Giants in our backyard: Why Sri Lanka's Blue Whales matter to the world

Standing on the southern tip of the island at Dondra Head, where the Indian Ocean stretches endlessly in every direction, it is difficult to imagine that beneath those restless blue waves lies one of the greatest wildlife spectacles on Earth.

- BY IFHAM NIZAM

Yet, according to Dr. Ranil Nanayakkara, Sri Lanka today is not just another tropical island with pretty beaches it is one of the best places in the world to see blue whales, the largest animals ever to have lived on this planet.

"The waters around Sri Lanka are particularly good for blue whales due to a unique combination of geography and oceanographic conditions," Dr. Nanayakkara told The Island. "We have a reliable and rich food source, and most importantly, a unique, year-round resident population."

In a world where blue whales usually migrate thousands of kilometres between polar feeding grounds and tropical breeding areas, Sri Lanka offers something extraordinary a nonmigratory population of pygmy blue whales (Balaenoptera musculus indica) that stay around the island throughout the year. Instead of travelling to Antarctica, these giants simply shift their feeding grounds around the island, moving between the south and east coasts with the monsoons.

The secret lies beneath the surface. Seasonal monsoonal currents trigger upwelling of cold, nutrient-rich water, which fuels massive blooms of phytoplankton. This, in turn, supports dense swarms of Sergestidae shrimps - tiny creatures that form the primary diet of Sri Lanka's blue whales.

"Blue whales require dense aggregations of these shrimps to meet their massive energy needs," Dr. Nanayakkara explained. "And the waters around Dondra Head and Trincomalee provide exactly that."

Adding to this natural advantage is Sri Lanka's narrow continental shelf. The seabed drops sharply into deep oceanic canyons just a few kilometres from the shore. This allows whales to feed in deep waters while remaining close enough to land to be observed from places like Mirissa and Trincomalee - a rare phenomenon anywhere in the world.