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Blue carbon sea cucumber ranching

Selayar Islands, one of the largest archipelagos in Indonesia. Credit - CSERM UNAS.

Pastures new and blue: Blue carbon sea cucumber ranching in Sulawesi's seagrass meadows

Indonesia is a global hotspot of coastal biodiversity; a sprawling archipelago including more than 17,000 tropical islands. Yet the nation's growing population and demand for resources is placing increasing pressure on coastal habitats, from mangroves to mud flats, coral reefs, and seagrass meadows. While overfishing threatens marine populations of tuna and other large species, coastal waters are threatened from all sides by development projects, pollution, prop scarring (damage caused by boat propellors), illegal fishing using bombs or poison, and the overexploitation of their more easily accessible resources.

In South Sulawesi's Selayar Archipelago, as across much of the country, it's the men who head out on fishing expeditions, often for weeks at a time. This leaves the island's coastal seagrass meadows primarily in the hands of their wives and daughters, both as custodians and collectors of everything from crabs and snails to sea cucumbers. Empowering women with the skills to sustainably manage and utilise the resources of these critically carbon-rich and biodiverse habitats, is an essential step towards truly comprehensive conservation of Indonesia's uniquely rich seas.

Seagrass meadows are a frequently overlooked marine habitat, occupying a relatively narrow area between the land and the sea. While at first glance they may seem unremarkable, they are in fact a biodiversity hotspot, providing nurseries for up to 20% of the world's most important commercial fish species, as well as countless other seagrass specialists such as rays, sea horses, crustaceans, molluscs, and other invertebrates. They also play a crucial role in maintaining the water quality necessary for healthy growth in adjacent coral reefs, indirectly supporting some of our planet's most vibrant ecosystems, and absorbing so much atmospheric carbon per square metre, that they are often referred to as 'blue forests.' Much like the mangrove forests they are often found near, the secret to seagrass' staggering productivity lies in the constant fluctuations of high and low tide which define their ecology, providing niches and opportunities for myriad different species within every 24-hour cycle. Though found only in shallow, well-lit, coastal waters, it is when the tide is at its lowest that foragers from Selayar's coastal villages descend to harvest the seagrass' riches, gleaning (collecting) everything from crabs and lobsters to seaweed, and, of course, sea cucumbers.

Seagrass in Selayar, dominated by Enhalus acoroides. Credit - CSERM UNAS.

They may be a rather unassuming species to look at, but sea cucumbers are among the most important residents of any tropical seagrass meadow. They are typically the largest permanent residents and the largest contributor of faunal (animal) biomass by weight, playing a vital role in the cycling of nutrients and oxygenation of sediments through their regular habit of burrowing, both of which support healthy growth of the seagrass itself. Not only that, but many species fetch a high price on international markets, utilised for everything from food and medicine to various cosmetic ingredients. Unfortunately, this also means they are frequently overexploited, a pattern which exhausts local populations and ultimately undermines the integrity of the seagrass ecosystems they help to shape. Maintaining viable sea cucumber populations in their natural habitats is therefore an important part of wider efforts to conserve seagrass, and an opportunity to engage local communities in stewardship of these unique marine meadows.

Black sea cucumber (Holothuria atra) found in Selayar coastal area. Credit - CSERM UNAS.

As part of our Darwin Initiative project, the Centre for Sustainable Energy and Resources Management at Universitas Nasional (CSERM), Indonesia is piloting sustainable sea cucumber ranching in Selayar's seagrass meadows, part of the Takabonerate-Kepulauan Selayar Biosphere Reserve. The project aims to bridge the gap between local interests and global concerns via an innovative approach to producing one of the world's most sought-after seafood specialities - white sandfish (Holothuria scabra). Our field teams are conducting ongoing and comprehensive habitat assessments to identify ideal locations for developing this semi-wild approach to aquaculture, in which sea cucumbers are released into coastal seagrass meadows, monitored and managed by local residents, before being harvested for sale and processing. By ensuring a stable population of these important invertebrates in their natural habitat, this project not only protects an endangered species and the ecosystem which they help sustain, but will also provide significant income for Selayar's women at a time when overfishing and population pressures leave households which are entirely dependent on fishing, increasingly vulnerable.

Sandfish (Holothuria scabra) reared in PT SPK, Lombok. Credit - PT SPK (Sejahtera Putra Kusuma), CSERM UNAS.

Meeting the needs of all the stakeholders in this project involves innovation at every stage, from modifying established methodologies to suit the specific hydrological and ecological conditions of Selayar’s coastline, to building partnerships with the private sector and government institutions. We have been working with a well-established sea cucumber producer to develop a ‘grow-out and buy-back’ model. This model aims to ensure fair and predictable income for participants as well as with local development agencies and the Marine and Fisheries Ministry to ensure necessary support for integrating blue carbon sea cucumber ranching into the regional economic system. The intention is to develop a bottom-up framework for sustainable utilisation of seagrass meadows with support at every level, and in-built incentives to ensure that the value of these vital blue carbon sinks is recognised for the benefits it brings to local residents, as well as the global community.

Pen culture in Selayar. Credit - CSERM UNAS.

Darwin Initiative funding has been instrumental in our ongoing efforts to realise a new model of coastal conservation for Indonesia's small islands, reconnecting the economic interests of local communities with the health of the ecosystems on which they depend.

A woman’s world: A personal story from a project staff member, Qurratu Ainin

Women from fishing families in the Selayar Islands are familiar with coastal areas. Since their teenage years they have actively gleaned with friends to fulfil their nutritional needs; something which can become a hobby. It is through gleaning that women in the Selayar Islands become familiar with the various types of plant and animal life found in coastal areas, particularly in areas of seagrass ecosystems.

"As women become more active in the Selayar Islands, their positive impact will be felt across various levels of society."

Sea cucumbers are one of the species often found, however since becoming a ‘premium’ or high-value food item in various other regions around the world, their high export value is seen more favourably than their immediate nutritional potential by those gleaning.

When communicating with the public about sea cucumber rearing activities, there was a particularly positive response from women. With the high economic value of sea cucumbers, especially sandfish, the community is excited to participate in this activity. Women often encounter sea cucumbers and have a keen interest in them, despite their limited knowledge about the creatures. This enthusiasm for learning motivates me to engage in activities that will have a positive impact on society.

Women from fishing families, who typically rely on coastal resources from gleaning to meet their family's food needs, will enhance their income by engaging in sea cucumber rearing activities. This will in turn support the implementation of women's empowerment, which will have a positive impact on the welfare of society as a whole. Women will also play an important role in the family by increasing their contribution to the family income. This enables them to form families with good welfare and access to resources and education, which in turn optimises the potential for their children’s future success. I am confident that as women become more active in the Selayar Islands, their positive impact will be felt across various levels of society.

Written by Christopher Kelly. For more information on this Darwin Initiative Main project 30-025, led by the Centre for Sustainable Energy and Resources Management (CSERM), please click here.