Animal rights activists have welcomed the shipping giant's decision to change course in Sri Lankan waters to avoid collisions with blue whales, the world's largest mammal, AFP reports.

The island's southern coast has an unusually high density of blue whales, endangered on the IUCN Red List of Threatened Species, and is one of the busiest international shipping lanes in the world.

Activists believe that more than a dozen giant animals - the largest ever to live on Earth, up to 30 meters long and weighing 150 tons -- have died in collisions with commercial ships over the past decade.

International activists and local environmentalists have for years demanded that authorities move shipping lanes from east to west 15 nautical miles farther offshore.

The Geneva-based Mediterranean Shipping Company (MSC), one of the world's largest container carriers, announced that it has voluntarily adjusted its routes around Sri Lanka by that distance to reduce the risk of accidents involving whales, dolphins and porpoises. The company said the move could reduce the risk of collisions by 95 percent.

It has also ordered its small feeder vessels in the area to reduce speed to 10 knots in blue whale habitat.

The International Fund for Animal Welfare welcomed the announcement, calling it good news for blue whales and people alike.