Map showing frequency of red hair across Europe. Five color-coded ranges: red (over 10%) concentrated in Ireland and Scotland, orange (5-9%) in parts of UK and northern Europe, brown (2-4%) in Scandinavia and Germany, darker brown (1-2%) in central Europe, and darkest brown (under 1%) in southern Europe. Shows clear north-south gradient with highest concentrations in Celtic regions.
The light blue splotches are lakes.
That makes more sense. But not as much sense as making them the same color as the ocean.