The sushi bar makes more money than its one appearance in the movie suggests.
The one time it appears is when it's clearly stated there're no sharks nearby. Normally the occasional shark must eat enough there to keep business going at least until Oscar defeats Don Lino. The movie is set in the same universe as Waterworld
It's not a copy of New York, it's ACTUAL New York after the oceans rose, covering the world.- But how's that explains the fact that characters in this movie are anthropomorphic animals, while humans live on surface?