If you go out on a Sunday and walk along the beaches, you'll see tons of families out swimming. Most people who live here are working during the day, so can't swim or hang out on the beaches and tourists are often out and about doing things and prefer to swim off the docks to avoid the sea grass. There are a few beaches where you can swim off the beach but the water is shallow in most places. There is no problem with barracudas or any other fish. I suspect someone was pulling your leg.