As with most things in life, this map is all about Risk vs Reward. Bonuses are labled on the map. There are 4 islands, Aul, Epoch, Isola and Iceburgh. Individually, each Island is worth -2 for no real reason. If you control one of the Islands along with one of the continents that border it, the Island adds +5 to the overall Continent bonus (Controling Avalisk is +3 but Avalisk with Iceburgh is worth +8). If anyone breaks your bonus anywhere, not only do you lose your continent bonus, but you also get the -2 for controling the Island.
Risk vs Reward
Some Light fog because people like that, I guess, but everything else is standard. You get 2 fortifies per turn.
Note: The Continent bonus for a Continent with an Island shows as +7 to make up for the -2 you will receive for controling Island to give a total of +5.