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SUSTAINABILITY LIBRARY 2023 Circularity Ocean Forest

Ocean Forest


Producing sugar kelp is a very efficient way of binding CO2, nitrogen and phosphorous already dissolved in the sea, all elements also emitted from our fish farming activity. Farming sugar kelp does not require any input of freshwater, fertilizer, pesticides, or land. The plant captures the nitrogen, phosphorus, and carbon (in the form of CO2) directly from the ocean. This contributes to reducing acidification of the sea. Sugar kelp also captures carbon from the air, and releases oxygen to the sea (photosynthesis). On average, 1.000 kg (wet weight) sugar kelp contains 26 kg carbon equal to 100 kg CO– which is more than in the same volume of wood. It also captures 2,4kg of nitrogen and 340 grams of phosphorous. 

Feed ingredients from farmed sugar kelp can be used for both agriculture and aquaculture production and is a very sustainable input to animal protein production. Kelp can also become fertilizer or biochar in agriculture, as well as biofuel, and thus improve plant production and make it more sustainable.

All in all, utilization of kelp can contribute to more sustainable food production systems, increased self-sufficiency, and security of food supply.

Ocean Forest AS is a company focusing on R&D and industrialization of the production of low trophic species. Lerøy Seafood Group ASA has a 50% share in this company together with NGO Bellona Holding AS. The production of different seaweed and blue mussel products take place in Lerøy Ocean Harvest AS, a sister company of Ocean Forest AS. The two companies share the same management.

Main Goal
  • To reduce the footprint of our fish farming activities by capturing dissolved nitrogen, phosphorus, and carbon dioxide from the water
  • To develop new ingredients for human consumption or animal feed
  • To develop new species for the Norwegian aquaculture industry

Sugar kelp


One of the focus areas for the companies are production of blue mussels, not for human consumption but mainly as a source of marine protein in feed. Our key knowledge is associated with how to separate the meat from the shell in the blue mussel within seconds without the use of energy. We have also conducted a series of growth studies with Atlantic salmon demonstrating that blue mussel is an excellent fishmeal substitute.

The challenge is to produce a blue mussel meal free of shell fractions on an industrial scale. We have developed “one of a kind” special equipment that will do the job in a very efficient way. The shell fraction can be used in feeds for hens, as a soil improver etc. In addition, blue mussels will also contribute to cuts in COemissions.


The Group has a constant focus on the footprint from our fish farming activities. Feces and uneaten feed on the seabed beneath our cages can represent a local undesired impact on the environment. This issue is addressed with an increased focus on feed control but also how to optimize the raw material used and the amount and physical quality of the feces.

Ocean Forest focuses on the organic matter that reaches the seabed and how we can increase the turnover of this material. Our focus is on polychaeta; how to support the establishment of an active and heathy community of this species and how to harvest the surplus for use in e.g. fish feed for other species than salmon.

In collaboration with the Institute of Marine Research in Norway and the University of Wageningen, we have in recent years conducted a series of studies indicating the turnover rate and species present. We have developed a “polychaeta vacuum cleaner” for harvesting and one of our employees is now studying in detail these challenges in a PhD program with the Institute of Marine Research/University of Bergen.


The Group has a major ongoing program for developing new innovative raw material for fish feed. Historically, Lerøy has been a prime mover regarding the use of Omega-3 fatty acids produced from microalgae to increase the level of Omega-3 in our feed compared to industry standard, and for the introduction of Camelina oil and the ban on ethoxyquin. Last year, we were the first company to start using insect meal in all our freshwater feed delivered by one of our feed suppliers.

Today, we buy the full volume of insect meal the producer can produce. We are also involved in very interesting projects relating to blue mussel meal and seaweed in salmon feed. Both projects are part of a major EU-supported project – “Holofood”, involving a series of issues, such as feed utilization and retention, growth performance, fish health and gut health.

Feed intake and methane reduction with sugar kelp

The Group has also been involved in a series of studies in Denmark (University of Copenhagen and private companies) focusing on fermented seaweed to ruminants (calf and cows). Fermented seaweed as a supplement in feed for calves was very successful. Up to 5% fermented seaweed in the diets improved the feed intake with 2-300% during the first days of feeding which gives the calves a good start. Several in vitro studies also at the University of Copenhagen shows that fermented seaweed reduce the production of methane gas (up to 50%) in the stomach fluent of lactic cows.

The Group is following up these results with future investigations.