Tunicates, Ciona intestinalis. (Photo Credit: Perezoso)
Plentiful species could be the answer to farmed fish feed problems
Thursday, June 27, 2013, 03:20 (GMT + 9)
A group of researchers is studying tunicates (Ciona intestinalis), the starting point for a research-based innovation project at the University of Bergen and Uni Research. The species eats microorganisms and can be converted into feed for salmon or a biofuel -- and 200 kg can be cultivated per sqm of ocean surface area.
Tunicates are at the very bottom of the food chain in every ocean, but especially off Western Norway, and are the only animals that produce cellulose – and are rich in omega-3 fatty acids.
Now, tunicates are being cultivated experimentally at a pilot facility near Bergen.
As for its uses, the tunicate is the only animal known to produce cellulose, and breaking down cellulose yields sugars that can be used to produce bioethanol.
A more attractive use is for feed for farmed fish, as there is a huge demand for more marine proteins as feed ingredients, but it has been recognised that industrialised fishing cannot increase any more to meet growing demand.
Feed producers are struggling to produce salmon feed containing omega-3, which the fish need but presently comes wild fish. Dried tunicates contain 60 per cent protein and are rich in omega-3 -- and salmon will eat them.
Further, protein production from marine cultivation of tunicates has 100 times the potential per sqm than any land-based protein cultivation, and the food that tunicates need is readily available in nutrient-rich marine waters.
“Our single greatest challenge is cultivating enough biomass per sqm to make operations profitable,” explained project manager Christofer Troedsson of the University of Bergen’s Department of Biology.
“We anticipate a crop of 100 to 200 kg per sqm, which is an extremely high yield. But that is what is needed for profitability because the price per kg is so low,” he continued.
The researchers have achieved this production target at their small-scale facility, and they are optimistic that a similar production level is possible with large-scale farms.
“The second major challenge we face is how much water we can squeeze out of the tunicates,” said Troedsson. “Their body mass is 95 per cent water. To sell the product we have to be able to remove at least 90 per cent and preferably 95 per cent of that water by mechanical pressing.”
He stated that they have managed to mechanically press out 97 per cent of the water, but the process must now be carried out efficiently on harvesting boats, while at the same time hauling several tonnes of tunicates per hour out of the sea.
“Thus production volume and water separation are the two critical factors that must be successfully addressed if tunicate cultivation is to be profitable for private companies in today’s market,” concluded Troedsson.
The project is receiving NOK 8.7 million (EUR 1.1 million) in funding through 2014 from the Research Council of Norway’s programme Commercialising R&D Results (FORNY2020).
By Natalia Real