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Poso and Malili Complex, the Endemic Fish Paradise

The Duck-billed Buntingi and Sulawesi Cardinal Shrimp are not widely known, for both freshwater animals are living in Poso Lake in Central Sulawesi and Matano Lake in South Sulawesi, respectively. They cannot be found anywhere else in the world.

Lake Matano which holds great potential for aquatic animals, including the Sulawesi Cardinal Shrimp. (Photo: Tri Susanti/Burung Indonesia)

Both places are paradise for the world's endemic freshwater biotas. In Lake Poso, for example, there are 16 endemic species of fish, shrimp and freshwater mollusks. The Duck-billed Buntingi (Adrianichthys kruyti) is inhabiting the lake, along with the Poso Bungu (Weberogobius amadi) and Popta's Buntingi (Xenopoecilus poptae). Unfortunately, these three unique fish species are currently in Critical status, which means that if their habitat in Lake Poso is damaged, the three of them will become globally extinct.

Lake Matano is also part of the Malili Lake Complex. The complex itself consists of five interconnected lakes where the three main lakes, Matano, Mahalona and Towuti, are directly connected.

Located at different elevations, water from Matano flows to Mahalona then to Towuti. Water from Towuti then travels through the Larona and Malili Rivers, and reaches Bone Bay.

The Sulawesi Cardinal Shrimp (Caridina dennerli), one of the shrimp endemics to Matano (Photo: Tri Susanti/Burung Indonesia)

Uniquely, although the lakes are connected to each other, the animals that live in each lake are different. "In fact, many of them are endemic species for one location," said Jihad, Bird Conservation Officer of Burung Indonesia. Take the Matano Ricefish (Oryzias matanensis), which is endemic to Matano Lake. Its relatives, O. profundicola, lives only in Towuti Lake while O. hadiatyae is endemic to Masapi Lake—one of small lakes in Malili Lakes.

With the high level of endemicity in the Malili Complex, scientists continue to discover new species. In 2006, Kristina Zitzler of the Museum of Natural History, Berlin, Germany, discovered the freshwater shrimp Caridina spongicola in Lake Towuti. It was later discovered that there are still a number of endemic freshwater shrimp species in the Malili Complex that have not been named and studied scientifically. "In fact, several types of Malili endemic shrimp have crossed the world as ornamental shrimp that are hunted by freshwater aquarium fans. As a result, these endemic species are threatened with extinction if not managed sustainably,” said Adi Widyanto, Regional Implementation Team Leader of the Wallacea Critical Ecosystem Partnership Fund (CEPF) from Burung Indonesia.

The biodiversity in Malili Complex is facing a number of threats, aside from hunting for recreation. The program for releasing introduced freshwater fish such as tilapia, louhan and Suckermouth catfish has turned out to be a predator or competitor that threatens the preservation of the Malili local biological species.

Introduced fish in Lake Matano which threatens the preservation of local biodiversity. (Photo: Tri Susanti/Burung Indonesia)

Therefore, the Critical Ecosystems Partnership Fund has designated Lake Poso and the Malili Lake Complex among the priority areas of funding for biodiversity conservation, considering a comprehensive effort to conserve species and ecosystems is needed to save important areas such as Poso and Malili.

In November 2015, Burung Indonesia, as the regional implementation team for CEPF, opened a small grant proposal from local and national civil society organizations for conservation efforts in this area. This assistance is expected to be able to motivate the community to preserve diversity with threats of extinction in Wallacea region.