Women in Jambiani, Zanzibar have shifted from seaweed to sponge farming after rising sea temperatures, overfishing and pollution undermined traditional livelihoods. A Swiss NGO, Marine Cultures, launched a pilot in 2009 and the practice has grown into a cooperative that can support farms of up to 1,500 sponges. Natural sponges — valued for personal care and reef benefits — can sell for as much as $30 each, helping families boost incomes while aiding reef recovery.
From Seaweed to Sponges: Zanzibar Women Turn Warming Seas into New Livelihoods
Women in Jambiani, Zanzibar have shifted from seaweed to sponge farming after rising sea temperatures, overfishing and pollution undermined traditional livelihoods. A Swiss NGO, Marine Cultures, launched a pilot in 2009 and the practice has grown into a cooperative that can support farms of up to 1,500 sponges. Natural sponges — valued for personal care and reef benefits — can sell for as much as $30 each, helping families boost incomes while aiding reef recovery.
02:27 PM, 11/13/2025Environment
Jambiani, Zanzibar — Around 10 each morning, women in hijabs and loose dresses wade into the island's shallow turquoise waters to tend rows of cultivated sponges — a growing livelihood born from climate disruption that devastated their seaweed farms.
Rising sea temperatures, overfishing and pollution have steadily degraded marine life around Zanzibar, eroding a traditional source of income for residents of Jambiani village. In response, many former seaweed farmers have shifted to sponge cultivation through a programme organised by the Swiss NGO Marine Cultures.
"Hot temperatures have killed seaweed, and declining fish stocks have driven many fishermen to quit," said project manager Ali Mahmudi. Unlike seaweed, sponges often tolerate warmer water and can be farmed on simple lines supported by poles that jut out from the shore.
Sponges serve both ecological and economic roles. They provide shelter and food for marine creatures and are valued as organic personal-care items for skin exfoliation. Depending on size, individual natural sponges can fetch up to $30, and a single farm can hold as many as 1,500 specimens. The US National Oceanic and Atmospheric Administration estimated the natural sponge market at about $20 million in 2020.
"I was shocked to learn that sponges exist in the ocean," said 53-year-old Nasiri Hassan Haji, who first discovered the practice more than a decade ago. A mother of four who once found seaweed farming labour-intensive with meagre returns, Haji learned to swim at 39 through an NGO programme and later joined a cooperative.
In 2009 Marine Cultures launched a pilot farm with widowed women in Jambiani to test sponge cultivation across the archipelago, where more than a quarter of the 1.9 million population live below the poverty line. Many women have since joined a cooperative to scale up production. "It has changed my life — I have been able to build my own house," said 53-year-old Shemsa Abbasi Suleiman.
Sponges and reef recovery
Beyond income, sponges bring environmental benefits. Studies indicate a sponge's skeletal structure supports carbon recycling within coral reef systems, while their porous bodies naturally filter and purify seawater. The United Nations estimates that roughly 60 percent of the world's marine ecosystems have been degraded or are being used unsustainably and warns the "ocean is in deep crisis." Sponges are also recognised for their potential to help restore coral reef habitats, which support about 25 percent of marine species and face severe threats.
For farmers like Haji, the appeal is clear: "What attracted me to this is the fact that we are not destroying the environment." Sponge farming in Jambiani therefore represents a practical example of climate adaptation that combines income generation with environmental restoration.