Offshore Tank Fleet would use RAS to produce large-size smolts
By Cathryn Primrose-Mathisen
The Wilsgård Offshore Tank Fleet (OTF) is a barge-based smolt production concept under development by Norway’s Wilsgård Fiskeoppdrett AS for use in Norwegian fjords.
A key part of the design is a recirculating aquaculture system (RAS) explains managing director Fredd Wilsgård. “The OTF is 100% closed and has no emissions. That means that we clean all the water that comes in and we clean all the water that goes out.”
By cleaning the water that comes into the OTF, no unwanted organisms (bacteria, sea lice, etc) enter the production system. Also, the production water is cleaned and sterilised before it leaves the system. And it’s 100% secure against escapes.
One of the goals of the OTF is site area optimization. Since the OTF cleans water coming in and going out of the system, it will neither be affected by nor affect the environment. As Wilsgård points out, “this means that you can establish larger OTFs, more OTFs and that they can be located in the same fjord. If you look at traditional area use at a site, 200 × 600 metres, you can place six OTFs in such an area and deliver large smolt at up to 70 traditional concessions.”
The OTF is designed to take on fry at 30–40 grams and rear them to 500 grams before the fish are transferred to traditional fjord-based cages for a period of about 12 months. Since the OTF takes fry into production, the area required on land is also significantly reduced.
The company has applied for eleven development licenses, with a total maximum allowed biomass of 8580 tonnes for the OTF.