You would think that once all the technologies had been researched, they would figure out fishing poles, nets, crab/lobster traps and so forth. Well, maybe not lobsters (I think they are only found in cold water).
If you were stranded on an island, at some point, wouldn't you build a boat? Maybe it isn't the first thing you need to do. Maybe you aren't even building it for escape, maybe you would use it for fishing, courting the pretty ladies, or disposing of lazy villagers who dislike work by giving them a pair of cement overshoes. But my villagers have never shown an interest in boat building whatsoever.