Maybe have a rare chance of getting bumped by a whale, knocking loose coconuts and damaging foundation. Have a rare occurrence happing after killing the second shark of an albatross swooping in and stealing fish/shark meat that doesn't have a floor above it.
Ooh, you could also add a rare chance of a huge swordfish catching your fishing rod and dragging you some distance. That could also change up your location a bit, maybe giving you an alternate type of shark or something.
Yeah, I know. All I can come up with is rare occurrences. I just think the surprises would shake things up in a fun way.