As oceans warm, Zanzibar’s women grow sea sponges to stay afloat

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The sponges are more resilient to a shifting climate than seaweed, need less maintenance and sell at higher prices to hotels and tourists, offering an eco-friendly alternative to synthetic sponges.

Nasir Hassan Haji never thought of herself as a farmer or a swimmer, but as she waded into Zanzibar’s blue waters with goggles pulled over her headscarf to examine her floating sponge farm, she realised she had surprised herself by becoming both. Alongside 12 other women in Jambiani village on the Indian Ocean coast, Haji has come to rely on the climate-resilient, natural sponges bobbing on thick ropes where they grow for months before the women harvest, clean and sell them to shops and tourists.

“I learned to swim and to farm sponges so I could be free and not depend on any man,” Haji said later, sitting on the floor in her home on the Tanzanian island. Before farming sponges – which resemble a white, textured rock but are actually simple, multicellular animals – Haji cultivated seaweed, until increasing ocean temperatures fuelled by global warming made it difficult to grow her cash crop. Haji and other women dependent on the ocean for their livelihoods – from seaweed farming to fishing and tourism – have seen warmer, rising seas threaten their work, but they are adapting by finding ways to diversify what they do to get by.