Climate change threatens small seaweed farmers in the Philippines

Commercial seaweed farming began in the Philippines in the 1970s and has grown to be one of the country’s most significant aquaculture enterprises, supporting more than 200,000 coastal families.

A seaweed farmer from Sitio Cabgan in Barangay Loyola, Hinatuan, Surigao del Sur, Philippines. Image: Oxfam International, CC BY-SA 3.0, via Flickr.

“Seaweeds are important to me because they give me joy when we plant them,” says Melinda Gimotea, as she crouches down among the pile of seaweed seedlings under her stilt house on the southwestern coast of the Philippines’ Palawan province. Facing the teal blue sea on a fine July morning, the 55-year-old ties the olive-green plant cuttings to ropes with floaters, each spanning 25 meters (82 feet).

In her village, Balintang, seaweed farming builds a sense of community and strengthens family ties, as it gives opportunities for community members to connect with each other, Gimotea says:  “It’s a time when we get a chance to bond with my neighbours, with my family.”

Early the next morning, she hops with her husband on a 2-meter-long outrigger boat and paddle a few meters offshore until she reaches her 2,500-square-meter (0.62-acre) farm. There, they drop the prepared seaweed lines and leave them until they’re ready for harvest in 45 days.

This has been her family’s routine for three decades. Earning between 25,000 to 30,000 pesos ($445 to $534) every production cycle, the mother of five says seaweed farming has allowed her family to put two children through university and afford relative luxuries like refrigerators and a television. “It is also where we get everything we need at home, and we’re also able to buy appliances that we otherwise couldn’t afford if not for seaweeds,” she says.

Our roadmap is addressing the deteriorating quality of seaweed propagules, one is through strengthening our seaweed culture with the vision of producing climate resilient, fast growing and disease-resistant propagules.

Demosthenes Togonon, seaweed development program national coordinator, Bureau of Fisheries and Aquatic Resources

In the Philippines, over 200,000 coastal families like Gimotea’s engage in commercial seaweed farming, which was first introduced in the country in the early 1970s. Five decades later, the Philippines emerged as the world’s fourth largest producer of aquatic plants, including seaweed. In 2020, the country produced 1.48 million tonnes (1.63 million tons) of aquatic plants, or 4.56 per cent of the total world production of 32.4 million tonnes (35.7 million tons).

The Philippines’ seaweeds are exported to the United States, China, Spain, Russia and Belgium, where they are prized for carrageenan, a gelatin-like additive used as a thickening agent and stabiliser for many food and cosmetic products.

In many coastal communities, seaweed farming also has proven its value as a way to help address poverty and environmental issues, such as illegal, unreported and unregulated fishing (IUUF), and degradation of quality of habitat for endangered marine life. However, climate change that triggers seaweed disease and pest problems is becoming a threat to this industry, leaving Gimotea and many others worried about their families’ futures.

Conservation enterprise

In Gimotea’s village, women organised themselves into the Cherish Fisherfolk Association. When the group was registered with the Philippines’ labour and employment department in 2018, it opened opportunities for scaling up its seaweed production. These included access to production loans, as well as grants to build land-based and floating seaweed dryers with support from USAID Protect Wildlife and the nonprofit Lutheran World Relief and Ecumenical Church Loan Fund.

Such facilities cut short the seaweed drying period from almost a week to two to three days, allowing farmers to increase their production. “By renting out these dryers, as well as our motorised boat, to members and non-members who engage in seaweed farming, we earn additional income,” says association president Mardy Montaño.

Recognizing seaweed production as one of the Philippines’ most important aquaculture commodities, the government also provides both material and technical support to communities like Balintang. “To intensify seaweed production, we conduct capacity-building training with communities and provide them with planting materials, such as propagules, straws and ropes,” says Palawan provincial agriculturist Romeo Cabungcal.

Locally, Cherish is gaining renown for its seaweed noodles and chips. While waiting for their seaweed to mature, women are most often seen at the association’s centre, enjoying each other’s stories as they manually produce these snacks.

“As more towns are reached by our products, we’re glad that locals are patronizing these delicious and healthy foods,” says Montaño, whose group was trained by the provincial government in seaweed processing.

According to the FAO, seaweeds are excellent sources of micronutrients such as iron and calcium, as well as vitamins A, C and B-12. Sea plants are also the only non-fish source of natural omega-3 long-chain fatty acids.

With the government’s goal to improve seaweed post-harvest in the country, Cabungcal says they connected the association with the World Bank-assisted  Philippine Rural Development Project to gain access to grants to scale up the seaweed noodles and chips production and become a provincial seaweed consolidator. “If their proposed project prospers, they will greatly benefit in terms of infrastructure and machinery for the seaweed processing,” he says.

Local officials say that seaweed farming has not only helped uplift the socio-economic condition of families in this village, it has also helped in the recovery of its coastal waters from the threats of illegal, unreported and unregulated fishing.

Since the association’s inception, members have been key partners of the municipality’s Bantay Dagat, or a volunteer sea patrol unit, voluntarily monitoring their coastal waters for IUU fishing, explains Pacita Bravo, an agricultural coordinator with the municipal government.

“Seaweed farmers are out at sea almost every day to check on their farms, and their presence there has helped in reducing illegal fishing because they report to authorities whenever they chance upon violators,” Bravo says. “So that discourages illegal fishers, and through time they have also shifted to seaweed farming.”

