Seaweed Farmers of Zanzibar

Have you eaten seaweed recently?

Seaweed is cultivated, harvested, and consumed all over the world in an infinite number of ways. Perhaps you’re a fan of sushi, seaweed salad, or those little dried sheets of crunchy, seasoned seaweed in a ridiculous amount of disposable plastic packaging? But regardless of your personal feelings about eating seaweed, the answer to that first question is almost definitely yes.

Carrageenan is a chemical naturally derived from red seaweed, and no it will not give you cancer. Essential to products like oat milk, ice cream, soap, and lipstick, carrageenan is a thickening agent found in many processed goods. You can also just eat the algae right out of the sea (though people here don’t really do this, and I didn’t find it to be very tasty).

A farmer and her crop of seaweed in Pemba Island, Zanzibar

So where am I, exactly?

As I write this, I’m sitting on the wooden deck of a lodge on the south coast of Pemba, an island in the Zanzibar Archipelago. Zanzibar is part of the United Republic of Tanzania, situated in the Indian Ocean off the East African coast. Despite this geopolitical distinction, Zanzibar is much more like other parts of the Swahili Coast than the bulk of mainland Tanzania. For centuries, Zanzibar was at the center of trade between East Africa, the Middle East, and the Indian Subcontinent. Modern Swahili culture is a product of this diverse mix of Bantu and international influences, with a shared language (Swahili) and a shared religion (Islam). In the medieval period, the Swahili coast was a web of rich city-states ruled by sultans. Many of these featured beautiful “stone towns” like Zanzibar City and Lamu, Kenya, constructed of gray coral stone and mortar.

Zanzibar was also an important port along the East African slave trade route, where captured Bantu people from the mainland were held and sold, forced into ships headed for Asia, the Middle East, and the Americas. Even after the trade was banned in 1807, it continued in secret for decades. Perhaps the most infamous of these slave traders was Tippu Tip, an Afro-Omani slave and ivory merchant from Zanzibar. His mansion still stands in Stone Town (the historic, winding downtown of Zanzibar City), marked by an informational plaque and a brief biography. My host mother in Kigoma took me to see his other house, 779 miles away in Ujiji, Western Tanzania. Slave caravans from the Great Lakes region of the interior were forced to walk these hundreds of miles to the coast, often over the course of several years. Unmarked by any plaque or commemoration, Tipu Tipp’s Ujiji house is now a family home.

Zanzibar was under Portuguese control (16th-17th centuries), then fell to the Sultanate of Oman in 1698. It became a British protectorate in 1890, preserving the Omani Sultan of Zanzibar. The islands gained independence from Britain in 1963 as a constitutional monarchy under the Sultan. This government was overthrown in 1964 in the Zanzibar Revolution, which also triggered the massacre of thousands of ethnic Indian and Arab citizens. It merged with mainland Tanganyika in 1964 to form the United Republic of Tanzania, a union that has held up but not without tension between the two regions.

This is a disrespectfully brief overview of Zanzibar’s long and complicated history, but I am not an expert and am mindful of the ostensibly seaweed-focused nature of this post.

Zanzibar Today

Zanzibar is made up of three large islands: Unguja, Pemba, and Mafia. I haven’t been to Mafia, but I have now visited seaweed farms on the other two. Unguja is famous for Stone Town, spice farms, and sugar-white sand beaches that draw flocks of tourists throughout the year. As tourism has grown on the island in recent decades, many would-be seaweed farmers now work in restaurants and hotels. This, combined with warming waters and more environmental disturbance in the waters around Unguja means that the island is not as productive (seaweed-wise, that is) as its northern sibling, Pemba.

Sunset in Pemba

I took the ferry from Unguja to Pemba, a six hour-long cruise across the Indian Ocean along

with about a dozen cargo trucks, many cages of chickens, and countless passengers stretched out on mats or snacking on buns and spiced tea. My first-class ticket afforded me a spot in this special bay with a snack bar and large TV screens playing Indian reality TV dubbed in Swahili. The snack bar was great, but it was so violently air conditioned that I spent the entire journey walking between the enclosed bay and the sunny deck to regulate my body temperature like some sort of lizard.

Tourists largely ignore Pemba because instead of vast stretches of powdery beach, it has a complex coastline of lush mangroves. I saw a HUGE bat from the porch a few days ago, and thus found out that the Pemba flying fox lives here with a wingspan over five feet. Five feet!!! Less charming are the spiders as big as my hand that casually set up shop between people’s houses. Nobody seems to mind them, but I must concentrate very hard to keep them off my mind as I try to fall asleep at night.

So now to the farming: how does it work?

The soil of Zanzibar isn’t suited to large-scale farming like on the mainland, and the sea is the major breadbasket of the archipelago. Dhows (traditional sail boats) fill the lagoons along the coast, and fishers can be seen stalking along the beach at dawn with spears to stick unsuspecting octopi. In the late 1980s, the C-weed Corporation began to introduce red seaweed farming to communities along the coast. Similar models for this industry already existed in Indonesia and the Philippines, and the founder and CEO brought in experts from the Philippines to advise the process. Their model is this:

1. C-weed purchases equipment needed for farming (primarily lines, but also stakes, small boats, and rubber boots to protect farmer’s feet from urchin stings)

2. C-weed then provides interested farmers with this equipment for free. They also provide training to the farmers on farming techniques and best practices.

