Question

Why are some species native to the Ganges River, such as the Ganges river dolphin, becoming endangered?

The river contains many invasive species.


The river is heavily polluted.


The river is suffering from saltwater intrusion.


The river frequently floods.

Answer 1

Short answer: mainly because of heavy pollution, habitat loss/flow changes and fishing-related impacts. Of your options:

- The river contains many invasive species — partly true. Invasives can disrupt food webs and compete with native fish, which reduces prey for dolphins and stresses other natives, so this is a contributing factor (but not the primary one).
- The river is heavily polluted — yes. Industrial and agricultural effluent, untreated sewage and chemical contaminants degrade water quality, reduce prey, cause disease and mortality, and drive long‑term population declines.
- The river is suffering from saltwater intrusion — sometimes true in the delta. Reduced freshwater flow and sea-level rise allow saltwater to push upstream, shrinking suitable freshwater habitat for some species in lower reaches.
- The river frequently floods — not a primary cause. Native species are adapted to the Ganges’ seasonal floods; while extreme floods can cause local mortality or habitat changes, flooding itself is not the main reason for the dolphins’ endangered status.

Main threats to the Ganges river dolphin listed by conservation groups are pollution, river fragmentation and flow reduction from dams/barrages, entanglement in fishing gear and deliberate killing, prey depletion, boat traffic and habitat degradation; invasives and saltwater intrusion can add pressure in some areas.