Cherish also advocates for a total ban on the use of aquaculture fertilisers that contain chemicals with potential adverse impacts on human and marine life health. This is being emphasised among members because the seaweed farms end up serving as grazing areas for economically important herbivore fishes and molluscs, and endangered species like Green sea turtle (Chelonia mydas) and Dugong (Dugong dugon), says Montaño.

Climate-induced disease, pest

For years, Gimotea and other women engaging in seaweed farming in her village enjoyed productive seaweed harvests. But since 2021, they have started feeling the effects of changes in local weather patterns and environmental conditions due to climate change.

In late 2021, Typhoon Rai wiped out their seaweed farms. Just when they began recovering from the devastation and restarted the planting, a warmer than usual dry season came, triggering diseases and pests.

“As the climate continues to change, it’s always sunny here, the heat is extreme, the wind blows intermittently, and the ocean warms as well,” says Gimotea, as she sits at the far end of her outrigger boat filled with seaweed lines ready for planting. “When the heat is extreme, it can cause seaweed diseases.”

She bends and dips her one hand in the sea to grab a seaweed line in her neighbor’s farm, which has been afflicted by ice-ice disease or the whitening of seaweed branches. The disease, which is caused by a combination of marine fungi and bacteria, causes infected seaweed to disintegrate and decay.

Joseph Faisan Jr., a seaweed researcher with the Southeast Asian Fisheries Development Center’s (SEAFDEC) Aquaculture Department, explains that “extreme weather events brought about by climate change make seaweed farms vulnerable to fluctuations in environmental conditions, especially in coastal areas where high temperature or low salinity could be observed the most.”

This is why farmers should consider transferring farm sites to deeper areas where the environmental conditions are stable, he says.

When seaweeds are exposed to stressful conditions, seaweed health is compromised, making them susceptible to disease and pest problems, Faisan explains. Ice-ice disease, as well as epiphytic pests (algae that penetrate and damage seaweeds’ inner layers) are the common health problems observed in seaweed farms in the Philippines, he says.

“Based on the recent survey conducted, these problems are already prevalent in the major seaweed-producing areas in the country,” adds Faisan, lead author of a 2021 study on seaweed diseases in the PhilippinesIn times of outbreaks, he says biomass yields are reduced and the carrageenan quality is compromised.

It’s concerning, Faisan says, because it can affect the income of approximately 1 million farmers and workers connected to the seaweed industry, a significant Philippine economy contributor. In 2020, the government reported that seaweed was the country’s top aquaculture commodity in terms of volume at 1.5 million tonnes (1.65 million tons), and second in export value amounting to $250 million.

The presence of these diseases in seaweed farms could also, potentially, increase the vulnerability of patches of wild seaweed, which are important marine habitats. “I have yet to read a scientific paper on the horizontal transfer of disease or pest from cultivated seaweeds to the wild or native seaweeds. However, I think the said transfer is highly probable,” says Faisan.

For farmers, monitoring seaweeds is a key activity in order to reduce losses. “They fall into the sea if we fail to monitor them often,” Gimotea says. “Because ice-ice disease spreads fast, if you spot them today in your farm, you should harvest them the next day to prevent them from getting widespread.”

Since outbreaks have become more frequent, she says her family’s income has halved, an economic shock worsened by rising inflation in the country. “Our fear, if it’s always like this, that the climate changes, we would go into poverty because we won’t be able to sell many seaweeds,” she says. “That’s why we appeal for help to address this,” she says.

Interventions and challenges

The Bureau of Fisheries and Aquatic Resources (BFAR) developed the Philippine Seaweed Industry Roadmap 2022-2026 to address industry issues, including the prevalence of ice-ice disease and epiphytic pests, and regain the country’s international seaweed market position.

“The BFAR, through our roadmap, is addressing the deteriorating quality of seaweed propagules, one is [through] strengthening our seaweed culture with the vision of producing climate resilient, fast growing and disease-resistant propagules,” says Demosthenes Togonon, seaweed development program national coordinator. “So we’re on our way, slowly but surely, we’re making a little progress on that.”

Currently, the BFAR’s National Seaweed Technology Development Center produces what it describes as  “healthy and disease-resistant seaweed propagules,” by cutting and propagating stems from healthy seaweeds. These propagules are distributed to farmers free of charge.

However, the centre aims to go further, utilizing genetic engineering technologies to produce strains of seaweed that are more resistant to pathogens and environmental stresses. This, Togonon says, remains a long-shot initiative that would require outside support, since the country only has seven small labs. “[We] have the technology but the big challenge for us is in the operation and management side, because if we’re envisioning to produce huge quantities, we need a commercial facility.”

This potential solution has also raised concerns among activists. “If ever the BFAR employs genetic engineering in strain development, the potential repercussions of genetically modified seaweeds should be studied first because GMOs have no scientific consensus on safety,” warns Greenpeace Southeast Asia campaigner Wilhelmina Pelegrina. This could also have economic implications as the Philippines primarily exports seaweeds to Europe, where many countries have imposed a ban on GM crops. “So it defeats the competitiveness and purpose of seaweed production,” Pelegrina adds.

Despite the uncertainties brought about by climate change, and the lack of consensus on how to deal with these external shocks, seaweed farmers like Gimotea remain hopeful. “If I’m paddling to the sea to drop the seaweeds, I’m happy seeing the seaweeds; they’re like people who are happy once they reach the sea. I talk to them, I tell them to grow well, hoping they would not catch any diseases, because it’s through our income from seaweed farming we’re able to get our daily needs,” she says.

This story was published with permission from

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