Tuesday, 4 November 2008

Tokoriki Diving, Fiji: Tokoriki Diving: Clams Fight to Stay Alive

Clams Fight to Stay Alive


Tourists who dive and snorkel in Fijian reefs are fascinated with the unique giant clam. To them it symbolises how exotic the South Pacific is.

According to the Fisheries Department: this magnificent creature can live up to 200 years and grow to the size of a bathtub or two metres long if it reaches full maturity. In fact, some islands in the Lau Group still use the shell of this species, tridacna gigas, as babies’ baths.

Unfortunately, excessive human consumption led to the species’ extinction and endangersed another species, tridacna derasa or smooth clam in the 1960s. It was reintroduced to Fiji from Australia’s Great Barrier Reef in a joint venture between the Fijian and Australian Fisheries Project.

Last month, the Dive Tropex at Tokoriki Island Resort in the Mamanucas, with the help of the Ministry of Fisheries, began a project aimed at conserving this fascinating yet fragile species. The project, known as the Tokoriki Island Giant Clam Regeneration Project, is a significant step as the giant clams are the first of their species to be reintroduced to Western Fiji after becoming extinct.

Will Wragg, 28, and Alexandra Garland, 30, dive instructors at Tokoriki, realised the importance of implementing such projects as reefs and pinnacles surrounding the island did not have any more giant clams.

It takes a giant clam between seven to nine years to reach full sexual maturity but chances of successful reproduction are very slim. In addition to the odds stacked against the giant clam, it suffers heavy predation in its early years.
Ms Garland said apart from conservation purposes, the project would add another dimension to diving, as the presence of clams in dive sites would make it a more interesting experience for guests.

The giant clam is not the only species planted around the island. The smooth clam and the tridacna squamosa or fluted clam have also been planted. These clams, totalling up to 104, were supplied by the Fisheries Research Station on Makogai Island in the Lomaiviti Group. A team of marine biologists at the station artificially seed and nurture various species of clams before planting them on Makogai Island’s fringing reefs. To survive the long journey from Makogai to Tokoriki, the clams were wrapped in medical gauze dampened with seawater and placed in sealed heavy-duty bags, which were arranged, in a chilled icebox.

Upon reaching Tokoriki they were removed from the bags and placed in buckets of sea water before being measured and catalogued. Three officers—Aisake Batibasaga, Peni Drodrolagi and Kolinio Rakaka from the Fisheries Department—along with the two PADI instructors deep dived around various sites near the island to find suitable places planted in deeper waters to plant the clams.

The clams were carried down to cages with a base of dead coral rubble where they were placed in catalogue order. The baby clams nestled into the coral base and the cages were closed and wired down. The cages protect the clams from predators such as the octopus and the triggerfish. The small clams, which are four to six centimeters long, are planted in one to five metres deep waters as they need a rocky base and a lot of sunlight to grow. The bigger ones are planted in deeper waters measuring seven metres in depth at least.
Once the clams reach one year of age they will be taken out of their cages and planted on the reef.

Ms Garland said guardians of the clams will be appointed from the local Fijian population to help protect and conserve all planted clams. The project aims to breed erate the giant clam as a species.

It focuses on providing the local Fijian population with incentives to initiate similar programmes carried out for research purposes.

Tokoriki Diving, Fiji: Tokoriki Diving: Clams Fight to Stay Alive

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