Ace Aquatec has reported successful results with its first in-water smolt stunner in Norway following a trial at a salmon smolt producer near Bergen. Sævareid Fiskeanlegg, which has supplied many of Norway’s west coast farmers with smolts since 1978, piloted the equipment in August and September.
A smaller and more portable version of Ace Aquatec’s humane stunning technology, the smolt stunner ensures all the fish are culled and not simply stunned, as happens with larger fish prior to slaughter.
Ace Aquatec Northern Europe Regional Manager Preben Imset Matre, who oversaw the Norwegian trial, said: ‘In the smolt stunner, we stun the fish with high electrical output and increased exposure time, so that the fish is fully unconscious and insensible. That means it cannot move, nor feel any sensory inputs, including pain.’
The fish are stunned immediately upon being exposed to the electrified water, with a 100% stun rate being demonstrated by scientists from the University of Stirling through trials at one of the smolt production facilities of Hendrix Genetics, one of the first companies to install a smolt stunner.
The validation work involved taking a sample of around 700 fish and individually monitoring them for between 15 and 30 minutes after stunning. None of the fish showed any sign of recovery during this time. The validation work was performed by research staff from the University of Sterling.
Sævareid Fiskeanlegg typically culls fish which, due to genetic variations, are too slow growing or have disabilities that make it uneconomical, or inhumane, to keep them alive.
‘Our equipment in this case operated at a capacity of about one tonne an hour, which enables the farmers to perform the cull very quickly,’ said Matre. ‘This decreases treatment time, which can be seen as a fish welfare benefit.’
In the trial with Sævareid Fiskeanlegg, the culled fish were collected for processing by pet food brand Omega Plus, a subsidiary of New Zealand King Salmon, which freeze dries the fish and then packages it as treats for cats and dogs.
‘The pet food industry has been booming during the pandemic and people are spending more money on their pets than ever before, looking for sustainable products with health benefits,’ said Matre.
‘The smolt stunner is able to transform fish that the farmer would previously have had to pay someone to remove into a more valuable commodity. It’s a great example of how sustainability can also be good business – and usually is!’
Sævareid Fiskeanlegg confirmed the success of the trial, saying the smolt stunner was easy to use and suggesting the incorporation of a modified dewatering grid that allows farmers to sort the fish between two bins instead of one.
‘The Ace Aquatec in-water smolt stunner has opened up for a better priced by-product,’ said Production Manager Richard Markhus.
‘So, it improves our environmental footprint while creating potential new revenue streams. But most importantly, the fish are culled humanely and efficiently, helping us meet the highest welfare standards, and also addressing the growing demand among pet owners for ethically sourced protein.’
Following the trial, Sævareid Fiskeanlegg has committed to a continuing a commercial collaboration with Ace Aquatec.