Because of the widespread press, fashion designers began calling the skimpy two piece female bathing suits, the bikini. Bikini conjures up tropical in a big way.
Of course, these registries are registries of convenience where the filing requirements (and other considerations like safety and environmental) are minimal.
The other interesting and ironic thing, is that because of the nuclear testing, Bikini is totally uninhabited by human beings. Yet ships are registered there.