Indus River Delta - A Global Ecoregion
Home to the endangered Indus River dolphin
Snapshot: Ecoregion 156
Size:
40,000 sq. km (16,000 sq. miles)
Habitat type:
Large River Deltas
Western part of the Indian subcontinent: Pakistan
Conservation Status:
Critical/Endangered
Quiz Time!
Is the Indus River dolphin blind?
Answer:
After thousands of years of living in cloudy water, the Indus River dolphin has nearly lost its eyesight because it no longer needs it. Instead it has evolved a special ability called "echolocation" for hunting and navigation. The dolphin swims on its side and detects prey and other objects through sound waves.
About the Area
Originating at Lake Ngangla Ringco high on the Tibetan Plateau, the Indus flows more than 3,000 kilometers, creating a wide delta of swamps, streams, and extensive mangroves just before pouring into the Arabian Sea.
For a long distance, the river is a wide channel of cloudy water, providing mineral-rich soil and water to its floodplains.
It is home to one of the few species of freshwater dolphin worldwide, the Indus River dolphin (Platanista minor) and numerous species of distinctive fishes, many of which live in or migrate through the waters of the Indus River Delta.Important food species like large freshwater shrimp (Macrobrachium spp.) are part of the abundant aquatic life of the delta.
Local Species
In addition to Indus River dolphin, the river is home to a number of endemic fishes, including Indus baril (Barilius modestus), Indus garua (Clupisoma naziri) and Rita catfish (Rita rita).
Several snakehead fishes also live here, including Giant snakehead (Channa marulius), which can grow to be 6 feet (2 m) long and eats fish, frogs, snakes, insects, and earthworms.
There are even reports that it will occasionally eat a water bird! The Hilsa shad (Tenualosa ilisha) swims up from the Arabian Sea to spawn in freshwater. This fast swimmer has been clocked at 71 km per day.
Threats
Dams on the river reduce flows in lower portions of the system and limit the transport of fertile sediments downstream into the delta. They also pose a serious threat to the survival of the Indus River dolphin, as the remaining dolphins become isolated into smaller groups.
Water extraction for irrigation, runoff of chemicals into the rivers, and introduced species also threaten the freshwater species of the delta.
Resources
• NationalGeographic.com
