Coastal waters of the Kapas River in the dry season of Harapan Rainforest in Jambi, Sumatra

31st place in Biotope Aquarium Design Contest 2018

russia Argentina. Walter Vázquez

Volume: 125 L
Dimensions: 50x50x50 cm
List of fishes: Puntigrus tetrazona
List of plants: N/A
Description of decorations: For the hardscape of the aquarium use sands of various sizes, small rocks to resemble the soil of the area represented, branches, leaves, and branches of palm fruit, one of the plants surrounding the waters of the forest area.
Description of equipment: The tank background its a black vinyl. The lighting of the aquarium is based on 6500K and 2700K LED lamps.It is filtered by an Atman 3335 canister with biological and mechanical material. The water heating is given by an Eheim Thermocontrol of 100w.
Water parameters: The water temperature ranges between 27° and 28°C. The pH is 6.0–6.5 and hardness is 9° dH.


Description of the area surrounding the biotope: The Harapan rainforest covers 98,554 ha of dry lowland forests and comprises two old timber concessions of approximately the same size. The whole site has been subject to a certain degree of logging, which results in three broad forest habitats: “secondary high forest”, “secondary secondary forest” and “low secondary forest”. 40% of the site is ‘high secondary forest’, and 25% is ‘low secondary forest’. The remaining 10% includes scrub and open field. Harapan Rainforest is home to an impressive variety of mammals, including the Sumatran tiger, the Asian elephant, the Malay bear, the Mitred langur, the Asian tapir, Siamang, the clouded leopard, the Agile gibbon, the slow loris and the Dhole (Asian wild dog), all of which are currently in danger of extinction. Harapan Rainforest is also home to nearly 300 species of lowland birds, including eight globally threatened species and 69 near-threatened species. The diversity of fish in the Harapan forest consists of 123 species, 25 families and 52 genera. Cyprinidae has many species (59 species of fish). Despite the previous disturbance of the habitat, there is still a remarkable abundance of species. It is believed that the diversity potential of freshwater fish in this area is very high due to its different habitat. The amount of new fish species found in the Harapan forest can be much higher than that of the Batanghari river basin. Hutan Harapan rainforest is rich in freshwater habitat. Based on the results of the study and with the support of secondary data through questionnaires and interviews with residents of the border, there are four watersheds in the Harapan forest, which include: the Meranti watershed, the Kapas watershed, the Lalan watershed and the Kandang watershed.
In Hutan Harapan you can find about 37 bodies of water composed of 7 main rivers, 9 lakes and major marshes, 10 small tributaries and 11 lakes and shallow marshes. In the rainy season, the number of aquatic habitats in the Harapan Rainforest may increase due to the fact that the catchment area and the basin are flooded, until now some of these aquatic habitats have not yet been named. The main rivers of the Harapan rainforest have the character of a river flooded with several small tributaries and short cuts of rivers and some shallow lakes along its current. When it rains, the water quickly overflows and floods a few hundred meters from the river’s edge, but in the coming days, when it does not rain, the water recedes quickly. At low tide, the water that is in a low place will be trapped, so that a shallow swamp and a small lake will form as the main character of the Banjir River. In the dry season the river becomes very shallow, the tributaries are dry, so they can be crossed on foot and some marshes and water lakes are separated from the main river. Flood zones and wetlands are characterized by the annual variability of flood zones along major flooded rivers.
The main rivers found in the Harapan Rainforest include: Kapas River, Meranti River, Sungai Lalan, Sungai Kandang, Sungai Bungin, Sungai Jerat, Sungai Telang and Mase Rusa River. The Kapas River is the largest river in the Harapan Raiforest and most of them have tributaries, lakes and flooded marshes followed by the Meranti River, however, these two rivers are in the middle. Creek contained in the Kapas River include: Bato River, Nangoi River, Nawai River,Timbun Tulang River, Badak River, Tanam Tubo River, Cawang River, Bujang Palembang River and Sungai Ibul. The shallow marshes and lakes are found along the Kapas river flow include: Rawa Bato, Bayumi short cut, Nigepak Siam lake, Bedegum lake, Muara Perkat swamp, Chili lake, Seprena lake, Begarih lake, direct access Ci Imah, Lake Palau has no mouth and Cincang Kayu Lake. Jambi is one of the provinces of Sumatra with great potential for diversity of endemic freshwater fish. Jambi has the second highest endimicity, 20.7% (12 types) after western Sumatra which is 24.1% (14 species), while the province of Lampung has an endemicity of freshwater fish lower 5.2% (3 types). The opportunity to find new records of species in Jambi, especially in freshwater habitats, is still very large. The diversity of freshwater fish in Jambi is going to increase because there are many areas that have a lot of potential. The habitat of freshwater fish, especially those found in the forest, has not been inventoried, for example in the waters of the Harapan Rainforest.
Sungai Kapas is the main river in the Harapan rainforest, located in the position of the coordinates S 103º 17′ 17.463″ and E 02º 14′ 54.382″ with a height of 54 m. above sea level. Upstream is Sarolangun (Jambi) and the districts downstream of Musi Regency and Banyu Asin (South Sumatra). Sungai Kapas has many tributaries, lakes and alluvial plains. The vegetation around the river includes palm trees, makaranga, jambuan, European guava, kelat and medang meranti. In the rainy season, the depth of the Kapas River is ± 15 m and the width of the stream is up to 250 m. Along the banks of the submerged river the water acts as a floodplain area, similarly, it will be distributed to the flooded area and the amount of fish will be trapped more than what is usually left, fish also breed in the rainy season between October and February and begins intensely from November to January when floods begin to decrease and temperatures begin to rise, so that the amount of fish in these months is higher. On the contrary, during the dry season, the main surface of the Kapas river recedes with a maximum depth of 2 m at the bottom of the river and a width of the streams of 12m while the width of the river reaches 50 m.

Description of the underwater landscape of the biotope: In this river the substrate of white sand base with stones and leaves. The width of the river when in normal conditions is 30-50 meters with a depth of 1.5 – 5 m. During large floods, the width of the river reaches between 100-300 m. and a depth of 6-15 m. During the flow of the dry season the river narrows like a ditch and many large trunks cross.

Description of the parameters of the habitat: The water of the river is aquamarine color. The physico – chemical parameters of the water in the dry season of the Kapas river show a temperature of 28.5 ° C, an oxygenation of 5.1 mg / L, and a pH of 5.9.

List of fishes and invertebrates occurring in the nature biotope: There are 7 fish families whose members can be found throughout the year including Cyprinidae, Bagridae, Osphronemidae, Pristolepidae, Siluridae, and in addition to the types found only once throughout the year divided into 8 families, including Bagridae, Belontidae, Cyprinidae, Eleotridiade, Pangasidae, Siluridae, Synbaranchidae and Tetradontodae. Puntigrus tetrazona, can be found throughout the year, together with Parachella hypothalamus, Puntius lateristriga and Hamid macrolepidota. In the same way for the species that only are in certain times they are the members of the families Cyprinidae like; Balantiocheilos melanopterus, Osteochilus melanopleura and Macrochytys macrochirus.

List of plants found in the nature biotope: N/A

Threats to the ecology: The most widespread invasion occurred in 2007 covering an area of 6,300 hectares of oil palm plantation. The rate of decline in large forests has many consequences because more species that depend on forests face the risk of extinction. Most of these species survive in an increasingly narrow area without any protection effort.

Sources of information: – Diversity and distribution of fish in the waters of Harapan rainforest in Jambi – Tedjo Sukmono

Comments of the members of the jury of Biotope Aquarium Design Contest 2018