News 2016-05-09

Several environmental benefits from using sea squirt in fish farms

Sustainable fish, bioenergy and cleaner water can be the results of creating a local circular production system by integrating fish farming with the cultivation of sea squirt and macro algae. In the sea outside of Lysekil in Sweden the cultivation of sea squirt is already ongoing and will now be further developed.

The fast-growing sea squirts grow in cultivation strips that are submerged in the sea. In the same way as mussels are nourished by filtering large volumes of water from plankton and bacteria so are sea squirts, which in turn leads to the removal of nitrogen and phosphorus from the sea when the sea squirts are harvested. Since their growth rate is about two centimetres per month they also acquire a significant biomass quickly. In the demonstration project, already underway in Lysekil, sea squirts are cultivated and then turned into biogas and eco fertilizer. The concept will now be develop further in order to create integrated aquaculture fish farms and is conducted by IVL, the innovation company Marin Biogas, the municipality of Lysekil, the fish feed manufacturer Raisioagro and the fish farming company Brightwater Fish.

- There are several advantages with sea squirts. They take up nutritive salts from the sea and also work as a water filtration system, cleaning the water from parasites, which in turn benefits the fish farms. They also provide nourishment to macro algae which leads to them growing faster, says Mikael Olshammar, project manager at IVL.

Since sea squirts absorb nutrients, the net impact of fish farming on the ocean is dramatically reduced in this integrated aquaculture system. Sea squirt can also, apart from being used as a base for the production of biogas, being used as a protein source for fish feed. There is a large demand among Swedish fish farmers for access to sustainable fish feed that does not deplete marine resources and that can replace fish flour and soybeans.

- This is a pilot project aimed towards developing a system of integrated aquaculture. There are large untapped potential to develop marine production systems in Sweden with our long coastlines, which could in turn create significant employment opportunities in rural areas.

The project Integrerad akvakultur – Innovativt marint produktionssystem has received financing through Vinnova‘s program Challenge-driven innovation, and is now establishing a consortium of stakeholders from across the value chain in order to build the integrated system.

For more information contact: Mikael Olshammar, mikael.olshammar@ivl.se, phone: +46 10-788 65 08