Lake Towuti

Lake Towuti is the largest lake on the island of Sulawesi by surface area, spreading across 561.1 square kilometres of a tectonic basin in East Luwu Regency, South Sulawesi. It sits at 293 metres above sea level, with an average depth of 120 metres and a maximum of 203 metres, and it holds an estimated 67.33 cubic kilometres of water, smaller by depth than its neighbour Matano, to which it is connected by the short Larona River, but larger in surface area than any other lake in the province. Towuti belongs to the same ancient Malili lake system as Matano and shares its reputation for unusual, highly localised wildlife. Telmatherinid sailfin silversides, small and often brightly finned fish, have diversified here into several forms found nowhere else, alongside endemic gobies and halfbeaks. The lake's most scientifically distinctive resident may be Caridina spongicola, a freshwater shrimp that lives exclusively on freshwater sponges in the lake, one of only two commensal freshwater shrimp species known anywhere in the world. Endemic Tylomelania snails and Parathelphusid crabs round out a food web that has evolved in relative isolation for hundreds of thousands of years. The lake's shoreline is dominated by the mining town of Sorowako, which sits on the strip of land separating Towuti from Lake Matano and serves as the practical base for visiting either lake. From viewpoints in the hills above Sorowako, both lakes are visible at once, laid out in the forested basin like two halves of a single landscape. Because Towuti and Matano sit in a remote part of interior South Sulawesi, most visitors reach the area by a domestic flight to a regional airstrip followed by a road transfer, and facilities remain oriented toward research and mining-industry travel rather than mass tourism, which keeps both lakes quiet even by Indonesian standards.