Farmed Seaweed

Overview

98%

of the world's seaweed production is farmed, preserving our ocean and coastal ecosystems

Seaweed is easy to grow, versatile, and beneficial to ocean ecosystems. Farming seaweed is an efficient way to produce highly nutritious food for a growing population. Unlike terrestrial crops, seaweed doesn’t require fertilizer, pesticides, freshwater, or land, and it grows rapidly—some marine algae can be ready to harvest in as little as six weeks. It acts as an underwater forest that absorbs carbon, nitrogen, and phosphorus, making it a valuable tool to fight climate change and a water purifier, while also creating new habitat for a diversity of marine life.

Seaweed production has grown to over 35 million tons, more than doubling in the last decade. Packing a nutritional punch of minerals, amino acids, and iodine, it is used in both human and animal food, and can be found in a variety of medicine and beauty products, biofuels, and packaging.

China, Indonesia, and the Philippines lead the world in volume of production, but seaweed farming can be found in many countries, including Tanzania, Sweden, Chile, and the United States. Most farms operate in shallow coastal waters, competing for space with fishers and other uses. Technology to farm sustainably in harsher ocean conditions is newly developing. WWF is working to grow this industry to bring the benefits of seaweed farming for nature, people, and climate to scale.

Why seaweed is a jack-of-all-trades in the fight against the climate crisis

On the surface, brown kelp might not look like the most exciting plant. But when it comes to tackling the climate crisis, this large algae—one of around 12,000 species of seaweed worldwide—has superpowers. It can store harmful greenhouse gases, reduce the carbon footprint of the global food system, help coastal communities adapt to climate impacts, and even be made into a climate-friendly alternative to plastic!

Kelp on a line at seaweed farm

Why It Matters

  • More Sustainable Food Source

    Seaweed farming doesn’t require fresh water, pesticides, or fertilizer. As the world looks to meet a growing demand for healthy food, the low environmental footprint of farmed seaweed makes it an important ingredient of the future food supply.

  • Combating the Climate Crisis

    As it grows, seaweed absorbs carbon from the water around it. When used in animal feed, some seaweeds have helped to reduce methane produced by livestock. If seaweed can be farmed at scale, there is the potential for meaningful local impacts.

  • Supporting Community Development

    Overfishing often leaves coastal communities struggling to support their families. Seaweed farming is one opportunity for local communities to pursue an economic alternative to improve their livelihood.

Impacts

Man holding carbon rod

Michael Chambers, a professor at the Center for Ocean Renewable Energy at the University of New Hampshire, holds a horizontal carbon fiber composite grow line at the Judd Gregg research center in Newcastle. The newly designed rods are being tested to break rather than entangle sea animals.

Invasive Species

In some cases, seaweed species have turned invasive when grown outside their natural range, overgrowing coral reefs, and throwing off the balance of the local ecosystem. WWF supports the production of local seaweed species wherever farming activities are taking place and encourages the development of new native species as seaweed farming expands worldwide.

Marine Mammal Entanglement

While occurrence is rare, entanglement of protected species with seaweed farm rope structures is a potential concern in both near-shore and offshore. Entanglement is unlikely but could have negative impacts on species in surrounding waters. WWF is partnering with researchers to develop a low-cost sensor that could be deployed on farms to rapidly alert a farmer to an entanglement event, increasing the likelihood of survival. Smart siting of farms and keeping ropes taut are best practices for any seaweed farm. There have been no credible documented marine entanglements in 40 years.

Changes to existing ecosystems

Seaweed farms can reduce the amount of light that reaches the seafloor beneath them and could make it challenging for other photosynthetic organisms like seagrass to grow. For a farm to receive a permit, it must be located away from seagrass beds and marine mammal locations like seal haul-outs. Every farm goes through a public and governmental review to ensure that surrounding ecosystems will not be harmed.

What WWF Is Doing

People touch and examining material

Scaling Production

To maximize climate and environmental benefits, seaweed farming will need to be scaled. Moving farms to exposed environments, away from other ocean users, opens the door for growth but also requires innovation. WWF is coordinating a global effort to create public acceptance to operate farms in the ocean, working to develop innovative technologies, and supporting entrepreneurs in advancing this field. WWF is also partnering with researchers to measure the ecosystem benefits of seaweed farms by examining their uptake of CO2, nitrogen, phosphorus, and their contribution to long-term carbon storage to combat climate change.

Boats on water at sunset

Driving New Markets

WWF is working with companies to create incentives to scale farms. Livestock feed is a market with high potential to help the industry scale. Substituting 1% of current animal feed with farmed seaweed could increase demand by 16 times while improving animal health and potentially reducing methane emissions. All types of seaweeds contain valuable proteins that, with the proper technology, can be used in foods and other products. Replacing land-based plant materials with seaweed in packaging alternatives would cut down on plastic pollution in our oceans while doubling demand for seaweed.

Investing for Impact

Seaweed farming provides an opportunity to revolutionize how we think about ocean health, climate mitigation, and food security, but to make a meaningful impact, the industry must scale up in a big way. New technologies, processes, and market innovation are essential to accelerate data gathering, learning, and industry growth. With generous support from partners, WWF aims to advance the technologies and processes needed to meet the conservation and societal challenges facing our planet through impact investments in innovative companies. 

Oceans 2050: The Power of Seaweed

Seaweed farming is a critical tool for fueling our lives with limited impact on the health of the planet. That's why WWF is partnering with Oceans 2050, a nonprofit organization co-founded by Alexandra Cousteau, aiming to restore and protect our oceans as well as aid and encourage the growth of the seaweed industry. Through this partnership, WWF is advancing the science around the relationship between carbon and seaweed farms, spreading awareness and knowledge on the power of seaweed, and uplifting stories about people and communities that benefit from seaweed farming.