Endangered dolphins survive in a Bangladesh river so polluted it’s ‘not livable’ for fish

A year-long survey found at least 20 endangered Ganges river dolphins still living in Bangladesh's Buriganga River, despite pollution levels researchers describe as not livable for native fish. Scientists observed the dolphins in 10 of 12 survey months, with calves making up nearly 16% of sightings, suggesting the small population is still reproducing.

Researchers say heavy metals including lead, chromium, and cadmium routinely exceed WHO safety limits in the river, which absorbs untreated waste from tanneries, textile plants, battery factories, and sewage. Native fish have largely vanished, but invasive South American suckermouth catfish have multiplied in their place, and scientists believe the dolphins have adapted their diet to hunt them.

A separate nationwide survey by Bangladesh's Forest Department and WCS Bangladesh counted 2,307 Ganges river dolphins across the country's rivers. Study authors say protecting the Buriganga population requires stopping industrial discharge and destructive fishing, not simply marveling at the dolphins' resilience.

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