Chicken feed


Maybe it’s time to revisit a bright idea from the 1990s?

Industry critics regularly refer to comments, made by the Scottish Parliament’s Rural Economy and Connectivity (REC) Committee in 2018, to the effect that that “the status quo is not an option”.
In fact, when it comes to salmon farming the status quo has never been an option. From the earliest days, improvement and innovation have always been at the forefront of development, otherwise we would still be farming a few hundred tonnes of salmon in small wooden pens in the sheltered waters at the head of some Scottish lochs. The salmon farming industry has moved significantly forward from those early days.
It has not all been plain sailing, however. It is only necessary to scan the pages of back issues of Fish Farmer magazine to see that innovation has not always been successful, but that is part of the learning curve in what is still a relatively new sector.
Given that this issue of Fish Farmer looks at innovation (see feature, page 52), I thought that I would relate my own experience of trying to investigate a potentially innovative solution. In those days, there was no real help for new start-up businesses, especially when it came to innovative ideas and certainly no Dragon’s Den type of TV programme to highlight the difficulties of innovation on a limited budget.
The concept of the innovation came from my time when I was working as the fish specialist for an animal nutrition and healthcare company. I was responsible for the launch of the first dedicated range of fully licensed in-feed medicines and one of the questions I began to ask was how we could ensure that all the medication administered was actually consumed by the fish. This was not a problem encountered by my colleagues specialising in other species, since medicinal feed fed to a terrestrial farm animal that is uneaten remains in the feed trough and can be seen and recorded. Back in the early 1990s, once pellets left the feed scoop, there was no guarantee they would be eaten by the fish and certainly not in sufficient quantity to produce a beneficial effect.
It was clear to me that the treatment had one single requirement and that was to pass through the water column in the pen so it would become accessible to the fish. It occurred to me that the feed didn’t need to pass down through the water column but could just as equally pass up through it. Instead of feeding the treatment from the surface, why not feed from the bottom of the pen and let it rise to the surface where it would be seen by the farm staff as an indicator of whether it was consumed or not?
Trout feed is manufactured to be buoyant and float on the surface. The challenge was how to get a buoyant feed down to the bottom of the pen and then release it in a controlled manner. This was the real sticking point.
My eureka moment came as I wandered around the stands at the Pig and Poultry Show at the National Agricultural Showground. Food is distributed around poultry sheds by a simple system using chains and disks running through pipework. Every other link of the chain is a disk that is just smaller than the diameter of the pipe. Feed is trapped between the disks and is dragged around the pipework, filling the various feeders around the sheds. I could see that using this system, buoyant feed could be taken down to the bottom of the pen and released.
This system works, but the logistics of fitting a feed delivery system in salmon pens during the early 1990s proved more difficult than on paper, especially on a limited budget. It was made even more difficult because the Italian manufacturers of the chain disks, after initial talks, decided to build a prototype before a design had been agreed, and it was not as I had envisaged. One doesn’t look a gift horse in the mouth, but this prototype was over-engineered and designed to sit above the pen when not in use, which was not seen as practical. It didn’t help that McConnell Salmon decided to trial the unit at what was probably its most remote site in the Outer Hebrides.
A fundamental issue was why any farming company would want to consider the installation of a large stainless-steel structure on each of its pens simply as a way of administering medicated food? The answer is that this reverse feeding method had other, more interesting benefits.
More than 20 years later, it is only necessary to look at the idea of the snorkel pen to understand the real attraction of this feeder. The snorkel pen is designed to keep the fish low in the water column out of the reach of larval sea lice which tend to congregate at the sea’s surface. Even now, using the latest feed technology, the fish are encouraged to rise to the surface to take the feed, right into the sea lice zone.
Reverse feeding from the bottom of the pen would encourage the fish to feed low down in the water column and reduce the contact between them and larval sea lice. Incorporating a feeder into existing pens would make a lot more sense than investing in the snorkel or semi closed unit. In the days before the widespread use of video technology, reverse feeding would also reduce the amount of waste feed.
This innovation was ahead of its time. The cost savings were not sufficiently large to drive its development, so it just didn’t happen then. Over the ensuing years, I have suggested that others look at it, but it seems that the idea of reversing existing feed technology is just a step too far, despite the clear benefits. I believe that a simpler feeder could be attached to existing technology, so that the only difference today would be that once the feed arrives at the pen, it is taken down below the surface rather than administered at the top of the pen.
Given the cost of sea lice to the industry, it is surprising that this innovative approach has never been investigated further. It just needs someone to champion it.


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