise at first glance.
It might also be because you've put it all on a black background - and your land is black. Usually what you see on the edges of a map, the brain takes it as 'water'. Yeah i'm sure this is it.