Seaweed harvest V (Tanzania, Zanzibar)

In the shallow lagoons of Zanzibar, women cultivate Kappaphycus alvarezii and Eucheuma denticulatum, two varieties of red seaweed rich in carrageenan, a natural gelling agent highly prized in the global food, pharmaceutical and cosmetic industries.

Their cultivation follows a rhythm dictated by the tides: at low tide, they wade into the water up to their mid-thighs, unroll cords attached to wooden stakes, then attach seaweed cuttings to them at regular intervals. These "sea gardens" are left exposed to the light and nutrients of the water until harvest, three to six weeks later.

This meticulous and physical work constitutes a major source of income for thousands of women in the archipelago, who derive relative economic independence from it. But this sector is now weakened by warming waters, which make algae more susceptible to disease and slow their growth. To cope, some women are experimenting with deep-sea cultivation, which is much more demanding in terms of logistics and safety.