Farming Seaweed Around The World | A Visual Essay

In a world where a growing population and a changing climate is putting pressure on both our land and marine resources, seaweed offers a potential solution.

Seaweed is cheap to produce, nutrient-dense, and can play a restorative role in damaged marine ecosystems. Beyond food, seaweed also has a number of potential uses that make it one of the most versatile natural products available. It can be used as fertilisers, biofuels, and even alternatives to plastic.

But it’s not just these global benefits we can see through consuming more seaweed. At a local level, seaweed farming also has enormous potential to positively impact coastal communities, particularly those in vulnerable and geographically isolated areas.¹ With low startup costs, and requiring only a few weeks until seaweed is ready for harvest, it can help these smaller communities to improve their food security and economic resilience. 

This low barrier to entry into the industry also means the sector is dominated by smallholder farmers; over six million, across 48 countries.2 One FAO study reveals how these communities can be transformed by seaweed farming, with increased incomes allowing children to attend school, have enhanced diets, and improved standards of living while also reducing incentives for overfishing.³ For women in these areas in particular, seaweed farming has been seen to be incredibly empowering, by providing them with an income source and an increased level of independence. Around the world, this has been seen to lead to a profound shift in gender equality in traditionally patriarchal communities.¹

Sadly, it’s not all good news; rising sea temperatures due to climate change make farmed seaweed vulnerable to pests and disease, a serious problem when the industry relies on just a few species. In Zanzibar, for example, the maximum recorded temperature of inshore coastal waters has risen from 31℃ in 1990 to 38℃ in 2020. The value of the Tanzanian seaweed crop declined from US$4.3 million in 2015 to US$2.4 million between 2016 and 2020.² Moving production to deeper, cooler water can be a solution, but it can negatively impact female farmers in some smaller communities, who may not have the resources to purchase a boat. While seaweed farming does have many economic benefits, coastal communities are still some of the poorest around the world, and it's imperative that policy makers and governments seek solutions to support seaweed farmers in finding solutions, such as diversifying the species that they are growing to ones which are better adapted to these rising temperatures.
 

Bangladesh

In Bangladesh, seaweed farming is seen as a key component to achieving several targets of United Nations sustainable development goals (SDGs) and the blue economic development in Bangladesh. As of 2021, around 300 households were farming seaweed along the southeast coast.⁴ This area of Bangladesh is relatively low-income compared to the rest of the country, and seaweed farming has great potential to uplift these marginalised coastal communities.⁵

Morium and Anowara, at work in a seaweed farm. April 2022, Nazirhat, Bangladesh (Photos by FAO/GMB Akash).

Left: Forida, shows a hank of dried seaweed. Right: Forida and Anowara, at work on the drying of seaweed. April 2022, Nazirhat, Bangladesh (Photos by FAO/GMB Akash)

Indonesia

While seaweed production in Indonesia is focused on community-based farming activities, over the last decades, government-led initiatives to promote seaweed farming have led to huge growth of the industry; increasing by more than ten times between 2005 and 2014.⁶ A high number of seaweed farms are female-led, which is well supported by the wider community, including village counsellors and youths community leaders.⁶

A woman carries part of her daily harvest of seaweed in to land, Lembongan Bay, Indonesia. (Photo by Jonas Gratzer/LightRocket via Getty Images)

Collecting seaweed, Nusa Penida, Bali, Indonesia

Seaweed farming in Nusa Lembongan island, close to Bali, Indonesia

Tanzania

In Tanzania, seaweed farming significantly contributes to the economy, mostly in the Zanzibar Archipelago. Over 80% of seaweed growers here are women, and the income from this has significantly empowered women in this community.¹ With more financial independence for women in this region, it has led to added funds for their children's education, medical care, public housing, clothing improvements, and family food security.¹ 

However, with a reliance on growing one variety of seaweed (Eucheuma cottonii), rising sea temperatures are impacting this industry in Zanzibar. This species grows best in water temperatures of 25℃ to 30℃, but with temperatures now rising to 38℃, the seaweed grows less and is more susceptible to disease.²

