Lakes Ankerika, Antsamaka, Soamalipo and Befotaka form the wetlands of the Manambolomaty complex, 35 km south-west of Antsalova, and are surrounded by the Tsimembo Forest. Lake Ankerika is located in the commune of Trangahy, and the three others in the commune of Masoarivo. Lakes Soamalipo and Befotaka are linked. The lakes lie on alluvial soils and most are freshwater and permanent, with a depth of 3–6 m depending on the season. Lake Antsamaka is brackish and 3 m deep during the rainy season, but may completely dry up at the end of the dry season. Aquatic vegetation at this lake includes water-lilies Nymphaea and rushes Juncus. In the southern part of the lakes, an area of 98 ha has been converted to seasonal marshes and rice-fields. Tsimembo Forest is bounded by the Manambolomaty river in the south and by the Beboka river in the north, and consists of dense, dry deciduous forest. Dominant canopy trees include Dalbergia, Stereospermum, Givotia, Xylia, Cordyla, Hildegardia, Delonix and Diospyros. The mid-stratum is dominated by species of Rubiaceae, Euphorbiaceae and Leguminosae. On patches of much sandier soil (old sand-dunes), the forest canopy is lower and there are fewer emergents. The part of the Tsimembo Forest that surrounds Lake Antsamaka is called Ankotrofotsy Forest.
See Box and Tables 2 and 3 for key species. Ninety-three species are known from the site, of which 29 are endemic to Madagascar. The site holds 10 pairs of Haliaeetus vociferoides, representing c.10% of the world population. There is an islet which is a roosting and nesting site for herons (Ardeidae) such as Ardea humbloti, and for Anas bernieri.
The lakes, together with a strip of 1 km around them, form a Ramsar Site, pursuant to Law 98-003 of 19 February 1998. Lakes Soamalipo, Ankerika and Befotaka are mainly threatened by increasing sedimentation rates (following increased soil erosion) and by the conversion of marshes to rice-fields. Other threats include the burning of pastures, deforestation, and the illegal cutting of trees for firewood to dry fish, which has caused the number of nesting Ardea humbloti to decrease substantially in recent times.