Whale sharks in Batangas fresh waters

Alcuin Papa, Philippine Daily Inquirer 8 Feb 09;

MANILA, Philippines—For the first time, the gentle whale sharks, locally known as “butanding” are venturing into the fresh waters of the Batangas province.

Paolo Pagaduan, World Wildlife Fund (WWF) project manager for a coastal management undertaking in Nasugbu, Batangas, said increased environmental awareness and vigilant efforts against dynamite fishing and overfishing are encouraging the proliferation of whale sharks and other marine species in the area.

Pagaduan told the Philippine Daily Inquirer that a 15-foot whale shark was spotted feeding in the estuaries of the Calayo River in Nasugbu last November. Estuaries are areas where fresh water meet seawater.

Pagaduan said the gentle sharks are feeding on krill (alamang) in the mouth of the river which is part of the Hamilo Coast.

“The presence of large filter feeders such as whale sharks and manta rays could indicate the return of a strong food base. The creatures are probably attracted to the swarms of krill or plankton that feed on the nutrient-rich runoff from nearby Calayo River,” Pagaduan said.

For years, fisherfolk living on the coasts of Nasugbu have spotted the butandings in the area. But this is the first time the gentle butanding (Rhincodon typus), the world’s largest fish capable of growing to over 40-feet long, are moving into freshwaters.

“This is highly unusual. Whale sharks do not normally feed in shallow estuaries,” Pagaduan told the Inquirer.

Whale sharks have been known to aggregate in Donsol, Sorsogon. But Pagaduan said more and more sightings of the animal are being reported in Nasugbu and Anilao in Batangas.

At present, sightings of manta rays and the Oliver Ridley sea turtles are increasing, he said.

“Usually, these species never stay more than a few days. But it seems they are staying longer,” Pagaduan said.

He credits the increased presence of the marine animals to thriving numbers of krill in the area which feed on plankton.

The proliferation of the krill and plankton, Pagaduan said, are largely due to the cessation of dynamic fishing in the area, the increased awareness of fisherfolk living on the coast and the partnership between local residents, local government officials, the private sector and nongovernment organizations to protect the coastlines.