Nature Conservation Unit. An open coastal lagoon near Robertsport to the west of Monrovia, the largest such inlet on the Liberian coast, surrounded by forested hillsides (including one of the rarest tropical rainforests in the region) and fed by a number of creeks and rivers; these latter drain a series of swamps above the lagoon, the lower ones of which are tidal and support mangroves. Other mangrove swamps occur behind the dune ridge on the west side of the lake mouth and at other creek mouths. A series of small lakes with swampy margins occurs on the sandy forested spit that separates the lake from the sea. Some 38 communities, totaling about 7000 people, depend upon Piso for transportation, commercial and non-commercial fishing, and sand for construction, and farm-to-market infrastructure was well-developed prior to the civil crisis of the past decade. The site is important both as a nursery and spawning ground for fish and sea turtles and as feeding and roosting places for large numbers of shore and sea birds. Mammals such as antelopes, duikers, monkeys, bushbucks, and a few crocodiles are also found in the area.