3. Farmers then grow the seaweed, dry it in the sun, and package it in large bags before selling it to C-weed employees at collection points in each village.

4. C-weed then collects the dried seaweed in large warehouses. When orders come in from customers (manufacturers in Europe, Asia, and North America primarily), they ship the product out.

Seaweed turns purple when dried!

Red seaweed (spinosum) farming is dictated by the tides. All the active farming happens during the five or so days of extra-low tide, which occurs about twice per month and exposes the farming beds so they can be accessed by wading in the shallow water. Farmers hammer wooden stakes into the sandy bottom and nylon lines with loops tied on at regular intervals. Seedlings (small pieces of healthy seaweed) are then tucked into each loop, and this seeded line is strung between two stakes so that it is suspended just above the sand. This is important, as seaweed lying directly on the sand can be eaten by sea urchins. The tide then comes in, submerging the algae and leaving it to grow until the next low tide. Each low tide, around a third of the strings are harvested and re-seeded.

My first farm visit in Pemba literally took my breath away. It is enormous, a vast expanse of sandbanks and shallows with neat dark rows of red seaweed against the sandy bottom. They extend as far as I could see in all directions, with little seaweed-filled boats almost disappearing into the distance. The largest farming village, Tumbe, can produce over 1,000 tons every month. Each village may have hundreds of farmers. I say may because it’s a little hard to estimate: C Weed corporation only keeps track of the farm owners (around 1,500 in total), but this has little to do with the total number of farmers. Many farmers work solo, but many others employ workers to help them manage large numbers of lines. This may mean a family that works together, a farmer who employs one or two helpers, or a large farmer who hires many people to manage hundreds of lines. I met one man, Saum, who employs 15 people and produces 2 tons of seaweed each low tide.

Lines of healthy seaweed in Pemba

A seaweed farmer and her crop in Unguja

The majority (~80%) of these farmers are women. Why? The simple answer is that when this opportunity came around a few decades ago, the men were busy fishing. And they largely still are, though an increasing number of men are seeking out farming work as well. Because

of this initial gendered split, some people told me they see seaweed farming as “feminine”, which may perpetuate the continued gender divide. Another reason is the nature of the work itself. Seaweed farming is hard labor during the low tide, but for much of the month there is nothing to do but sit back and wait. Thus, seaweed farming allows women to fully participate and complete all their traditional domestic work.

That being said, the leadership does not match the gender makeup of the farms. The local C Weed Corporation team in Pemba was GREAT – so kind, generous, and genuinely proud of the transformative industry the company has built in their communities. It must be noted however, that they were all men. All the owners of large farming operations I spoke to were men, and those that they employed were mostly women. The C-weed Corporation seems like a great employer, and I talked to many employees who were offered funds and time to pursue educational opportunities that would help them grow their careers. I hope in the future more of these corporate jobs are accessible to women, especially because they make up so much of the actual workforce.

Many of the older women that I spoke to talked about how the industry has changed their villages in the past 30+ years. Before seaweed farming, there just wasn’t any industry that could be scaled in this way on Pemba. The influx of money from seaweed activities allowed people to build new homes, improve existing structures, and pay school fees for their children.

Seaweed drying in the sun

Challenges to Seaweed Farming

The major challenges facing seaweed farmers here are environmental. Red seaweed is a finnicky crop and is easily stressed by temperature changes and depth. If the farms are exposed to the air for more than an hour, they can die. When subjected to stress or physical damage, they develop “ice ice disease” which turns parts of the algae slimy and white. This breaks the algae apart, shedding excess biomass in order (I assume) to have a better shot at preserving the organism.

"Ice Ice" disease

Marine debris, predatory urchins, and competing species of seaweed (notably Brown Ulva)

Abandoned beds with Brown Ulva

can also stunt the growth of red seaweed. When environmental misfortune befalls a plot, the farmer’s only options are to re-set the lines and try again or move to greener pastures - if they can. Available plots can be far away from the weighing station, so small farmers without boats, help, or motors are limited in their mobility. Many women can’t swim (I’m not sure exactly why, but I gather it’s not traditional practice for women to learn), and this makes long boat journeys more dangerous.

The elephant in the room here is climate change, yet again. I didn’t talk with the farmers and C-weed employees about it all that much, because really, what can one do? On a corporate level, C-weed is exploring new areas along the Tanzanian coast to introduce seaweed farming in hopes that geographic heterogeneity will buffer some of the worst impacts. But on a personal level, moving your plot to a more favorable micro-environment is the only tool available. Nobody seemed to know of any research into thermally resilient red seaweed, and there wasn’t much interest. For now, the Pemba farms are the healthiest and most productive in the Indian Ocean. I hope they stay that way for many generations to come.

Up next, I’ll head back to Unguja for a while before flying off to Spain. My dad is making the same epic flight journey that I did to visit Zanzibar, and I can’t wait to see him!!

Thanks for reading,

Grace