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No longer in a pickle in Madagascar

Sea cucumber rearing is proving a success (Garth Cripps)
Sea cucumber rearing is proving a success
Garth Cripps

Villagers in the remote Madagascan village of Ambolimoke have just sold their first batch of commercially-reared sea cucumbers. These coastal people or "Vezo" have harvested wild sea cucumbers for export to Southeast Asia since the 1920s, but after a collapse of wild stocks in recent years, this is the first time they have been farmed.

Sea cucumber catches in Madagascar peaked in 1994 at some 650,000 tonnes of processed product, known as "trepang", most destined for export to Singapore and Hong Kong. At a price of US$4,000 per tonne, the returns were good for fishermen, who could expect to earn around US$1-2 for collecting 10 kg of good quality cucumbers. At the time, they were often able to collect several hundred kilograms - and net themselves a month's wages - in a single day.

But since 1995, while demand on the international market has remained strong, overfishing has caused a significant drop in the quality of the Malagasy trepang. Despite divers collecting ever smaller specimens and extending their harvest zones into deeper waters, annual exports had slumped to just 40,000 tonnes by 2004. As well as resulting in greater levels of poverty among the Vezo, this also caused great ecological damage as sea cucumbers are vital to the health of coastal ecosystems due to their appetite for organic detritus.

Responding with relish

To address the problem, an alliance of scientists from Belgium and Madagascar started researching the possibility of rearing the Holothuria scabra sea cucumber variety in open water (mariculture). This particular variety was chosen due to its high commercial value and because it is naturally found in the shallows of coral lagoons, often within beds of sea grasses. And, as a species of the shallows, it has been particularly over-collected.

Juvenile sea cucumbers used to stock the pens (Blue Ventures)
Juvenile sea cucumbers used to stock the pens
Blue Ventures

The scientists faced a series of problems in bringing Holothuria scabra into culture. Just finding mature adults to obtain gametes was difficult, and then the adults had to be induced to spawn. Next, scientists had to learn how to feed the sea cucumbers through their larval stages into adulthood. Growing sea-cucumbers in submerged pens finally began in 2007.

Once the research phase was complete, the project moved into the commercial stage. With the assistance of marine conservation organisation Blue Ventures, the young sea cucumbers were distributed to 25 family businesses in Ambolimoke. Each family constructed four pens in the first year, with each 12.5m sq pen initially stocked with 300 juveniles. Some businesses were assisted by "loans" of young sea cucumbers - which have since been paid back from the sale of adults.

With the growth cycle taking approximately a year, and with stocking and subsequent harvesting occurring every three months, it is hoped that each pen will provide a family with a net revenue of around US$180. By the end of 2010, it is expected that over 750 people will benefit directly from income derived from this new activity.

Scaling-up

The pilot mariculture project that supplied the juveniles to Ambolimoke's sea pens resulted from a partnership between the University of Toliara and local fisheries exporter Copefrito. These partners, together with two Belgian universities, have since formed Madagascar Holothurie, a private company cultivating large quantities of juvenile sea cucumbers in vitro prior to transplantation to locally-owned village hatcheries like those in Ambolimoke. Copefrito buys and exports the sea cucumbers, collecting and transporting them on ice down the coast to the processing plant in Tolear.

A view of the Madagascan coastline where sea cucumber farming has taken off (Blue Ventures)
A view of the Madagascan coastline where sea cucumber farming has taken off
Blue Ventures

Madagascar Holothurie aims to increase production to 200,000 juvenile sea cucumbers per year over the next five years and, through collaboration with NGOs like Blue Ventures, establish sea cucumber farming as a viable source of income for impoverished coastal communities. Seaweed cultivation is also being considered as an option in the region.

Georgina Robinson, marine scientist and coordinator of Blue Ventures' mariculture projects in Madagascar, is upbeat: "Sea cucumber farming provides an ideal alternative livelihood for the Vezo people - it's an activity that fits easily into their daily lives, which are based around the sea," she says. "It's relatively simple, with minimal labour and low capital investment, and has no adverse impact on the environment; in fact the pens also help to regenerate natural populations of sea cucumbers."

Written by: Richard Scrase

Date published: March 2009

 

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