At least 20 endangered Ganges river dolphins persist in Bangladesh's heavily polluted Buriganga River, a 12-month study found after surveying a 27-km stretch. Dolphins appeared in 10 of 12 months, averaging groups of four with calves comprising about 16% of sightings. Researchers say invasive suckermouth catfish may sustain them, while industrial effluent and toxic heavy metals routinely push oxygen near zero, demanding urgent pollution control.
