The park is located on either side of the mouth of the Sanaga River along the shores of the Bight of Biafra opposite the island of Bioko.

[1] Lake Tissongo, a lagoon connected to the south bank of the Sanaga River by a 5 kilometres (3.1 mi) tidal channel, is included in the reserve.

[2] The mangroves form a buffer against coastal erosion, and are a refuge for 80% of the local marine and aquatic species for at least part of their lifecycle.

They are threatened by logging for construction timber and for firewood used in fish smoking, as well as by urban infrastructure development.

[10] The endangered red-eared nose-spotted guenon was reported in the Lombé part of the reserve in densities of 2–3 groups per square kilometers, but populations had dropped elsewhere due to hunting.