The island has an area of 774,2 ha and is quite steep with limestone cliffs covered with dense jungle right down to the water's edge and few beaches. The wall drops to 180 m and currents can be strong with upwelling, downcurrent and reversing directions.
The most distinctive feature is the huge brackish water lake in the middle of the island, in the local dialect Kakaban means "hug" as the island hugs the lake from the surrounding seawater.
In the middle of this island is a mangrove fringed lake, slightly above sea level, where millions of non-stinging jellyfish live making it interesting for diving. The jellyfish consist of four different species which have lost their natural defense system because of the lack of major predators in the lake.
The lake has warm brackish water and the bottom is covered with marine green algae. There are other animals living here, some sea cucumbers, gobies, anemones, tunicates, crustaceans, nudibranchs, orange purple clams and yellow clams on the branches and snakes.
The lake is at most 17 meters deep with poor visibility and is 10 minutes walk from the beach. Kakaban was probably uplifted during the Holocene and sea water was trapped turning the area and formed a landlocked marine lake. The water is now a mixture of salt water and sweet water from the rain.
This dive takes place in a freshwater lake that is filled with millions of non stinging jellyfish. The reason divers come here is because it provides a once in a lifetime opportunity for the diver to be totally surrounded by jellyfish - without the fear of being stung! The whole lake has yet to be explored as divers have remained in the shallows nearer to the shores. This is due to the eerie feeling that many divers get when being totally surrounded by so many jellyfish, and also because the life around the edges is also interesting. The roots of the mango trees that enter the water are covered in soft sponges while the anemones that sit in the grassy areas devour any of the hapless jellyfish who sink to the bottom within their reach.
The diver is well advised to dive within their limits here and only the most experienced should consider venturing into the deeper waters. This is not a dive that suits everyone's taste, but it is a unique experience for all who take the plunge.