Reflections from the 25th International Seaweed Symposium (Victoria, 2025)
- Scotland Seaweed
- May 26
- 5 min read
By Rhianna Rees, CEO of the Scottish Seaweed Industry Association (SSIA)
Earlier this month, I had the opportunity to attend the 25th International Seaweed Symposium (ISS) in Victoria, representing the Scottish Seaweed Industry Association (SSIA).
With 723 delegates from 43 countries, including 165 students and 66 Indigenous participants, this was an exciting global celebration of all things seaweed, spanning science, industry, policy, culture, and innovation.
The conference was a chance to reconnect in person with international peers, including colleagues from the Pacific Seaweed Industry Association and SeaGrant Alaska, and to understand in the latest thinking and research in phycology. Topics covered included: carbon accounting, fermentation trials, novel processing techniques, and many international case studies. I tried as much as possible to be present in talks that I felt would be relevant to our members.
One major thread running through the event was the role of Indigenous communities in ocean stewardship. In many sessions, Indigenous speakers from Canada shared their philosophies and practices, describing the ocean not simply as a resource, but as a shared and sacred space of biodiversity. Their voices added essential context and reminded us of the responsibilities that come with any form of marine cultivation or use.
While there was a strong academic presence from the UK (including many familiar faces from SAMS) I appeared to be the only delegate from the UK representing the seaweed industry. This was surprising given the number of commercial and applied conversations taking place. When I introduced myself as running the "Scottish Seaweed Industry Association", I often received the response, “Oh yes, I know SAMS”, a reminder that the distinction between research institutions and industry bodies isn’t always obvious internationally, especially when we both have “Scottish” and “Association” in our names.
Despite this, the industry turnout at ISS was substantial, and the energy around seaweed’s commercial applications was high. There was a dedicated industry reception, and many sessions explored real-world bottlenecks, collaborative models, and scalable innovations. The conference provided a valuable space where researchers and businesses could connect directly, although the gap between academic research and industry needs was apparent in some conversations.
The conference opened with a plenary from Professor Emeritus Louis D. Druehl, a pioneer of kelp cultivation in North America. With a career spanning more than 50 years, Louis has contributed to everything from taxonomy and farming techniques to restoration and public education. His company, Canadian Kelp Resources Ltd., was one of the first commercial seaweed farms outside of Asia, and his bestselling book Pacific Seaweeds continues to introduce new generations to the beauty and complexity of macroalgae. He delivered the keynote opening the 25th edition of ISS, reflecting on the evolution of seaweed science from the 1960s to today.
Later in the week, a gathering of global seaweed experts, dubbed the “Seaweed Wizards”, featured Michael Borowitzka, Charles Yarish, John Bolton, Michael Guiry, Eurico Cabral de Oliveira, and Masao Ohno. Each offered their thoughts on the challenges and opportunities ahead for seaweed. Several (and at times condradictory) themes emerged from this panel:
The need to define clear product goals.
The importance of biorefineries and zero-waste systems.
The tension between pursuing innovation and avoiding “doing too many things at once.”
While biorefineries remain a popular model, the consensus was mixed. Some experts said they felt biorefineries are only viable if you can identify one high-value output and focus on delivering it exceptionally well.
To improve relationships between industry and academia, industry should be asking academia straightforward questions like, “Seaweed is mostly water, how do we reduce water content efficiently to cut transport costs?”
Carbon sequestration was another hot topic. Dr. Jean-Baptiste Thomas of KTH delivered a powerful keynote exploring the environmental realities of Asparagopsis taxiformis in methane reduction. His LCA work shows that while methane emissions from livestock may be lowered, the overall carbon intensity of cultivating, processing, and transporting the seaweed currently outweighs the benefits. It was a timely and sobering reminder that green claims must be grounded in rigorous analysis, not just good intentions.
Fanny Noisette presented findings showing little to no carbon sequestration below cultivated seaweed farms, and suggested the primary carbon benefit lies in the standing stock harvested, roughly 3.6 kg of carbon per hectare per year (increased by longer grow-out seasons and biofouling). Qing Wang et al., in their poster on large-scale seaweed cultivation in China, framed cultivation as a potential nature-based solution stating the benefits in controlling euthrophication, reducing carbon, and mitigating climate change.
Fermentation was another lively area of discussion. Evangelia Zioga’s talk explored co-fermentation of different seaweed species, with results showing that fermentation can reduce the bioavailability of certain minerals like iron and sulfur in brown seaweed matrices. Meanwhile, Caroline Østergaard Klein shared salt pickling trials for Saccharina latissima and Alaria esculenta, which achieved short-term stability under acidic conditions, but showed some degradation risks. Anna Thora Hrólfsdóttir further explored acid preservation techniques and the resulting changes in trace mineral composition in Icelandic seaweed.
On innovation, Susan Løvstad Holdt presented fascinating work on novel processing methods aimed at reducing water content and improving shelf life. Blanching and pulsed electric field (PEF) techniques were shown to reduce iodine levels by up to 50% and are scalable for industrial use, micro-dryers were not recommended. She also explored the potential of brining as a preservation technique (though refrigeration remains a challenge for remote producers). These developments represent more than just drying, they are crucial for improving safety, nutritional stability, and storage across supply chains, more information on her work here.
Acadian Seaplants shared updated research on sustainable wild harvesting, showing that maintaining exploitation rates of 25% or lower in Ascophyllum nodosum allows for healthy regrowth and long-term yields. This is especially relevant as conversations around sustainable extraction intensify across North America and Europe.
The SeaMark project, presented by Urd Grandorf Bak, gave an optimistic vision for European seaweed processing. Partnering with Oceanium, Algaia, and Fermentex, they are working on scaling up seaweed-based ingredients for both food and health applications, including prebiotics to support the gut microbiome.
In a compelling session on seaweed in animal feed, John Church shared findings on Saccharina latissima and Mazzaella japonica feed trials in beef cattle. Interestingly, applying stress to the seaweed (through hydrogen peroxide treatment) led to improved bromoform levels and a better Omega-6 to Omega-3 ratio (1.6:1), offering a promising route for functional feed development.
GreenWave USA also gave a preview of their upcoming State of the Industry report for North America. They are currently working with Hortimare on improving seeding methods and exploring the formation of farmer cooperatives to reduce costs and pool infrastructure, an idea that closely echoes some of the conversations we’re having in Scotland. However, the challenge of aligning cooperative models with diverse end-uses is ongoing.
And finally, Dr. Kati Michalek of SAMS presented the final findings of the ASTRAL project, which looked at improving kelp production on the Scottish west coast. The result is a wealth of open-access data, technical guidance, and practical lessons, particularly useful for IMTA farms navigating real-world complexity.
The closing keynote came from Dr. Jang K. Kim, who shared insights from 25 years in Korean seaweed aquaculture. He credited the sustained success of Korea’s seaweed sector to strong government support at both early and later stages. His advice was simple and powerful: “New markets need a sustainable market first.” without long-term commitment and clear demand, innovation can only go so far.
The International Seaweed Symposium left me with a lot to reflect on. It reaffirmed the importance of staying globally connected, of grounding innovation in practical reality, and of ensuring that research and industry continue to speak to each other. It also made clear that the SSIA has an essential role to play in raising the profile of Scotland’s seaweed sector on the global stage.
Hopefully next time, I won’t be the only one flying the industry flag for the UK.
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