Seaweed as a Pillar for Aquaculture and Food Security
By Dr. Abe Woo Sau Pinn, Annette Jaya Ram
May 2025 FEATURE
MALAYSIA IS RANKED ninth on the list over the world’s biggest fish and seafood consumers per capita, way ahead of countries like China, or any neighbouring ASEAN countries. Given Malaysia’s cultural, economic and geographical connections to the sea, our unique position in a mega diverse marine biodiversity area has deeply rooted our diet to seafood. One surely cannot imagine Nasi Lemak without anchovies or Penang’s famous Char Koay Teow without blood cockles. However, I am very sure that this is becoming common as we face challenges of dwindling supply of fish and our ever-growing appetite for seafood.
Malaysia used to be a net exporter of seafood products, but this took a turn in 2013 when we started importing more seafood products than exporting them. Since then, we have been running on a trade deficit on seafood, which in 2022 amounted to (-)RM3.2bil.[1] Past issues in Penang Monthly have already highlighted several strategies on improving the sector through the lens of sustainability in capture—fisheries, restorative aquaculture, supply chain management and ecosystem protection;[2][3][4][5] therefore, I shall not repeat them here.
Consider Sea Vegetation
I have tried to think about traditional seafood dishes made from seaweed, and I have come to realise that seaweed is not really eaten much as it is part of our diet. Apart from the delicacies in Sabah, the only other traditional dish that is made from seaweed can be found in Kelantan, known as kerabu sare (kerabu sarang). It is made with a type of red algae from the genus Gracilaria typically found in the shallow coastal area of Peninsular Malaysia. Although 44% of Malaysia’s aquaculture output in terms of tonnage is seaweed,[6] it doesn’t seem like farmed seaweed made it in our dishes—but let’s look at the edible weeds from the sea.
1) BROWN SEAWEEDS (Phaeophyceae)
Brown seaweeds were once the leading group in seaweed aquaculture. Laminaria japonica, known as “kombu”, is among the most commonly cultivated, especially in East Asia. It is widely used as food, particularly in soups and also processed for compounds like alginate, mannitol and iodine. Another significant species is Undaria pinnatifida or “wakame”, native to the cold, temperate coasts of the northwest Pacific. It is popularly used in dishes like Chuka Wakame, especially in Japan and Korea. China, Japan and Korea remain the largest producers of brown seaweeds, reflecting a strong cultural and commercial history.
2) RED SEAWEEDS (Rhodophyta)
Red seaweeds now dominate global aquaculture production due to increased cultivation in tropical regions. This group includes species such as Kappaphycus, Eucheuma and Gracilaria, which are primarily grown for hydrocolloid production, specifically carrageenan and agar. These substances are widely used in the food industry as thickening and stabilising agents. The Philippines and Indonesia are key players in the cultivation of red seaweeds, which has led to a shift away from traditional brown seaweed dominance. Red seaweeds are also valued for their high yield and ease of cultivation in warmer climates.
3) GREEN SEAWEEDS (Chlorophyta)
Although green seaweed production has declined since the 1990s, several species still play important roles in food and aquaculture. The Ulva species, commonly referred to as sea lettuce, are used in dried food products and as animal feed. They are particularly suited for integrated aquaculture systems due to their high growth rates, nutrient absorption capabilities and simple life cycles. In South Africa, for example, Ulva is farmed to support abalone feed. Another notable species is Caulerpa lentillifera, or sea grapes. These are a high-value delicacies in places like Okinawa and the Philippines. These green seaweeds are often sold fresh and fetch premium market prices. These tiny grape-like bulbs is also promoted as green or vegan caviar for those who choose not to consume fish roe or true caviar.
Socio-Economic Impacts of Seaweed Farming
Seaweed farming generates wide-ranging socio-economic benefits. It provides employment opportunities, especially in coastal areas with limited economic options. The work spans cultivation, harvesting, processing and marketing, helping to develop local industries. In countries like Tanzania, seaweed farming has become a major economic driver for women, who represent around 90% of the farming workforce. It also supports income diversification, reducing reliance on fishing or other seasonal activities.[7]
Cultural impacts are more nuanced. Seaweed farming can support the preservation of traditional practices when aligned with local customs, but may also disrupt existing land use and routines. Successful integration depends on active community engagement, cultural sensitivity and education. Conducting cultural impact assessments and involving locals in decision-making helps foster ownership and long-term support. Additionally, the industry encourages innovation and entrepreneurship, for example, using seaweed for biodegradable packaging;[8] while helping to develop new local markets and attract investment.
Environmental Impacts
When done sustainably, seaweed farming has low negative impacts and, in fact, brings ecological benefits. Seaweeds absorb excess nutrients from the water, improving water quality and helping prevent eutrophication. They also contribute to marine biodiversity when farms are thoughtfully located.
