Industry-scale trials have been carried out at one of Marine Harvest's salmon farming plants in Rogaland. The salmon are pumped up directly from the pens to a vessel that had been especially outfitted for the trials.
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| Current slaughtering methods must be improved. Recent research contributes to that salmon can be slaughtered more humanely and efficiently. |
Trials were also carried out using a system where the salmon swim directly into the slaughtering machine.
Instantaneous slaughter
An Australian machine was used in the trials. The machine kills the salmon instantaneously with a blow to the head.
In the next stage the salmon is cut for bleeding, and transported to a tank containing cold, sterile seawater where it is bled out until the process is completed.
"The trials have documented that the fish are killed instantly when the machine delivers a correctly-aimed blow," says Senior Researcher Kjell Midling of Fiskeriforskning.
Welfare, efficiency and quality
A modern salmon abattoir receives thousands of fish every day. The challenge in connection with this is to develop a slaughtering system that ensures that each individual fish is handled and slaughtered as humanely as possible.
"The objective of the project is to achieve a system that takes into account the welfare of the fish while at the same time ensuring efficiency and optimum product quality. The system shall also have at least the same standard of hygiene as a land-based plant."
In order to avoid any risk of the spread of infection and contamination, all blood and waste materials from the slaughtering process will be stored in on-board tanks.
Quality checks
The trial will now be repeated to check the quality of the salmon after slaughtering.
The previous trials have shown that the quality of the fish is improved when unnecessary stressful situations for the salmon prior to slaughter are avoided.
A further advantage is that it takes considerably longer for rigor mortis to set in, and the degree of rigor mortis not so strong.
This allows a considerably longer period of time for the filleting process, and this means that among other things one can have fresh salmon products in the marketplace much more quickly.
Particularly suited to Southern Norway
The project has also proved that it is possible to slaughter salmon by taking it directly from the pens.
"This method can be particularly advantageous in Southern Norway where high sea temperatures mean that the salmon is much more vulnerable when being handled. One can thus both reduce mortality while simultaneously achieving an improvement in post-slaughter quality," Midling points out.
The results of the project will be made generally available, and Midling is generous in his praise of Marine Harvest for the company's efforts.
"This is work that will be to the advantage of the Norwegian salmon industry as a whole, and the company richly deserves praise for its engagement," says Midling.
The project is being carried out on behalf of The Norwegian Seafood Federation and is financed by The Fishery and Aquaculture Industry Research Fund.