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Establishing Environmentally and Commercially Sustainable Techniques for Farming Seaweed

Sustainable Techniques for Farming Seaweed

Carly Daniels, Ian Ashton, Renewable Engergy, University of Exeter

Key findings

  • Seaweed cultivation is a growth area in sustainable food production but also shows huge potential for combating ocean acidification and providing wider ecosystem services.
  • Seaweed is extremely versatile, and can be used in food, biofuels, bioplastics, pharmaceuticals, medicines and even clothing!
  • Cornwall is playing a key role in the development of seaweed aquaculture in England.
  • This study will gather practical, biological and engineering data to explore how seaweed cultivation can be best achieved in a sustainable way.


Seaweed is a healthy, sustainable source of food with a large global market. The global seaweed industry is worth over $6 billion per annum (equivalent to approx. 12 million tonnes in volume), 85% of which is produced as food products for human consumption. The algae cultivation industry is set for expansion in the UK, as the health and nutritional benefits of seaweed consumption become clear. Providing a sustainable source of protein, omega-3, iron, a range of vitamins and minerals and other key nutrients, seaweed is expected to play an important role in new diets, including the increased prominence of plant-based diets in reaction to new data on food-related carbon emissions. It is these added benefits and diverse uses of seaweed that make them a prime candidate for sustainable product development.

Cornwall is now at the forefront of these developments! The University of Exeter have teamed up with the Cornish Seaweed Company to understand more about seaweed cultivation in the South West. The work, supported by the European Maritime and Fisheries fund, brings together a diverse team of experts including Aquaculture experts - Westcountry Mussels of Fowey and Hortimare, along with scientists from Plymouth Marine Laboratory. The team will gather practical, environmental, biological and engineering data alongside alternative use assessments to encourage and inform future investment in seaweed cultivation.

Tim van Berkel, Managing Director of the Cornish Seaweed Company, said; “Our success is a huge step towards creating a truly sustainable food and resource economy, and we are proud to be on the forefront of this important development.” Tim adds "Five years ago hardly anyone had thought of seaweed as a commercial product. Now we are realising the enormous potential it has. From food and livestock feed to biofuels, bioplastics, pharmaceuticals, medicines and even clothing, there is hardly anything that seaweed cannot be used for.”

The project reached its first major milestone on a sunny day in November 2019, when some 150+ seaweed cultivation lines were deployed at sea. These lines will spend the next 6 months in the ocean growing various seaweeds including sugar kelp and other local seaweeds all originating from local populations. Scientists will measure the growth of the seaweed to evaluate yields resulting from different cultivation processes and will look to identify environmental benefits associated with seaweed farms.

UoE Project lead Dr Ian Ashton of the Centre for Offshore Technology in Cornwall said “It is great to work with an up and coming local businesses, helping overcome the challenges to develop a product that is both commercially and environmentally sustainable.”

UoE Senior Research Fellow Dr Ross Brown from the centre for Sustainable Aquaculture Futures said: “Seaweed cultivation potentially has a wide array of environmental benefits, including mitigating harmful algal blooms (HABs) and providing habitats for marine species, as well as helping to combat climate change. This project will take an important step in evaluating these potential benefits.”

Post Doctoral research Fellow Dr Carly Daniels said: “Europe is rapidly falling behind the rest of the world when it comes to growing its own seafood and this project is vital in addressing that imbalance in a sustainable manor. Like plants on land, seaweed provides positive environmental benefits. By removing carbon from the environment and storing it, seaweed acts as a carbon sink, helping to mitigate against ever growing concerns of increased ocean carbon dioxide levels, and thus ocean acidification. In a nutshell we are assessing whether it is possible to grow crops at sea in passive, environmentally friendly systems.”