Obvious things like food, water, clothes, rain gear and tents.
A sleeping bag rated to at least 0 deg. F even though it never got below 35 deg. F while we were there. And quality does matter.
A GOOD machete for all that brush.
A flash light.
Bug spray and maybe some fly-paper for all the flys that buzz you when sitting still.
An insect head net can come in handy. And Duct Tape to tape around your cuffs and ankles to keep the bugs out.
A day pack for hiking into the interior for the day.
Rubber boots (in case you arrive by boat during low tide).
Water proof tarps and a roll of twine.
Good quality rain gear, like Cabella's Gore-Tex Silent Weave coats and pants. It didn't rain much, but the gear was worthe it's weight in gold for keeping the morning dew off your clothes.