Giant Clam Culture To Help Conserve Marine Heritage

Haslin Gaffor Bernama 23 Dec 11;

This is the second of two articles on conservation efforts at Sabah's Tun Sakaran Marine Park

SEMPORNA, Dec 23 (Bernama) -- The Giant Clam Culture Centre on Buhey Dulang Island plays a vital role in conserving the marine ecosystem at the Tun Sakaran Marine Park off the coast of Semporna, Sabah.

The centre, the first of its kind under Sabah Parks, conducts research and cultures giant clams with seeds supplied to the local community to help them reduce their over-reliance on natural marine resources.

The centre, established in 2006 under the Semporna Islands Darwin Project, is the result of cooperation between Sabah Parks and the Marine Conservation Society-United Kingdom.

Sabah Parks' Marine Research Officer Nasrulhakim Maidin noted that the culture centre serves as an attraction where outsiders can learn more about the clams.

"Giant clam culture is important because their numbers have depleted from over-harvesting around the waters of Semporna," he told Bernama during a visit to Buhey Dulang Island of the coast of Semporna.

The giant clam is a mollusc in the Bivalvia class that thrives in Indo-Pacific waters.

There are seven species of giant clams in Malaysian Waters, and some can grow up to 60cm in length.

According to Nasrul, giant clams not only thrive on plankton but also produce their own nutrients through photosynthesis, with the help of the algae.

"The giant clam plays an important role in the marine ecosystem as it filters the water," he said.

SEEDING THE CLAMS

So how to culture the giant clams? First, the giant clam brood stock is selected and its size is recorded for future reference.

Then the clam shell is cleaned with a nylon brush and numbered for future reference. The seeding is done by injecting diluted serotonin, a hormone, to stimulate spawning.

Within minutes, the giant clam stock reacts and produces eggs and sperm that are collected in big plastic bags to fertilize in a few days.

Six months after hatching, the seed is released into the sea within the reef area, initially in cages to protect them from predators.

The seeds that hatch at the centre are mostly relocated near Ribbon Reef, an area within the national park allocated for education on marine life.

COMMERCIALISING THE GIANT CLAM

In the long term, said Nasrul, there were plans to commercialise the giant clams for ornamental purposes as well.

Even now, many parties have indicated their interest in buying giant clams but locals are being given priority to sell them.

"We give the seeds to the locals, who will breed them for one or two months before they are ready for sale or export," he said.

CONSERVING THE GIANT CLAMS

Elvin Michael Bavoh, a marine officer at Tun Sakaran Marine Park's first research and culture centre, noted that so far about 2000 seeds have been relocated to the surrounding areas.

Another 1,000 seeds are waiting to be relocated from the centre.

He pointed out that the effort to culture giant calms in concentrated on two species -- tridacna gaigas and tridacna derasa -- which are fast diminishing in the waters of Semporna.

Currently only the tridacna derasa is being cultured with the brood stock from the waters of Semporna, while preparations are being made to culture the tridacna gaigas with brood stock from the Philippines.

Breeding the giant clams is no easy job, calling for close monitoring, because giant clams are easy prey to natural predators and humans.

In August, several of sea nomads known as Palauh, living around the waters of Semporna, were seen picking relocated giant clams not far from Buhey Dulang island, but they were stopped in time by park workers.

Preventing these giant clams from being stolen is a serious challenge for employees at the centre, and the park relies on cooperation from the islanders in conserving both the clams and, in the bigger picture, the marine heritage at Tun Sakaran Marine Park.

-- BERNAMA