Live salmon in well boats – a thing of the past?

Experiences from two FHF-financed projects at Marine Harvest in Rogaland and plans in the Norwegian aquaculture industry for the years ahead indicate that processing directly from the cage will increase in volume.

The findings from Nofima Marin show extremely positive developments concerning efficiency, welfare, quality, infection and hygiene, but this method requires the fish to be killed instantaneously and without causing stress.

Canada and Tasmania leading the way
The processing of farmed fish directly on board the vessel is mostly practiced in Canada and in the Australian state of Tasmania.

This method is called "dead haul", simply meaning the transportation of dead fish.

There are many reasons these countries have chosen this technology, but the main reasons are probably the industry’s moderate size (in relation to Norway) and the lower investment costs in comparison with large well boats.

Slaughtering salmon using this method requires only 20-30 containers of ice and water onboard the feeding boat and sufficient crew to club the salmon to death. The primitive variant of this method is probably best suited to fish farms that will only harvest 10-20 tonnes of fish per day.

More centralisation and larger processing plants in Norway

The industry in Norway has developed with increasing centralisation and steadily fewer but larger processing plants. High labour costs do not make manual killing an option in Norway.

The use of CO2 to stun the fish, so the fish could be bled without damaging the product, was introduced at an early stage.

Holding cages offer flexibility in relation to well boats, but also major challenges because the facilities at the harvesting plants are often not optimal for holding live fish.

The first percussive stunning machines
A decade ago, the first percussive stunning machines were developed, which made the killing of salmon easier and more efficient.

In 2002, behaviour-based percussive stunning machines were developed by Australian company Seafood Innovations, which kill salmon instantaneously when they enter the machine.

The method was developed outside Norway (Scotland, Canada and Tasmania).

It was not until the new regulation prohibiting the use of CO2 came into force on January 1, 2007 that interest in new slaughtering methods really increased in Norway.

In the transitional period until July 1, 2008, there was most interest in stunning by electric shock, but this is not a viable option for processing directly from the cage. The chance for injuries is too large and the time before rigor mortis sets in is too short.

Transportation of live salmon is demanding
In Southern Norway, transportation of live salmon is particularly difficult owing to high summer temperatures and low winter temperatures.

Salmon that have suffered from pancreatic disease are also too weak, and mortality during transportation and in the holding cages was a challenge from both a financial and welfare perspective.

Consequently, Marine Harvest (southern region), in collaboration with the Fisheries and Aquaculture Industry Research Fund (FHF), started a series of trials to evaluate processing directly from the cage. All the trials were carried out by Nofima Marin.

Gentle and stress free
The trials were carried out on board Napier AS’s well boat "M/S Tauranga" in the winter of 2007.

These trials showed that with gentle handling and killing with a blow to the head, more than 30 hours could elapse before rigor mortis sat in.

The salmon never became so hard that it could not be gutted or filleted in contrast to using electricity or CO2. Quality and microbiology were at the same level as conventional slaughtering at Marine Harvest.

In the autumn of 2007, the system’s capacity was tested on the purse-seine coastal vessel "M/S Sørfold", and "Tauranga" was then converted into Europe’s first salmon processing boat.

After a commissioning phase in the winter of 2008-2009, full-scale documentation will now be carried out in both high temperature (September) and low temperature (February).

This phase is also a collaborative project with FHF and Nofima Marin, which will also work with the problems related with this method on a smaller scale at the experimental processing plant at the Tromsø Aquaculture Research Station.

Big expectations
Tauranga and Marine Harvest both have big expectations for the processing vessel, which has become safer and more efficient.

In addition, as it no longer has problems associated with mortality during transportation, it can transport three times as many fish (250 tonnes as opposed to 85 tonnes of live fish).

As the vessel always travels with a closed well, the fish cannot be contaminated nor can they contaminate other salmon farms they pass at sea.

The planned FHF project will be administrated by the Norwegian Seafood Federation’s Fillet Forum Salmon, and will chart all handling of salmon that could impact on quality or food safety.

The project has generated considerable interest in the industry, and in addition to other well boat companies there are now some smaller fish farms that want to commence processing directly from the cage.

The project is scheduled to be completed in the summer of 2010.

"However, live salmon in well boats will continue to be the most important transport method for many years to come, but processing directly from the cage will increase in volume," believes Project Manager Kjell Ø Midling. "And who knows, in 20 years’ time maybe the rest of the slaughtering and processing line has been moved on board the boat?

Seafood industry  

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