Women thrive thanks to sponge farming on Zanzibar

Even while fish stocks are depleting in Zanzibar and the warming ocean makes seaweed farming unprofitable, sponge farming is serving as a buffer against both climate and economic shocks for 13 women in Jambiani, a fishing village of about 9,000 on this island on the Indian Ocean coast. 

Nasir Hassan Haji (marine cultures photo)

Each woman completes a one-year training, learning how to swim, maintain their own sponge farm, and sell their product. They are growing about 1,500 sponges, which bob on thick ropes for months before the women harvest, clean and sell them to shops and tourists. 

The sponges offer an eco-friendly alternative to synthetic sponges. They are more resilient to a changing climate than seaweed, need less maintenance and sell at higher prices to hotels and tourists. The sponges also filter and feed on particles in the water and provide an alternative to overfishing.

In a good month, they can sell 10 to 20 sponges for up to $20 each. When their sponges are of good quality, each farmer can make up to $200 a month – above the average income of most people in Zanzibar.

Marine Cultures photo

“I learned to swim and to farm sponges so I could be free and not depend on any man,” says Nasir Hassan Haji, the 46-year-old single mother of four children. “I am building my own house and educating my children,” she says. “Women were left behind before, but now that is changing.” She had farmed seaweed until 2015, when a friend told her about the environmental charity marinecultures.org.

There aren’t many sponge farms in the world, and there weren’t any in Zanzibar before Swiss citizens Christian Vaterlaus and Connie Sacchi built their home there in 2007 and began looking for ways to help the seaweed farmers who sometimes earned only $30 to $40 per month because seaweed prices on the world market were so low. Yet living costs in Zanzibar keep growing due to tourism. 

“We thought there must be better marine products that guarantee a better income and quality of life for the coastal community,” says Christian, who worked as a project manager and business developer before moving to Zanzibar.

During a research trip in the Asia-Pacific region, they visited the Marine and Research Institute of Pohnpei, which works with the indigenous coastal villagers of Pohnpei to farm sea sponges sustainably. MERIP partners with the Micronesian community to enhance their livelihoods while protecting their natural resources for the next generation.

Back in Zanzibar, the couple started their first sponge farm in 2009. They tested more than 120 species before finding an intertidal sponge that could be cultivated sustainably by using sponge fragments as seeds. Then they slowly collected sponge particles from around the island to build up a nursery stock so the farming wouldn’t harm the natural stocks. Now they have more than 10,000 sponges with which to scale up the farming.

They are expanding to three sites in Tunisia, thanks to winning the Blue Champions Award in mid-2021. Late in 2020, the Institut National Des Sciences Et Technologies De La Mer of the Ministry of Fisheries of Tunisia sought help in showing Tunisian fishers how to culture sea sponges.

The plan, Christian explained, is to start nursery farms in three communities and see if the fishers are interested. That means making the business case that sponge farming offers a much better prices for farmed sponges than for poached wild sponges. When the stock in the nursery is big enough, “we can start to teach them the farming techniques”, he says.


As oceans warm, Zanzibar’s women sea farmers grow sponges to stay afloat. Thomson Reuters, Aug. 4 2021

Restorative aquaculture: Marine Cultures. The Fish Site, Jun. 24, 2021

A spongy success story from Zanzibar. Make the Ocean Great Again, Apr. 9, 2018

Cover image: Sponge farm. Marine Cultures photo