New research proves off-shore seaweed cultivation is possible

A new study published today in Algal Research vol. 33 demonstrates that applying a new method of large-scale off-shore kelp cultivation is possible. It can generate efficiencies and be profitable, though innovation is still needed to lower cost per unit seaweed.

The method was designed and tested by the Faroese seaweed producer Ocean Rainforest. The method includes an innovative long-line cultivation rig called MACR (MacroAlgal Cultivation Rig), that was deployed at an exposed site in a Faroese fjord, seeded with two seaweed species – Saccharina latissima (Sugar kelp) and Alaria esculenta (Winged kelp). The MACR has survived since 2010 at a site with up to 6-m significant wave height, high currents and water depths of >50 m.

To make the production profitable, non-destructive harvests were tested – where part of the seaweed blade was left to regrow – in order to reduce the cost of seeding and deploying the lines. Using this approach, up to four harvests were possible over a two-year period, reducing the overall cost of production by around 75%. In this context, an economic analysis showing the cost structure of important aspects of offshore macroalgal cultivation was conducted.

This work has demonstrated that large-scale kelp cultivation is possible using multiple partial harvesting in the Faroe Islands, and highlighted the need for further innovation to lower the cost per unit macroalgae produced.


Urd Grandorf Bak lead author, Industrial Ph.D. student and Research & Innovation Manager at Ocean Rainforest, said: “We are really pleased with the results from these tests. As well as capturing carbon, large scale cultivation of seaweed will create healthy marine environments by balancing nutrients and promoting bio-diversity. The rich nutrient content has given seaweed a ‘superfood’ status and positioned it as a sustainable food and feed alternative, so demand for it has never been greater. Moreover, promising research and development is ongoing using seaweed extractions as a sustainable source for replacing fuel-based products in the form of bio-plastic, bio-energy and textile products. It is an exciting time for this emerging industry.”

The research work was carried out by Urd Grandorf Bak and Olavur Gregersen from Ocean Rainforest, and Agnes Mols-Mortensen from Fiskaaling - Aquaculture Research Station of the Faroes & TARI - Faroe Seaweed Sp/f. The article is available at

Editors notes


The corresponding author of the publication is Olavur Gregersen, Ocean Rainforest, who can answer any question or provide clarifications in relation to the publication. Contact details: / Tel: +298 233080.