Against the odds, endangered dolphins survive in Bangladesh’s polluted river

Researchers surveying Dhaka's Buriganga River, a 29-kilometer waterway so laced with tannery waste, sewage and heavy metals that native fish have largely vanished, found roughly 20 endangered Ganges river dolphins persisting there anyway. The year-long study tracked the animals across ten of twelve months, with calves making up nearly 16% of sightings, suggesting the dolphins are not just surviving but reproducing.

Scientists believe the dolphins are surviving by hunting invasive, pollution-tolerant suckermouth catfish, since virtually nothing else can live in water where dissolved oxygen drops near zero. A national survey found just 27 dolphins across five heavily polluted rivers including the Buriganga, part of a broader national count of 2,307 dolphins across the country's waterways.

Experts quoted in the piece say the dolphins' continued presence is not evidence the river is fine, but a signal that conservation efforts need to address both pollution and illegal fishing nets, plus heavy vessel traffic disrupting the animals' movement.

The full dispatch is available from the source below.