Growing salmon smolt to larger sizes than normal before release to sea pens leads to shorter time at sea and less risk of infections in the open.
 
The company Tytlandsvik AQUA from Hjelmeland in Norway has invested significantly in RAS for production of extra large smolt. In smolt farming the fish have traditionally been around 100 gram before transfer to sea cages, but now larger smolt of 200-400 gram (post smolt) have become increasingsly popular. Tytlandsvik AQUA has taken this a step further and is growing large smolt of 800-1 000 gram to benefit even more from the high growth rates in the RAS environment.  

In addition, the company improves its overall fish logistics by utilizing the production capacity of their cage sites even better. Mortality rates have been extremely low at around 0,5% from the time it takes to grow fish from 100 grams to 800-1000 grams. Currently, the company is operating four such RAS each with a capacity at around 8.575 kg feed per day at a proven feed conversion rate at incredible 0,8 that makes it possible to peak at a daily growth of smolt biomass at maximum load at around 10 000 kg per system.   
 
The production volume of each RAS is 7 620 m3 divided on 4 tanks each of 1 905 m3.  
The fourth module was fully commissioned in 2023 resulting in a total feed capacity of 34 tons per day and totally 30 480 m3 production volume at the site. The output of large smolt will be estimated up to 8 000 tons per year. As an alternative, the production facility can be used for growing salmon all the way to market size of 4-6 kg.  
 
The energy consumption is currently around 4-5 kWh per kilo fish produced and is expected to drop towards 3 kWh when full capacity at the farm has been reached. 

Photo: Overview spring 2024 of the 4 RAS under roof built at Tytlandsvik in Norway for production of large smolt at 800-1000 gram before fish are released to net pens for final grow-out at sea to reach 4-6 kg. Source: Tytlandsvik AQUA.