Photo: Julio Curiano Jr, Admin Aide of the Bolinao Marine Laboratory inspects the giant clam nursery in Silaki reef, Bolinao Pangasinan. The Tridacna gigas are true giant clams which can readh over 100cm in shell length.

Photo by: Rem Zamora

Giant clam culture

The culture begins in the ocean nursery by inducing the giant clams that are 8 to 10 years old, to release sperm and eggs. These are then gathered and brought to the BML hatchery, where they are first put in larval rearing tanks and, after eight days, in concrete settlement tanks.

"We take care of them [for about five months] until they grow to about 5 centimeters (cm) in size. Then we bring them back out to the ocean nursery to enable them to grow faster," Conaco said.

Because they are vulnerable to predators, such as crabs and puffer fish, the juveniles have to be put in cages once they are transferred to the nursery, she said.

They are freed from the cages and laid on the seabed only when they grow to about 20 cm in size.

Challenges

Despite the success in bringing back the giant clam population, the project is still trying to hurdle certain challenges, according to Conaco.

"The big challenge I think is really getting the funds to get the personnel to take care of the clams," she said.

With the number of giant clams that they now have, many workers are needed to clean and take care of the clams and to bring them to the nursery. Algae had to be removed from the shells of the juveniles to enable them to get maximum sunlight and hasten their growth.

"Since we do not have much funding, so basically we just leave the clams to fend for themselves," Conaco said.

Julio Curiano Jr, Admin Aide of the Bolinao Marine Laboratory inspects the giant clam nursery in Silaki reef, Bolinao Pangasinan. The Tridacna gigas are true giant clams which can readh over 100cm in shell length. Photo by: Rem Zamora

At present, the giant clams are under the care of Julio Curiano Jr., BML administrative aide, who is also in-charge of the ocean nursery maintenance and stock enhancement.

"The other thing is, the nursery is far away from [BML], and we do not have anybody watching over it. So, at times, we lose some clams," Conaco said.

Silaqui Island, which is part of Barangay Binabalian, one of the villages of Bolinao's Santiago Island, is a sparsely populated community that is 30 minutes away by speed boat from the BML.

Community help

"But we would like to be more proactive in reviving the project and starting the production once again to spread the stocks [all over the country]," Conaco said.

The country's giant clam population, she said, should reach a level where giant clams are able to multiply on their own. "We need to have a population where the egg and sperm will find each other in the water to become baby clams," she said.

"Right now, we are starting to see this here [in the nursery]. This means that the stocks that we have are already reproducing on their own and we are starting to see the small clams all over the reefs."

Silaki Island in Bolinao, Pangasinan. The reef near the island serves as the nursery for Tridacna gigas, commonly known as giant clams mamnaged by the Bolinao Marine Laboratory. Photo by: Rem Zamora

The BML is now trying to work with the Bolinao town government to find a way to involve the Silaqui community in taking care of the giant clams, especially now that the nursery is being visited by tourists.

"We want tourists to enjoy the clams, to learn about these, but at the same time, we want to make sure these are protected by not touching or stepping on these," Conaco said.

"It's a big effort and I think one of the promising things is that Bolinao [council] has passed an ordinance declaring the town as 'Giant Clam Capital of the Philippines,'" she added.

Source: University of the Philippines Marine Science Institute

READ: A day in the life of a giant clam nursery worker