This article appears in Vol. 33: Collective.

Paje Paje is serene in the moments before sunrise. The tide is often out, the air is salty fresh and an amber glow tints the mirror-flat sea. It is as if the village's best features are accentuated at dawn. I've experienced it both after a good night's rest and on the walk home from a Saturday-night party. The edges of the clouds appear to be embossed in gold.

Between the villages of Bwejuu and Jambiani on the southeast coast of Zanzibar, Paje's blue-green waters, African cultures and reliable trade winds make it a popular holiday destination, especially for kiteboarders. The expansive lagoon has a sandy bottom and is shallow at low tide, with a reef that wraps around the perimeter protecting the water from crashing waves.

There are sights and sounds I've become familiar with on the beachfront: the whirl of a kite forming a figure of eight in the air, the thud of a football being kicked, the repetition of "hakuna matata" and the clobbering noise of calamari being tenderised. But in the early mornings, the lapping of the ocean and the irregular squawking of crows are about the only thing you'll hear. While my alarm usually goes off at around 6am, some days I find it hard to get out of bed having gone to sleep far too late the night before. The seaweed farmers, however, are always up at daybreak. Their livelihoods depend on it.

While Zanzibar is perhaps best known as "Spice Island" thanks to its spice-farming heritage dating back to the early 18th century, seaweed farming was introduced to Zanzibar in the 1980s, motivated by the thriving trade of seaweed in Indonesia and the Philippines. Today, the industry is driven by women, "mamas", as a result of the fact that Tanzanian women have historically not enjoyed the same opportunities as men. The work is labour intensive and, for it, the average farmer receives the equivalent of about £18 per month. Many men don't think this worth their while and seek more profitable opportunities in fishing or tourism. But the women stick with it, owning it.

Though it is used locally to make skincare products, Tanzania's seaweed is largely exported to the US, Denmark, Sweden, the UK and China, where it's processed for cosmetics, medicines and food. Regardless of its destination, it has proved a liberating force on the predominantly Muslim island. Until recently, women often only left their houses for funerals, weddings or to visit the sick, their isolation reflected even in the architecture of their homes, where stone benches at their front doors allow men to receive visitors without compromising the privacy of their women. Initially some husbands threatened divorce, not agreeing with the liberation of their wives, but it made increasing economical sense and it is now a way of life. Farming means that, instead of being reliant on men for money, women can buy their own food and stand a better chance of being able to cover the cost of both raising children and family medical bills. Seaweed represents independence.

When the tide is low the women are at work; when it is high, they are back at their houses tending to the families. In time with the waves, I head to the beach in search of the mamas. Much like they have to visit the ocean everyday to see if the water conditions are right for farming, I find myself on standby too, checking to see if anyone is out there. On the days I see them at work, I wade out in the lukewarm water and introduce myself.

A day in the field sees the women crossing acres of damp, white sand before reaching their sheltered farms where their produce grows. Dozens of neat, parallel kamba (ropes) are staked into the ocean floor. The women collect floating seaweed which they tie to the bright ropes in a rhythm that seems like second nature. Warm water whirls around their long dresses, which glow with an opaqueness in the sunlight.

When their work is done, they walk home with their skirts clinging to their legs, balancing the sacks heavy with seaweed on their heads. Outside their homes or at the community centre, they sort their beautiful harvest of purple, red and green in the sun and leave it to dry.

I visit the community centre, where I join the women seated on straw mats, chatting and watching them wrap small handmade seaweed soaps. I am accompanied by a translator named Rossie who assists in asking questions. Not understanding their mother tongue (KiSwahili) means I am more focused on their facial expressions and body gestures - and this tells a story in itself. Rossie confirms my observations - the women seem to feel like they are a part of something bigger. The ocean has become a haven. In the shallows, they feel at ease discussing their everyday lives, current affairs and family problems. It is a space where they come together in trust, sharing ideas and supporting each other. Away from the shores, they help with weddings and funerals and sometimes even food. They turn to each other for financial support, and automatically accept family members into their nuclear farming teams. "With one person, you can only do from here to there," one woman humbly shares, gesturing with her hands. "But with many, you can do more."

Later that week, I pay a visit to the oldest (retired) seaweed farmer at her home in the village. I arrive with a big, juicy pineapple and am offered the only bench in the house. Though my host is clearly senior, she settles herself on the floor. Her name is Mwanamtumwa Imani Ally and while she was never given a birth certificate, she believes she is in her nineties. She was introduced to seaweed farming by her neighbour more than 30 years ago, a time when seaweed was in such abundance that every morning it was available in the shallow water - staked farms were not needed back then. She worked independently for a decade before joining the Seaweed Co. (now called Mwani Zanzibar, an international skincare company). She recalls the terrible outbreak of "ice-ice disease", which most notably affected crops in the Noughties. Higher ocean temperatures, increased salinity and intense sunlight caused by climate change, led to the bleaching of seaweed, a declining yield and the blistering of many farmers' arms.

We sit on the dimly lit porch, illuminated by the light shining from inside her house. I can just about make out her face. She is small with weathered features but remarkably animated for a woman so near to a century in age. During my visit, a phone rings noisily. I hear a party picking up down the road and the trade winds are blowing. I hope that my dictaphone is recording her full story.

There is hardship here. Women go through a lot to raise their families. They come from a background where, if they are not educated and don't hold a job, they are very much at the mercy of their husbands. If a marriage is failing, women are less inclined to leave because they have no financial options. But Mwanamtumwa, who has found financial security with Mwani Zanzibar, fondly recalls a time when she had to loan her husband money to feed the family. When he returned it, he said: "This is for you, my wife."

Towards the end of our nearly two-hour conversation, Mwanamtumwa is propping herself up against a wall pasted with flapping flyers promoting the recent local elections. It is only at this point that her age starts to show, I can see she is tired. The next day, when she pops up behind me with a hug, I am reminded how small the village is. We are friends now.

The proceeds from seaweed sales are barely enough to sustain these farmers and their families, even when working independently. This compelled Klaartje Schade, co-founder of Mwani Zanzibar, to establish Mwani's range of exceptional products that are kind on the skin and the planet, also paying her employees six times the average income of a regular seaweed farmer.

"Seaweed farming accounts for only 25 per cent of the work here at Mwani Zanzibar. We are the only company that actually processes the seaweed before it leaves our shores, and when you think that more than 15,000 tons are exported each year..." says Klaartje.

According to the Zanzibar Ministry of Trade, Industry and Marketing, the country's seaweed-farming industry comprises 23,000 workers (the majority being women operating on small-scale farms) who contribute to 90 per cent of the island's marine export products. The island has also become the third-largest exporter of seaweed in the world. In Paje's shallow waters, women have not only found work but, more importantly, independence.

Today Mwanamtumwa, approaching her hundredth birthday, still visits the shoreline from time to time to show her granddaughters the ropes. Watching them farm seaweed like she used to decades ago gives her a wonderful sense of pride. The world around us may be in constant flux, but this sisterhood bonded by seaweed is something that won't be changing any time soon.