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Preline - fish farm designed for the future
The purpose of a self-contained, floating fish farm is to optimise conditions for the fish during their first months in the sea. This provides better conditions for growth, improved welfare and protection against disease and salmon lice.
The purpose of the self-contained Preline fish farm is to produce post-smolt – a larger and stronger smolt – that is released to sea in open cages at a weight of between 0.5 and 1 kg.

New developments in fish farming are taking place in Sagen, Hordaland. This is the site of the first Preline facility, which is already reporting good results. This means the start of fish farms with even better conditions for growth, good protection against disease and salmon lice – and no accidental release. The idea and the philosophy are to provide the smolt – the young fish moved from fresh water to a marine environment – conditions that are as perfect as possible during the first five to six months in the sea.

The results provided by the prototype are so good that a new facility double the size of the first one is already being planned.

The new technology involved will also allow use of areas currently not suited for fish farming and make these valuable areas for producing food at sea.

– The principle and concept have proved very successful. The experience we have gained with the prototype established in 2015 is that both the idea behind the biological factors and the technological equipment both work, explains Harald Sveier, Chairmain of the board for the Preline project and Technical Director at Lerøy.

In practice, this means that Lerøy has had a steep learning curve. A lot of the technical equipment on the prototype has been modified and upgraded during the test period. Harald Sveier also explains that experience shows good fish welfare and low mortality.

– The fish that start the cycle in the Preline facility have good growth and have become very strong by the time they are moved to ordinary cages for continued growth. The number of lice treatments for this fish, after they have been transferred to open cages, is down by a total of 90 percent. We are very happy with this figure, confirms Harald Sveier, underlining that this demonstrates the importance of farming fish that are as robust as possible.

Optimised conditions
The normal procedure today is to have smolt in open cages, but this is difficult as we have no control over weather conditions, tidal flow, the phases of the moon and temperature. These difficulties are practically eliminated in a Preline facility, where water flow and water quality are managed and controlled. By establishing a constant flow of water, the fish are constantly in movement and it has now been scientifically documented that physical exercise results in a more viable and stronger fish.

Action against salmon lice

  • Experience shows that salmon from a Pipefarm facility are stronger and less exposed to disease even after they have been moved from the self-contained farm. This is evident as there is practically no requirement for medication or mechanical treatment for fish after they have been released from a Pipefarm.
  • The extent of medication has been low for several years and remains so. Lerøy has achieved this via a strategy based on the principles of integrated parasite control. This involves a number of measures applied in rotation, not allowing the salmon lice the time to adapt to specific measures. The measures comprise e.g. monitoring, action limits, structural, mechanical and biological measures and treatment.
The fish that start the cycle in the Preline facility have good growth and have become very strong by the time they are moved to ordinary cages for continued growth. The number of lice treatments for this fish, after they have been transferred to open cages, is down by 90 percent.
HARALD SVEIER, CHAIRMAN OF THE BOARD FOR THE PRELINE PROJECT AND TECHNICAL DIRECTOR IN LERØY

The Preline facility, which was launched in Samnanger municipality in Hordaland, is designed as an oval, floating pipe with a volume of 2,000 m3. The fish are placed in the pipe, which has a constant water flow.

In a traditional fish farm, salmon spend approximately 15 months in the sea – from smolt stage to harvest. With Preline, the fish spend six of these 15 months in a self-contained facility, thereby providing conditions for salmon that are optimal during the most critical months of their lives. At the same time, this reduces production time in open cages from 15 to eight months. Experience shows that salmon that start their lives in the sea in a self-contained fish farm such as Preline grow stronger and are less exposed to disease than fish in open cages.

Increased fish welfare
"When compared with traditional fish farms, we have much more control over both the environment and fish health, as the fish have better protection against parasites, bacteria and viruses. With the Preline facility, we pump water up from depths of 30–35 metres, and there are fewer sources of infection in this water when compared with surface water,” explains Harald Sveier.

In addition, the design of the facility provides significant reductions in the risk of accidental release when compared with a traditional marine cage. The risk of accidental release is therefore expected to fall and fish welfare to improve with the use of Preline. By the end of 2017, a total of six generations had been released to the facility.

When compared with traditional fish farms, we have much more control over both the environment and fish health, as the fish have better protection against parasites, bacteria and viruses.
HARALD SVEIER

New prototype under development
Work is now under way to develop prototype number two based on the experience gained.

"This will be a new facility double the size of the existing one. This time, we have recruited even more technical expertise, both internal and external, to solve the technological challenges we have encountered so far."

Harald Sveier explains that Lerøy has been working on the development of the new prototype for a while now, and has applied for development licences based on the future technology developed under the new project, known as Pipefarm.

"We aim to get started on testing the next stage of this technology in 2018," confirms Harald Sveier.