New Hope For Sea Cucumber Fisheries

The sandfish Holothuria scabra – the most valuable of tropical species in a sea grass bed near Noumea.

With the charisma of a house brick, it's a wonder that sea cucumbers are attracting so much attention in the Pacific among funding agencies and fisheries departments. Once cooked and dried into bêche-de-mer, this export commodity has brought good money to Pacific Island communities for more than a century.

The market is China-and the demand for bêche-de-mer has been booming for the past decade. Sea cucumbers are cooked and dried in much the same way as when fishing in the Pacific began in the 19th century, inspired by traders from the East. Export prices of up to US$50 per kg have been the driving force for the increasing fishing pressure on tropical sea cucumbers. They feed on decaying material in sand and are important for coastal ecosystems. Harvesting is traditionally by fishers at a small-scale, but commercial operators are now fishing more extensively.

Sea cucumber stocks are easily depleted by heavy fishing pressure so many Pacific countries, such as Samoa, Fiji and Tonga, have placed moratoria on fishing sea cucumbers to allow stocks to recover. Tragically, some species don't recover quickly from over fishing. The question now is how to regain enough breeding animals in the wild to allow them to reproduce and rebuild inshore fishing grounds?

Through funding from the Australian Center for International Agricultural Research (ACIAR), WorldFish Center commenced a research program on sea cucumbers in 1995. It aimed to develop technology for rebuilding depleted sea cucumber stocks by culturing and releasing the juveniles into the wild.

The first phase in the Solomon Islands established methods for culturing the most valuable species, called the sandfish. The second phase of the project in New Caledonia, which is in partnership with the Secretariat of the Pacific Community, has secured additional funding from the three New Caledonia provincial governments and the government of France. It focuses on how to release hatchery-produced sandfish juveniles in the wild so they survive in high numbers.

Thousands of juvenile sandfish were produced in the hatchery in 2003-a first for New Caledonia. A genetic study was first completed to ensure that the hatchery-produced juveniles would be released into populations of similar genetic make-up to that of their parents.

The first experiments, using juveniles 2 cm (0.8 inches) in length, revealed the best transportation methods, and the optimum habitats and best times for release into the wild. Temporary enclosures were useful for protecting the juveniles from predators in the first month after release, when they are adjusting to the natural environment.

WorldFish Center's project is also assessing the potential to grow sea cucumbers with shrimp in earthen ponds, in collaboration with researchers from the French Research Institute for Exploration of the Sea (IFREMER). The first experiment was promising, finding that the juvenile sandfish can grow with small shrimp and do not affect their growth or survival. Further experiments will need to test the co-culture at various stages in the shrimp culture cycle. Sandfish could provide a by-crop for shrimp aquaculture and an environmentally friendly approach because they eat waste products from the shrimp, which would otherwise be discharged nutrients.

The project's vision is to provide reliable methods for restocking sea cucumbers in coastal fishing grounds. The final phase of WorldFish Center's program will test the effectiveness of this approach by releasing large numbers of hatchery-produced sandfish juveniles at a number of sites. Their survival will be monitored until a size at which they can reproduce naturally.

A UN Food and Agriculture Organization-funded workshop in China in October of 2003 stressed a conservative approach to managing sea cucumbers. But the strengthening of the market creates more incentive for exploitation. As an example, a recently opened fishery in Egypt took only four years to bring species, like the sandfish, to local extinction.

Sustaining these fisheries will only come about when the restocking is combined with sensible management. Whether restocking technology can save wild stocks of sea cucumbers will depend on the willingness of the people and government to protect some areas from fishing. At least at the research stage, this seems possible.

Dr. Steve Purcell is Project Leader of the sea cucumber restocking in New Caledonia for WorldFish Center and the SPC. WorldFish Center's vision is to eradicate poverty and bring food security to the poor through research on the management of aquatic resources. For more information, check the project's Web site at: (www.worldfishcenter.org)