Just got back from a trip down in that area to take my nieces and nephews out fishing. Find a mangrove point like at the mouth of a creek with a good current flow. Sometimes they will be in the current more times they will be in the eddy waiting to ambush their next meal. Use small wire hooks almost what you would use for pan fish. Fresh dead shrimp works just as good as live shrimp. To keep the mangrove snapper interested every so often throw a couple of dead shrimp or other cut up bait over as chum. Good luck!