Overview

The whale shark is the world’s largest fish. Whale sharks appear in Donsol waters in considerable numbers between December and May of each year, taking advantage of dense food concentration. Donsol is the seasonal feeding ground for whale sharks. This gives scientists and conservationists the opportunity to understand more about them through research. The whale sharks’ arrival also prompted the local community to provide interaction tours. Now, visitors have the chance to swim alongside these majestic creatures.

The Area

Donsol is located in the Province of Sorsogon, in the Bicol Region of the island of Luzon, Philippines. The town’s population is estimated at 47,000 (2003 census) and is traditionally engaged in fishing and agricultural activity.

The Butanding

Whale sharks, known locally in Bicol as “butanding,” are known to grow to lengths of up to 18m, weigh up to 40 tons and live up to 100 years. In other parts of the Philippines, whale sharks are known locally as “balilan,” “kulwano,” “tawiki,” and “toki.” In Donsol waters, typical sightings of whale sharks are between 4-12m in length. Distinctive characteristics include: a broad, flat head, 3 prominent ridges on the upper flank, a checkerboard pattern of white spots and stripes on its blue-gray-brown skin. Whale sharks are highly migratory. Their movement may be guided by food availability, water temperature and quality, environmental factors such as weather, currents and winds. Where they go, during the off-season is still not known.

Feeding and Diet

Whale sharks are filter feeders, typically feeding on plankton, krill, small fish, squid and invertebrate larvae. The huge mouth (up to 2m across) is lined with thousands of tiny teeth, which are neither used for chewing nor biting. Large volumes of water are sucked into the mouth where the food is retained in the gill rakers, and the water is released through the gill slits. Its diet being varied and its food only flourishing in healthy conditions, the whale shark acts as an indicator of the sea’s general health.