Blue whale population in Lankan waters shows rapid decline

The blue whale population that has lived for many years in the coastal waters of Sri Lanka, has shown a rapid decline in their sightings in recent years, said a report published by the Mongabay yesterday.

- 

"With multiple pressures on these massive creatures — from ship traffic on one of the world’s busiest shipping lanes, to disturbance from whale tourism, pollution and surface sea temperature rise and climate change — there are several possible factors for the disappearance of the whales," it said.

For decades, the North Indian Ocean has been known to have its own distinct population of blue whales (Balaenoptera musculus). They have their own vocalisation or dialect, distinct from other blue whale populations. They also spend all year in warm waters, unlike most other blue whales, who migrate to feed in cold waters and breed in warmer seas, says Asha de Vos, a marine biologist and founder of Oceanswell, a marine conservation research and education center in Sri Lanka.

De Vos told Mongabay that the North Indian Ocean blue whales are “grazers not gorgers,” feeding throughout the year. The coasts of Sri Lanka, and particularly the southwest coast between Galle and Dondra, has long been a hotspot for this resident population.