Flexi-Panel - Passive-Grading Device

Whilst the principle of passive grading is not new, the `Flexi-Panel` represents a massive step forward in terms of technology. Other grading grids can offer only a restricted `grading panel area` due to their weight and rigid construction. As well as tending to cause physical damage and scale loss to the fish, these rigid grids did not provide a large enough area to allow a quick and stress free method of grading large tonnages of fish.

Flexi-Panel`s lightweight flexible construction overcomes all these previous drawbacks, allowing very large areas to be easily and safely handled. When the Flexi-Panel is in use the tension on the net keeps the individual apertures at their pre-determined dimensions, thereby allowing an accurate size grade. However, when the tension is removed from the panel it simply folds up in any direction, just like an ordinary net.

The strength, flexibility and lightweight nature of the Flexi-Panel comes from the materials used in its construction. Relatively short lengths of very rigid uPVC pipe are connected together using loops of Dyneema twine to form a series of individual apertures. (Dyneema was chosen as it is the strongest, most stable and abrasion resistant material available). The plastic pipes have a smooth surface and are able to rotate when the fish swim through, thereby eliminating physical damage and scale loss to the fish.

Large areas of Flexi-Panel can easily and safely be used, resulting in fast and stress-free grading of the fish.

For most species of farmed fish there is an optimum harves size, where fish achieve a premium price compared to smaller undersized fish. Therefore a method of selecting the prime fish for harvest, whilst allowing the smaller ones to continue growing, will provide the farmer with a greater tonnage of fish and the maximum possible income. This is exactly what the `Flexi-panel` does.

The direct financial benefit of using the Flexi-Panel to size grade farmed salmon prior to harvest can clearly be seen in the following examples.

HARVESTING USING FLEXI-PANEL, FINANCIAL BENEFITS

Increased value of harvest using Flexi-Panel compared to harvesting ungraded fish:

Based on:

• Harvesting in a cage with 400 ton biomass
• Average weight ungraded 4.0 kg
• Average weight graded 5.2 kg using panel with 67 mm aperture
• Harvest of 100 ton

*based on Fish Pool`s salmon prices in 2018 for the corresponding week, Flexi-Panel software and a perfect grading.

When taking out the larger fish and allowing the smaller fish to grow, it is recogniced that the total outcome from a cage will increase between 10-20%. Instead of harvesting 400 tons from a cage, it should be possible to increase production by 40-80 tons. Increased value of the extra tonnage is in the region of NOK 2 mill-4 mill. Using an average price of NOK 50 per kg.

Using the Flexi-Panel for increased production is the main financial benefit of grading.

OTHER BENEFITS OF FLEXI-PANEL
The wider benefits of using Flexi-Panel include the following:

• Flexi-Panel is very light and easy to use compared to rigid graders.
• The grading operation is very quick and simple to carry out even in large cages and large tonnages of fish.
• The larger the size of grading panel the quicker the grading operation is completed therefore the less stress is put on the fish.
• The large dominant fish are selected for harvest.
• Small fish are not harvested and are therefore grown on to a larger size.
• Continuity of supply of the correct size of fish can be achieved.
• Growth rates are increased as the density is reduced.
• The Food Conversion Rate (FCR) is lowered by always selecting fish for harvest at the optimum size.
• The lower FCR means that you can achieve lower production costs.

WELFARE BENEFIT OF FLEXI PANEL
Using `Flexi-Panel` greatly improves fish farm productivity and efficiency as well as boosting the image of farmed fish.

It is widely recognised that `passive grading` methods are best for ensuring the welfare of farmed fish.

Compared with other grading methods, the welfare benefits include:

• Reduced stress
• Reduced physical damage
• Reduced risk of handling related disease outbreaks
• No starvation required prior to grading, so no loss of growth

The Organic Food Federation - an organisation tasked with the accreditation of organic farmed fish production in the UK - has stipulated the requirement for the use of passive grading systems for all size grading operations in their "Standard for Aquaculture". A representative from the OFF said; "The Flexi-Panel grading system meets all our requirements".

Freedom Foods - the RSPCA`s farm assurance and food labelling scheme dedicated to farm animal welfare - have also stated that "... [Flexi-Panel] equipment can be used by producers in the Freedom Foods scheme...".

Flexi-panel was originally designed for use in salmon farming, but is now used to successfully size-grade farmed trout, cod, sea-bass and sea-beam.

Research and development work is currently ongoing with Tilapia, Barramundi, Cobia and Yellow-Tail.