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Poso and Malili Lake System, Paradise of Endemic Fishes

There might be less information available regarding Duck-billed Buntingi and Caridina dennerli, as each of the freshwater species only lives in certain areas. The Duck-billed Buntingi only inhabits Lake Poso, Central Sulawesi; while the Caridina dennerli can only be found in Lake Matano, South Sulawesi. There is no other place in the world that harbours these species.

Both places are paradise of endemic freshwater biota in the world. In Lake Poso alone, for example, there are 16 endemic freshwater species of fishes, shrimps, and molluscs. Aside from the Duck-billed Buntingi Adrianichthys kruyti, there are also Poso Bungu Weberogobius amadi and Popta’s Buntingi Xenopoecilus poptae. Unfortunately, those three unique fish species are currently Critically Endangered. That is to say, if their habitat in Lake Poso is damaged, they will be extinct.

The same goes for Lake Matano that is a part of Malili Lake System. The Malili Lake System consists of five interconnected lakes. Its three main lakes, Matano, Mahalona, and Towuti, are even directly connected.

Those lakes are located on different levels of height, resulting in the water from Matano to flow to Mahalona and from Mahalona to Towuti. The water from Towuti then flows to Larona and Malili River that end in Bone Bay.

Uniquely, although the lakes are interconnected, the faunas in each of those lakes are different. “Many of them are even endemic to a single location,” said Jihad, Burung Indonesia’s Bird Conservation Officer. The Ricefish Oryzias matanensis, for example, is endemic to Lake Matano. Its family, O. profundicola only exists in Lake Towuti; while O. hadiatyae is indigenuos to Lake Masapi—one of the small lakes in Malili Lake System.

Due to its high level of endemicity, various kinds of new species continue to be found by scientists in the Malili Lake System. In 2006, Kristina Zitzler from Museum of Natural History, Berlin, Germany, discovered a freshwater shrimp species, Caridina spongicola, in Lake Towuti. It is later known that there are still more endemic freshwater shrimp species in the Malili Lake System that have not been named and scientifically studied. “And yet, some of the Malili’s endemic shrimps are already known worldwide as ornamental shrimps coveted by freshwater aquarium enthusiasts. If they are not sustainably managed, those endemic species will be threatened as a result,” said Adi Widyanto, Regional Implementation Team Leader of Critical Ecosystem Partnership Fund (CEPF) from Burung Indonesia.

In addition to being hunted for hobby, the biodiversity in Malili Lake System is also facing another form of threats. One of them is the introduction of freshwater fishes, such as Nile tilapia, flowerhorn, and plecostomus that turned out to be predators or competitors, threatening the local species.

Comprehensive ecosystem and species conservation efforts are needed to save important areas such as Poso and Malili, therefore, CEPF included Lake Poso and Malili Lake System in its prioritised funding areas for biodiversity conservation.

In November 2015, Burung Indonesia as Regional Implementation Team of CEPF welcomed proposals submission for small grant projects by local and national civil society organisations for conservation in these areas. The grant was expected to motivate the communities to protect threatened biodiversity in Wallacea.