In the shallow waters off the east coast of Zanzibar, seaweed is farmed by tying small bunches of seaweed to pieces of string, which are secured to the seabed with wooden stakes. After 6 weeks, it is ready for harvest, when it is taken ashore and dried in the sun before being exported. (Photos by Kiki Streitberger)

China

Seaweed production in China accounts for 58% of the world’s farmed seaweed.⁷ Kelp (Saccharina (Laminaria) Japonica) is the key species, cultivated predominantly in the Fujian and Shandong provinces, which contribute 42% and 32% of the total annual cultivated seaweed in the country. With an annual production of nearly 1.5 million tons (dried weight) — or 68% of the total seaweed production in China — this reliance on a single species leaves producers vulnerable to climate change as sea temperatures rise.⁸

Top: A farmer dries kelp in Rongcheng, Shandong Province of China, May 2023. (Photo by Liu Guoxing/VCG via Getty Images) Left: Farmers work at a seaweed farm in Xiapu county, China's Fujian province. Right: Kelp drying, Rongcheng, Shandong Province of China. Rongcheng produces half a million tons of fresh kelp annually, about 44% of China's total. (Photo by Feature China/Future Publishing via Getty Images)

Philippines

Over 200,000 coastal families in the Philippines are employed in the seaweed farming industry, established in the 1970s and accounting for around 40% of the national fisheries output.^1,9 Women are also the beneficiaries of seaweed farming in these communities, giving them the opportunity to generate an income while also providing them with work satisfaction and social recognition.¹

Declining income from traditional fishing has spurred a shift in traditional roles as the community's women turn to seaweed farming as a new source of income. Rather than causing conflict, this has led to greater cooperation and equal decision-making between men and women.¹ Following Typhoon Haiyan's devastating destruction across the Philippines in 2013, women played a key role in reconstructing damaged seaweed farms.¹
 

Algae cultivation in Palawan. Cuttings of algae are attached on submerged ropes, held taut between stakes, following the main current. (Photo by Patrick Aventurier/Getty Images)

Gloria Mandawe (56) seaweed farmer, Tamiao, Bantayan Island, The Philippines. Gloria starts work at 5 am to remove the algae from the seaweed by hand so that it will grow faster. Seaweed is fast growing and can be harvested in 1-2 months. The seaweed is then dried and sold to local buyers and a commercial processing plant in Cebu, where it is turned into powder; a high value product used by many industries including cosmetics and food. Before Typhoon Haiyan, Bantayan Island was the largest seaweed producer in Cebu province. (Photo by Tessa Bunney/In Pictures Ltd./Corbis via Getty Images)

Japan

In Japan, seaweed has been eaten for centuries, with the most important seaweed species being Nori, Kombu, and Wakame. Today, farms in Japan fulfill 90% of the global demand for these types of seaweed.

Through the 1940s however, Nori farming in Japan almost collapsed, due to a series of typhoons and pollution in the water which led to the devastation of the seaweed beds. At the time, the life-cycle of the seaweed was not understood, so farmers lost their livelihoods, unable to grow new plants.

It was a British scientist, Kathleen Drew-Baker, who figured it out while studying laver, the Welsh equivalent to Nori. She published a paper in 1949 detailing her understanding of the development of laver. This was picked up by Japanese scientists, who were able to use the research to develop methods to artificially grow nori, and revive the industry.

In Japan, Kathleen Drew-Baker is known as the “Mother of the Sea”, and there is a festival held in the city of Uto each April in her honour.

Farming rafts and fishing boats of Uwakai in Japan. (Photo by paprikaworks/Getty)

Chad

Algae is also grown and consumed by communities inland. One example is in Central Africa, where spirulina, a blue-green microalgae related to seaweed, grows abundantly in Lake Chad. It is collected, dried, and made into a nutritious, protein-rich sauce known as dihé, which has been consumed by the Kanembu people of Chad for centuries. This task, traditionally performed only by the Kanembu women, has now become a source of much-need jobs and income, after the FAO launched a project in 2007 to support the women in harvesting more efficiently and prepare the product to export to the international market as a health supplement.¹⁰

In Central Africa, Spirulina grows abundantly in Lake Chad and is collected, dried, and made into a sauce which is widely consumed by the Kanembu people of Chad. (Photo by FAO/Marzio Marzot)