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Shock and awe

A device which renders fish unconscious before they even leave the water – decreasing stress levels and offering a more humane alternative to traditional mechanical stunners – is in the running for one of aquaculture’s most prestigious prizes.

The system, designed and built by Scottish firm Ace Aquatec, is one of three finalists for this year’s Innovation Award at Aqua Nor.

The Ace Aquatec stunner can be used for multiple species, including crustaceans.
The Ace Aquatec stunner can be used for multiple species, including crustaceans.

Traditional stunning systems rely on fish being pumped out of the water and then killed by pneumatic, percussive or electric devices, often mechanical ones. The drawbacks associated with these methods are many. 

  • There are problems with fish that differ in size – some fish are not properly stunned.
  • The fish are stressed, triggering cortisol to release into their body – which in turn lowers quality of the filet.
  • There is a significant limit to how many fish it is possible to stun in a given time – often one at a time.
  • The systems are often mechanical – requiring spare parts and repairs.
  • Mechanical systems are also prone to downtime.

Ace Aquatec claims to have found the solution to all these problems, and focus especially on fish welfare and humane stunning and killing of the fish in their presentation of the technology.

“We saw that fish farmers had to compromise between efficiency and humane stunning. Our system stuns 100% of the fish, every time. It also stuns them in the seawater – so they are not stressed before they are rendered unconscious. Some methods of slaughter cause fish to die over long periods of time – we wanted to improve this process for aquaculture and wild fishing vessels, for all species including crustaceans,” says Nathan Pyne-Carter, MD of Ace Aquatec.

While here are other electrical stunning technologies on the market but these are used after the fish is already on a dry conveyor belt – on their way to be bled. By this time they have both suffered and been stressed. It has taken the engineers at Ace Aquatec close to 10 years to perfect the electric current – too much, and you damage the flesh, too little and the fish is not properly stunned. Ace Aquatec can now show independent research studies that document both that there is no damage to the fish flesh or skin, and that the fish is 100% unconscious before bleeding and slaughtering.

“We’re not worried about being copied for quite some time. This is precision work and finding the right settings and equipment is extremely hard,” says Pyne-Carter.

Multiple applications

Since the technology works regardless of fish size, it is transferrable to many farmed species other than salmon and trout, such as yellowtail, cod, seabass, seabream, halibut and turbot. And, at a lower setting, the system can be used as an anesthetic for vaccinations. It has also been adapted to stunning crustaceans and prawns.

The system has only one limitation when it comes to stunning rates; the flow speed of the pumping system. How much you get out of the technology depends on the pumping system used by the fish farmer.

Recognition

Pyne-Carter is thrilled to have been nominated for the 100,000 kroner (£9638) award.

“We think it is really exciting to be nominated for the award. An acknowledgment by such a prestigious body, accompanied by such fantastic companies as the other nominees, is really a recognition we appreciate. We owe our greatest thanks to our customers. They’ve helped us refine and further develop our technology every step of the way. The final product is nothing more than an expression of what they’ve told us they need,” he concludes.

Ace Aquatec will be demonstrating one of their pre-pump systems on the stand of their Norwegian distributor, Sterner AS, located at stand D-324.