However, there are potential downsides. Introducing non-native seaweed species can pose invasive threats to local ecosystems. While frameworks exist, farmer awareness and compliance remain inconsistent. Additionally, seaweed farms can cause shading of the seabed, which may affect photosynthetic organisms. While small to medium farms usually have minimal impact, cumulative shading from large-scale operations could alter planktonic and benthic communities.
Chemical use is typically limited in seaweed farming but still poses risks if fertilisers or pesticides are involved. Sustainable practices and monitoring are essential to prevent environmental contamination and ensure long-term viability.
Versatility and Integration
Seaweeds are incredibly versatile and are used in a wide range of products, from food and cosmetics to packaging and pharmaceuticals. Their multifunctionality supports a circular economy and adds value to marine-based industries. One of the most sustainable models is Integrated Multi-Trophic Aquaculture (IMTA), where seaweeds are cultivated alongside species like fish or shellfish. In these systems, seaweeds absorb excess nutrients from animal waste, improving water quality and enhancing overall system sustainability. This approach not only reduces environmental impacts but also increases the efficiency and profitability of aquaculture operations.
Seaweeds Aiding Food Security
Aquaculture (which includes seaweed cultivation) is a potentially lucrative business when integrated well with technology like Internet of Things (IoT), big data analytics and automation. This can be seen in Japan where advanced indoor and controlled environment farming of salmon done with high precision, aided by technology, has generated high returns to the company.[9]
During a visit to a high-tech farm in Chiba, Japan, I saw how it produces 30 tonnes of salmon per year, and has managed with almost no wastewater discharge. This certainly does not look like a traditional outdoor pond, but rather, a clean one equipped with technologically advanced instrumentations and sensors. This should be the future of how we grow seaweeds as well. Think of it as vertical farms with multiple colourful LED lights to stimulate growth of vegetables like kale andarugula. Seaweed farming in Malaysia has started to employ technologies with sensors and LED lighting to efficiently produce cleaner, tastier and organic seaweed such as sea grapes. One example is done in Kuala Selangor in cooperation with Centre for Marine and Coastal Studies (CEMACS). Now, this farm has become a major supplier of sea grapes in the Klang Valley!
If we want to see change in this industry, we need to deal with the dwindling number and the aging workforce in fisheries and aquaculture. The number of licensed fishermen saw a constant reduction a 1.6% year-on-year basis on average from 1998-2023. This is coupled with a surge of foreign workers from Thailand, Indonesia and Vietnam working as fishermen in Malaysia. It is a no-brainer that our youths have shunned jobs that are deemed unappealing, outdated or lacking in career prospects. The image imprinted of a wooden sampan, back-breaking pulling of fishing nets and long hours under harsh weather conditions painted the industry as “low-status” and “poor”. It is not surprising that fisheries and aquaculture are laggard industries with limited and low percentage of innovation and knowledge advancement.[10]
Changing the narrative of fisheries and aquaculture sector is of utmost important, alongside efforts in managing fish stocks, enforcing sustainable practices or even ecosystem restoration. To attract young talents to a career in aquaculture and fisheries, it is imperative to integrate technology and modernise the industry. A concerted effort by multiple stakeholders, especially education institutions, is crucial. As for myself, would I recommend any of my younger family members (or my students in the university) to think of a career in fisheries and aquaculture?
Yes, definitely!
Footnotes
[1] 2022 Annual Fisheries Statistic, Department of Fisheries
[2] Seafood – Now and Forever, Penang Monthly, December 2018
[3] A Sustainable Seafood Supply Chain Requires Responsible Practices at Every Link, Penang Monthly, September 2019
[4] Aquaculture: The Good, the Bad and the Restorative, Penang Monthly, January 2022
[5] Caught in the net The Malaysian seafood industry waits in vain, Penang Monthly, March 2010
[6] 2023 Annual Fisheries Statistic, Department of Fisheries
[8] https://steemit.com/steemhunt/@dwiitavita/evoware-biodegradable-packaging-is-made-from-seaweed
[9] https://frd-j.com/en/home-en
[10] Blue Economy Position Paper, Academy of Sciences Malaysia
Dr. Abe Woo Sau Pinn
studies the biodiversity of marine invertebrates and their systematics. His research interests include ecology, diversity, systematics and taxonomy of echinoderms.
Annette Jaya Ram
Dr. Annette Jaya Ram is a lecturer and deputy director of the Centre for Marine and Coastal Studies, USM. She is studying mariculture of mud crabs; currently working on best ways to culture them to reduce dependence on harvesting mud crabs from the wild.
