The Blue Fields Project
A Demonstration of Offshore Deep-Cycling Limu (Seaweed) Farming in Hawaiʻi Waters
Project Overview:
The Ocean Era MARINER team has launched an offshore seaweed cultivation array, located 8 nautical miles off Makalawena Beach, Hawaiʻi, as the final phase of a five-year Department of Energy–supported initiative. Anchored at 400 meters depth, this demonstration project tests whether Hawaiʻi’s deep ocean environment can support native limu (seaweed, or macroalgae farming).
Why Seaweed?
Fast-growing native seaweeds like Caulerpa (green) and Halymenia (red) are promising sources of delicious foods, and biomass for other products and processes:
No fresh water or land area needed: Can be grown in offshore waters
No Fertilizers Needed: Use deep-sea nutrients, not synthetic inputs
Ecosystem Benefits: Create habitat and increase biodiversity and productivity
Potential Products: Edible limu, soil additives, and biomaterials
How does the System work?
Our submersible ring mimics natural nutrient upwelling, but without the upwelling:
Weekly cycles lower the ring down to 200 m depth, to absorb the nutrient-enriched limu is then brought up close to the surface, where the limu uses sunlight to grow
Natural ocean currents stimulate limu growth.
Acknowledging Our Impact
While we aim to reduce dependency on land-based resources, this project does require support systems that use conventional energy:
Regular fuel-powered boat trips for monitoring and maintenance
Use of scuba tanks filled on land via electrical compressor systems
We’re not presenting this as a zero-emissions operation — instead, this pilot strikes a balance between practicality and progress, helping us assess the real-world scalability and trade-offs of offshore macroalgae farming.
Early Results & Next Steps
Halymenia has shown up to 8% daily growth in land-based flume tank simulations
Caulerpa trials indicate fast, reliable growth in nutrient-enhanced conditions
In this offshore trial, we’ll monitor survival, growth, and ecological impact
This project is a mock commercial trial, designed to test technologies and inform future designs that could one day scale with cleaner energy and more efficient logistics.
Why It Matters:
The Blue Fields project demonstrates a first-of-its-kind, site-specific model for regenerative ocean farming in Hawaiʻi. With continued refinement, this approach could:
Support Hawaiʻi’s food security and ocean health
Help reduce fertilizer use and restore coastal ecosystems
Contribute to better nutrition for Hawai`i’s consumers. We’re proud to share this final phase with our stakeholders — not as a finished solution, but as a tangible, tested step toward one.