GNF - Mahakam Lakes and Wetlands

Mahakam Lakes and Wetlands – Borneo, Indonesia

Background Mahakam Lakes and Wetlands

Situated on the worlds second largest island, Kalimantan, formerly known as Borneo, inherits the unique Mahakam Area. The Mahakam Area is part of East Kalimantan, where wilderness and jungle prevail. The Middle Mahakam Area (MMA) comprises the lakes Danau Jempang, Danau Melingtang and Danau Semayang and is located in a geological depression covering an area of about 4,000 square kilometers. Depending on seasonal variations, the lakes size ranges between 0 and 600 square kilometers. The annual fluctuation can reach more than six meters.

The MMA is situated between 180 km and 375 km from the mouth of Mahakam river and includes three major and several minor lakes, peat and freshwater swamps and major tributaries. It is one of Kalimantan''s largest wetland areas. These lakes and swamps are very important fish-spawning grounds and replenish the main river seasonally. Therefore, the MMA is an area of intensive fishing activity with an annual catch of 25,000 to 35,000 metric tons since 1970.

The area has a high biodiversity potential in terms of breeding and migratory bird species and also hosts the symbol species of East Kalimantan, the critically endangered Irrawaddy Dolphin (Orcaella brevirostris), who lives in fresh, brackish and salt water.


Habitat protection requires the establishment of community supported and law enforced zones of critical wetlands, lakes and river habitat in the MMA. In this respect, a more holistic approach is needed to match the overlapping interests in the usage of the area by the different stakeholders such as fishermen, farmers, government, mining companies, etc..


Protection of the Irrawaddy Dolphin population is already pursued since the year 2000 with the help of several supporters and is mostly focused on increasing awareness of schoolchildren and fishermen. One task is the direct patrols in major dolphin areas to relocate dangerously placed nets and check for entangled dolphins.

Other species inhabiting the area are endangered mammals such as Proboscis Monkeys (Nasalis larvatus), wild Banteng (Bos javanicus) and Crocodiles (Crocodylus siamensis and Tomistoma schlegeli).

 Fisher settlement
 Plantation of oil palms on Borneo
 Fire clearing on Borneo
 Intact nature

Threats Mahakam Lakes and Wetlands

Several serious threats have been identified for this unique area

  • Species extinction and habitat loss due to land conversion in plantations.
  • Unpredictable changes in the hydrology because of dredging activities, dam building, river control, mining, logging and plantation activities.
  • Pollution by pesticides (more than 100,000 ha of oil palm plantations are being set up) and mercury (caused by gold mining activities).
  • Forest fires and illegal logging of riparian forest causing habitat loss and increases sedimentation.
  • Over-fishing and unsustainable fishing techniques such as electro-fishing and intentional fish poisoning with pesticides.
  • Noise and fuel pollution from boat traffic disturbing breeding bird populations and Irrawaddy Dolphins.
  • Hunting of protected and endangered species such as herons, storks, hornbills, crocodiles and turtles.
  • Direct mortality of Irrawaddy Dolphins through gillnets. The present mortality rate is five dolphins per year on average.
  • Increased sedimentation in the lakes causing the dolphins'' migratory pathway to coincide with a narrow, dredged pathway for high speed boat traffic.

Required activities

  • Conducting conservation activities based on biological and social-economical research in East Kalimantan.
  • Protecting endangered, aquatic related species and their freshwater and marine habitats and ecosystems.
  • Conserving natural resources with importance to humankind.
  • Promoting sustainable use of natural resources of the aquatic environment and provide alternative living resources in case of unsustainable use of natural resources.
  • Establishing a community supported and law-enforced zonation design for critical wetlands, lakes and river habitat with regards to extractive, restricted and prohibitive use of natural resources and bird, fish spawning and freshwater dolphin protected areas.

More information about Mahakam Lakes and Wetlands

 Landschaft mit Monokulturen
 Nasenaffen sind auf natürliche Lebensräume angewiesen.
 Natürlicher Baumbestand am Ufer

Project measures Mahakam Lakes and Wetlands

Yayasan Konservasi (YK) RASI (Conservation Foundation for Rare Aquatic Species of Indonesia) is a non-profit, non-governmental organisation situated in East Kalimantan. The main focus of RASI is to fight against the loss of aquatic species and deteriorating habitats in the area.

RASI consists of 10 members among which there are two consultants of foreign NGOs. Specific field projects are conducted by free-lance staff, who is recruited from the students'' organisation of the Forestry Faculty of the local Mulawarman University and trained by permanent staff members.


A project on sustainable fisheries was launched in spring 2009 by RASI and the GNF and funded by the Federal Agency for Nature Conservation (BfN) and the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU) as part of the special stamp programme.

The GNF and its local partner organisation RASI are supported in dolphin conservation in the Mahakam region by the Ursula Merz Foundation.



Partner Organisation Mahakam Lakes and Wetlands


YK-RASI (Rare Aquatic Species of Indonesia)

Mr. Budiono

Jl. Kedondong Dalam VI RT 5 No.2

Samarinda 75123

Kaltim (East Kalimantan), Indonesia




Dr. Danielle Kreb, Scientific Program Advisor

Yayasan Konservasi RASI

P.O. Box 1105

Komp: Pandan Harum Indah (Erlisa), Blok D, No. 87

Samarinda, Kalimantan Timur, Indonesia

Phone / Fax: + 62 - 541 - 20 64 06

 Logo RASI