Freshwater fauna of Sulawesi is at risk of extinction
We admire them in our aquariums. We protect them in their homes. Aquarists, scientists, zoo keepers, conservationists… we all work together.
"Dream island" of Sulawesi
Sulawesi, governed by Indonesia, is one of the Greater Sunda Islands and is located east of Borneo. It is famous for its unique freshwater life – species of fish, shrimps, crabs, snails and other invertebrates and plants not found anywhere else on this planet.
Laboratory of evolution
Most of the diversity of the aquatic fauna is found in the lakes of central Sulawesi: Lake Poso and the Malili lake system, which is made up of three large lakes (Matano, Towuti, Mahalona), two smaller lakes and interconnected waterways.
These lakes are of tectonic origin and they are estimated to be over 1 million years old. They have a significant depth (Matano is 590 m deep!), a unique chemical composition, but above all, they are home to hundreds of species ranging from diatoms to fish that do not live anywhere else on earth. 99% of the species living in Malili Lakes are endemic to them! That is why it is so painful to see how this underwater paradise is being destroyed and many species are disappearing.
Did you know that the beautiful and popular shrimp Caridina dennerli is facing extinction?
This tiny red crustacean is only known from a single Sulawesi lake Matano. Along with the spread of invasive fish, shrimp numbers are rapidly declining. Despite an intensive search in 2017 and 2018, not a single specimen was found! The IUCN Red List category for this species has been changed accordingly to "Critically Endangered (Possibly Extinct in the Wild)", see here.
But wait! In 2019, researchers with the help of local shrimp hunters found these iconic shrimps hiding under a thick layer of rocks in two places in Matano. Shrimps are not found on the places where they used to be, they stay deep under the rocks (at least 30 cm) hiding from the invasive predators. They are not safe there. The bottom is covered with a thick layer of mud and algae, which is not a normal condition, and the oxygen under the rocks can be easily depleted.
Can we find them on the next try?
… and it is not the only one…
Other shrimps are also affected by the invasive predatory fish. Nearly all 15 shrimp species from the Malili Lakes are classified as Critically Endangered with a single exception ("only" Endangered).