Coast 4C untangles complexities of the blue economy through seaweed farming

The world’s coastal communities face mounting challenges from overfishing, pollution, declining marine ecosystems, economic instability and more. While there has been a surge in seaweed farming due to its potential for sustainable economic development, environmental stewardship and social engagement, inadequate support and increasing climate pressures have led to seaweed farms posing a risk to vital marine life.  

Coast 4C addresses this risk by scaling seaweed farming as a nature-based solution, restoring marine habitats, sequestering carbon, and providing sustainable income sources for coastal fishers. Working closely with marginalised coastal communities, Coast 4C aims to grow their stewardship of coastal resources, leveraging unique local ecological knowledge to help protect and restore coastal ecosystems. 

Their work is situated in the Philippines, with plans to expand in Southeast Asia and ultimately globally across tropical coastal areas, with local teams working to integrate regenerative seaweed practices into larger and more effective locally-led marine protected areas—ones that regenerate local fishing zones alongside mangrove, coral and seagrass restoration zones, and plastic reduction and recycling within locally managed marine protected areas. Currently, Coast 4C’s hub-and-spoke model has increased protection of coastal ecosystems from less than 1% to 17.8% in areas under their purview.  

"For Coast 4C, a truly regenerative relationship between people and the ocean is where coastal communities are empowered to act as good stewards of their marine environment, protecting at least 30% of their coastal waters to rebuild fish stocks and restore coastal habitats such as mangroves, seagrasses and coral reefs, whilst also supporting prosperous and resilient coastal economies." 

—Nicholas Hill, PhD, Co-founder & CEO, Coast 4C 

How is Coast 4C different from more mainstream aquaculture solutions?  

Traditional blue economy models often prioritise industrial-scale fisheries, offshore aquaculture, and mechanisation aimed at maximising resource efficiency—practices that, without safeguards, can lead to environmental degradation and job losses. In contrast, Coast 4C applies circular economy principles and community ownership to maintain efficiencies that enhance livelihoods while protecting marine ecosystems. Rather than relying on centralised, corporate-led production, Coast 4C builds cooperative networks of small-scale seaweed farmers, ensuring fair wages, sustainable harvesting, and marine biodiversity protection. 

What sets Coast 4C apart is its commitment to systemic change—addressing the last frontier of inclusion for smallholder seaweed farmers and fishers, many of whom are women. By innovating on scalable systems and processes, Coast 4C not only enhances access to digital and financial services but also increases market access and resilience for these communities. These tools offer broader benefits beyond the seaweed sector, contributing to long-term inclusive growth. The team leverages decades of experience in marine science, deep-rooted community connections (with their operational team members hailing from coastal communities), and emerging opportunities in impact finance to scale sustainable solutions.  

Coast 4C also prioritises regeneration, rebuilding marine ecosystems while strengthening local economies. By working with downstream partners to integrate seaweed into material innovation, there is the opportunity to create high-value, low-impact products that reduce reliance on fossil-fuel-based plastics and chemical fertilisers. 

How is Coast 4C changing the way we approach blue economies?  

Coast 4C is redefining how we think about food from aquatic ecosystems by proving that regenerative seaweed farming can drive both environmental restoration and economic resilience. Business-as-usual seaweed farming often contributes to environmental degradation.

However, building a resilient and profitable industry that can meet growing demands requires regenerative practices that enhance biodiversity, improve water quality, and capture carbon. From a purely financial perspective, investing in sustainable practices is essential to ensuring long-term profitability and market stability—a win-win for both business and the environment. Research suggests that seaweed farming could remove up to 140 million tonnes of CO₂ from the atmosphere annually, positioning Coast 4C’s work as a critical climate solution.

Beyond environmental impact, Coast 4C is shifting the blue economy toward a model of inclusivity and sustainability. By ensuring fair market access for smallholder seaweed farmers, majority of whom are women, they create stable and inclusive livelihoods in coastal communities most affected by climate change. Their work has already resulted in the protection of 5,868 hectares of coastal zones across eight locally managed marine protected areas, increasing marine conservation in these regions from less than 1% to 17%. Over 680 households have been trained in regenerative seaweed farming, with farmers seeing up to a 350% increase in yields and a 400% rise in income.  

By integrating environmental regeneration with economic inclusion, Coast 4C is proving that ocean-based livelihoods can be a force for both climate action and social justice. 

What could the future look like if Coast 4C scales? 

If Coast 4C’s model became mainstream, we could see a fundamental shift in how coastal economies function. Coastal communities—often among the most vulnerable to climate change—would become key drivers of scalable climate solutions, leading the global transition to regenerative ocean economies. Coast 4C’s targets include protecting half a million hectares of coastal zones, ensuring that at least 30% of local waters are under conservation and eliminating plastic pollution from fishing and aquaculture. Scaling their model would demonstrate that economic growth and ecological restoration can go hand in hand, redefining the future of the blue economy into one centered on regeneration, equity and resilience.

All images courtesy of The Earthshot Prize.

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