the southeastern edge of the sepetiba bay is an area where the fresh water biomes extending from the slopes of the 'maciço da pedra branca' and the salt water habitats from the bay itself and the atlantic ocean beyond clash, creating a unique area of great biological diversity.

it is a region crisscrossed by several straits which divide it into several mangrove-covered islands, among which is suruquai island.

this island is located in the canal between the islands of capão, to the east, and bom jardim, to the west -  among the other named islands of this archipelago are also ilha nova, ilha do cavado, and ilha das baleias.