1. Ancestors. If they had success living in a certain area, might be a good neighborhood to continue living in.
2. Food. Great way to grab a quick ocean meal when the food you enjoy eating lives nearby.
3. Predators. Think about the security and safety of not having to worry about being chased and hunted.
4. Climate. Consider how your body has adapted to a certain climate. For example, if your body has thick blubber to survive the cold you may not be comfortable in warmer areas.
5. Humans. They pollute coastal areas, decimate fish stocks, hunt marine mammals in certain areas and have a general careless attitude towards the health of your environment. Do your best to live in areas far away from them.