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Subansiri River tributary, Arunachal Pradesh, India
India, Arunachal Pradesh, Changlang District
The floodplains and forested foot-hills of northeastern India, especially around Dibrugarh, Tinsukia, and Namdapha, experience monsoon-fed seasonal pools, slow-flowing tributaries, and forest swamp zones. These are shaded, leaf-litter rich, with driftwood, clayish or sandy beds, and minimal aquatic vegetation. Water is often slightly acidic and low-flow.
- Submitted by
- Shivansh Rajpoot
- Approved by
- Hans-Georg Evers & Friedrich Bitter
- GPS
- 27.5035915, 96.3764572
- Geographical region
- Southern Asia
- Drainage Basin
- Brahmaputra
- River catchment
- Water body type
- River
- Water body name
- Noa Dihing
- Water body part
- Flood plain
- Water body course
- Middle course
- Water body: tributary of
- River
- Tributary name
- Brahmaputra
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Water Chemistry
Water information
- Water type
- fresh-water
- Water color
- Clear water
- Water transparency
- Medium
- Concentration of sediments
- Low
- Water temperature
- 24 °C
- Water flow/curent
- Slow
Chemical parameters
- pH
- 6.0
- Conductivity
- 100
- GH
- 125 mg/l
- dGH
- KH
- 36 mg/l
- dKH
- Dissolved Oxygen
- 95 %
Substrate in nature
- Sand
- Beige
- Pebble/Gravel
- None
- Stone
- Grey
- Stone form
- Roundish
- Silt/Mud
- None
- Leaves
- Few
- Driftwood
- Few
- Submerged terrestrial vegetation
- Yes
Aquatic Biotope
- Date of collecting
- 23/04/2025
- Collecting area
- Flooded area
- Water depth
- 2,0m
- Air temperature
- 26 °C
- Sunlight
- Partial shade
Environment
- Environment
- Untouched
- Surrounding area
The biotope is based in the subtropical lowland forests of Arunachal Pradesh, India, near Namdapha National Park. This region, located in the Eastern Himalayas, is among the world’s biodiversity hotspots.
The area experiences high rainfall from May to October and maintains mild to warm temperatures year-round. Dense forest canopies shade narrow streams that flow through leaf-littered forest floors, supporting unique fish species including Channa bleheri. The region is largely untouched and home to elephants, hornbills, red pandas, and a vast diversity of insects and amphibia.
- Underwater landscape
The watercourse is a slow-moving forest stream with a soft sandy-clay substrate, scattered with large amounts of leaf litter, driftwood, and some rounded stones. The water is lightly stained with tannins due to decaying plant matter.
Aquatic vegetation is sparse; instead, algae, periphyton, and fine detritus dominate. Floating debris and submerged roots offer natural hiding spots.
Visibility varies seasonally, with dry months offering clearer conditions. This environment suits Channa bleheri, which uses wood and leaves for cover and surface hunting.
- Threats to ecology
Though some areas are protected, deforestation, mining, and agriculture are gradually encroaching upon Northeastern India’s natural waterways.
Road construction and illegal logging pose serious threats to aquatic biodiversity.
The introduction of exotic species and pesticide runoff further disrupt local ecosystems.
Conservation of pristine biotopes like this is vital not only for endemic fish such as Channa bleheri but also for countless lesser-known freshwater species dependent on stable forest stream environments.
Riparian zone
- Trees near the aquatic habitat
-
Few - Shorea robusta (Dipterocarpaceae)
- Trees near the aquatic habitat
-
Few - Ficus religiosa (Moraceae)
Bibliography
-
Smithsonian Contributions to Zoology - Channa bleheri
by Sven O. Kullander
-
Zoological Survey of India - Snakehead Fishes of India
by Ralf Britz
ISBN 9788181712703
-
Morphological notes on Channa bleheri
by Ralf Britz
Comment by the expert
Hans-Georg Evers: Well researched, understanding the biotope.
Friedrich Bitter: There is a discrepancy between the named biotope and the presented species or its name!
