You will always find debris in any water even if no hurricane blew in. There are people called "litter bugs" and they don't give a crap where they dispose their waste. I have stepped on beer bottles , cans, boards, forks, etc. while swimming (and not only in SXM). If you are being cautious, wear water shoes. No one can predict what you may step on so be safe. While boating in Barnegat Bay years after Sandy, we hit a refridgerator in the water and also patio furniture.