A slimy marine organism fit for biofuel and salmon feed

It sounds too good to be true: a common marine species that consumes microorganisms and can be converted into much-needed feed for salmon or a combustible biofuel for filling petrol tanks.

And it can be cultivated in vast amounts: 200 kg per square metre of ocean surface area.

Tunicates (ciona intestinalis) is the name of this unexpected source of such rich potential. The species is the starting point for a research-based innovation project being carried out by researchers and innovation specialists in Bergen. The idea was hatched by a group of researchers at the University of Bergen and Uni Research.

Produces cellulose and contains omega-3

The yellowish, slimy growth that many of us have come across on ropes that have lain in seawater is the marine organism known as tunicates.

Tunicates are basically living filter tubes that suck bacteria and other microorganisms into one end and excrete purified water out the other end. This is how tunicates feed – at the very bottom of the food chain and without competing directly with fish or other marine animals higher up in the chain. At the same time tunicates clean the fjords and coastal areas.

The fact that tunicates are also the only animals that produce cellulose – and that they are rich in omega-3 fatty acids – makes them a potential alternative for bioethanol and as a feed ingredient for farmed fish.

Inhabiting all oceans

Tunicates grow very quickly and year-round. Found in every ocean, they particularly thrive in cold, nutrient-rich waters such as those around the quays and coastal rock slopes of Western Norway.

Since there are no marine predators feeding on tunicates, some 2 500 to 10 000 individuals can grow undisturbed in 1 m2 of ocean surface area.
Other than the Japanese and Koreans, who eat tunicates, no one has paid them much attention until now.

Similar to mussel cultivation

For the first time ever, tunicates are being cultivated experimentally at a pilot facility in Øygarden, a small island community near Bergen.

The production method resembles the cultivation of mussels. At a facility in a small finger of a fjord, long plastic sheets are anchored to the seabed and held vertical by buoys. Between these sheets flows seawater teeming with the microorganisms tunicates need.

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