Mangrove crab: Ecologically significant species with a promising economic prospect

Situbondo, one of East Java’s regencies, is situated on the north coast between Probolinggo and Banyuwangi, in Indonesia. The area is abundant with beautiful beaches, mountains, hills, forests, and rich history from the Dutch colonial period.

Sunail harvesting crabs and packing them in a "tail-down" position with their arms and legs folded inward toward their bodies to be sold in live conditions

Since 2000, Situbondo’s mangrove coverage has reduced significantly, largely due to large-scale conversion of mangrove forests into shrimp ponds and for milkfish aquaculture along the coast of Mangaran, a sub-district in Situbondo. This conversion and the absence of a coastal green belt have led to coastal erosion and a loss of around 50-100 m of land. Many fishponds have been destroyed by the coastal erosion, resulting in the loss of livelihoods for some communities.

To strengthen the resilience of ecosystem-dependent coastal communities, the socio-economic development of the communities living near the mangrove ecosystem is equally as important as the mangrove rehabilitation itself. A project in Tanjung Pecinan village, Mangaran, Situbondo, implemented by Samir Bamboo Conservation (SAMBACO) under a Mangroves for the Future (MFF) grant, aims to protect mangroves against sea abrasion through mangrove rehabilitation and livelihood development activities in Mangaran.

Crab fattening was identified as an alternative livelihood that could increase the income of communities in Tanjung Pecinan village. In crab fattening, wild-caught juvenile crabs weighing about 100-150 grams are put in floating bamboo cages that are 1m by 1.5 m in size. Every cage fits up to 40-50 crabs. The crabs are fed two times a day, in the morning and evening, for 20 days. After 20 days, the crabs weigh 200-250 grams and are ready to be harvested by community groups.  

Mangrove crabs packed in a "tail-down" position with their arms and legs folded inward toward their bodies to be sold in live conditions © Cynthia Nurcahya

Due to the high market value of crabs, some local communities catch and sell crabs to earn additional income. In the mornings, they work as farmworkers, or are porters at places for fish auctioning and at night they search for crabs.

When SAMBACO started the crab fattening initiative, the villagers were very enthusiastic and subsequently formed a farmers group. Theoretically, crab fattening is not that easy and the risk is quite high, but the production period is relatively short.

“It was almost impossible at first. However, through hard work, perseverance and learning crab characteristics inside the cage, we finally achieved a good result. Even though some juvenile crabs died during the process, we could still derive benefits from crab fattening thanks to the high market value of the crabs,” said Sumarwan, a crab middleman in Tanjung Pecinan village.

As a middleman, Sumarwan helps the farmer groups market and sell fattened crabs to bigger middlemen. Before Sumarwan joined the group, he facilitated the marketing of crabs by selling them to bigger middlemen or directly to consumers. He buys crabs from the villagers at a price ranging from IDR 40,000 – IDR 55,000 per kg depending on the size. “I buy crabs from villagers and pay them directly in order to help them market their products. Then I sell the crabs to the bigger middlemen or directly to consumers, where I sometimes receive instalment payment,” Sumarwan explained. After he joined the crab-fattening activity, he helped group members to sell the crabs to his network, bigger middlemen and direct consumer with a higher price.

35-year-old Sunail is a mud crab fisher. On a daily basis, he works with a boat owner to catch fish and at night, he catches crabs by using nets near fishpond dykes. If he’s lucky, he catches around 5 – 20 crabs per night.

The next morning, he sells the crabs to middlemen who then sell the crabs to markets in Situbondo and Probolinggo Since Sunail was introduced to the crab fattening activity, he has been able to sell his bigger crabs at a higher price. The crabs can be sold for around IDR 100,000 – IDR 150,000 per kg. After being introduced to the crab fattening activity, Sunail now earns approximately IDR 4,500,000-7,500,000  on average per month, 230% more than what they used to earn before the activity.  He has also been able to earn extra income from making the bamboo crab cages.  He occasionally receives order from community to build floating cage with the price IDR 1,500,000 of total work contracted.   

Harvesting mangrove crabs

From the crab fattening, local people have an alternative way to improve the marketability of the crabs they catch. From this activity, they can grow the crabs until they reach 250-300 g size. The crab price with that size is significantly higher, around IDR 100,000 – IDR 150,000 per kg. In the initial production stage, the net profit the group made was IDR 1,000,000 per month (with two production cycles). With hard work and perseverance, taking up crab culture or fattening in an eco-friendly way can raise the economic status of coastal communities.

The participatory approach to improve and strengthen community resilience that is central to the MFF resilience framework has proved that effective and sustainable ecosystem management solutions must engage individuals and communities.

Mangroves for the Future (MFF) is a partnership-based regional initiative which promotes investment in coastal ecosystem conservation for sustainable development. MFF focuses on the role that healthy, well-managed coastal ecosystems play in building the resilience of ecosystem-dependent coastal communities in Bangladesh, Cambodia, India, Indonesia, Maldives, Myanmar, Pakistan, Seychelles, Sri Lanka, Thailand and Viet Nam. The initiative uses mangroves as a flagship ecosystem, but MFF is inclusive of all types of coastal ecosystem, such as coral reefs, estuaries, lagoons, sandy beaches, sea grasses and wetlands. MFF is co-chaired by IUCN and UNDP, and is funded by Danida, Norad, and Sida and the Royal Norwegian Embassy in Thailand.

Go to top