MIRISSA, Sri Lanka — Sri Lankan waters are considered a haven for the largest creatures ever to have lived, the blue whale, a rare place for a resident, year-round population to thrive.

Eventually, the International Whaling Commission, the intergovernmental body dedicated to protecting whales, recognized Sri Lanka’s blue whales as a distinct subspecies called Balaenoptera ...

A resident population of blue whales has for many years lived in the coastal waters of Sri Lanka, but in recent years sightings of the animals have declined rapidly. With multiple pressures on ...