WOOL AND FISH!

Enjoying a few pints of Sussex ale in a pub local to me, I am having a conversation with Howard Venters about the intricacies of wool, the politics and trade. When I mentioned to him I write in various marine biology and fish farming magazines; he mentioned about writing an article about the application of wool in my field of work. Initially I was a bit dubious about writing in a publication in a world so far from mine, but Howard’s enthusiasm for wool is infectious – as is the way when talking to people about most subjects when they are passionate about their trade or subject.


    So I began researching the use of wool in my trade – fish farming and fishery management. The world of wool, sheep and land-based animals is something I have little knowledge or experience. In fact the only experience I have had with sheep is the time a particularly boisterous domesticated ram butted me as I repaired a fence for The National Trust!

So why have I been given a chance to write an article in this publication? Over the years of various guest speaking or consulting contracts I have found sometimes someone looking at anything from ‘outside the box’ can critically analyse a task without any preconceived prejudice for the trade in question – sometimes it takes a crack to let the light in.

So I have spent some hours over the last month thinking about the application of wool in the aquatics and fisheries industry. Wool which obviously predominantly comes from sheep farmers in the UK.
Initially during my research I was shocked to learn about the amount of wool from sheared sheep that is discarded and the general view of a lot of farmers that the wool from sheep is a waste product. I was also amazed about the relationship between wool and the fisheries industry, I have learnt some interesting pieces of history that I would not otherwise know had I not been given the opportunity of writing in here.

One of the most profitable trout farms I know is paradoxically one of the smallest. An entrepreneur set it up from London who was fed up with city life; his father was a trout farmer and taught him the ropes as it were. Where his father was in the business for decades and was very traditional in his approach to fish farming, his methods worked and his business was profitable enough to make a living. His son after taking over the business used his knowledge of trout farming to produce high quality fish and crossed this over with experience in modern marketing. The result was he worked out a way to reduce the amount fish that needed to be produced and increase profits. The theory behind this is the less fish/less resources so fewer overheads. But this would mean having to sell fish for more money per head. What he did was instead of selling lots of trout at a low margin to supermarkets he figured ‘money is where the hassle is’ and began selling them directly to end users such as restaurants/directly to the consumer.  

I see parallels with this anecdote with various areas of farming. It seems the cunning successful farms have noticed and taken advantage of sidelines. So coming back to this waste wool I believe it is a ‘where there is muck there is brass’ kind of situation. The farmers taking advantage of selling off their wool or indeed processing their own wool on site have an economical advantage over their peers. In this age we live in of importing from China and a reduction in manufacturing in the UK, wool is a very important commodity. It is rich in heritage, it is home grown and better for the environment than synthetic materials.

Wool has an interesting history in fisheries. ’The Whitby wives’ for centuries used to knit their husbands jumpers out of wool. They would stitch their own unique signature pattern in the jumper. The reason behind this was because it was such an extremely dangerous trade to be a fisherman - unfortunately a lot of them used to die. The harsh weather conditions of the North Sea would bring unidentifiable battered bodies washed up on the beaches, so their wives would identify who was who by recognising the unique patterns in the woollen jumpers.

It is well documented that monks in the UK used rudimentary techniques to farm carp. Essentially the fish were grown on in ponds in monasteries, usually what we call an offline pond. They would use clay and straw to waterproof the soil. Because of the lack of electrical power in those days the process in which they farmed carp was ‘extensive’ as in a low number of fish compared to a larger surface area to volume ratio of fish. Increasing oxygen by using air pumps or water pumps came hundreds of years later which meant more fish could be held in water bodies.

The monks did however stumble upon mechanical and biological filtration. So offline ponds were basically a square or rectangle so the pond could be drained easily and the fish subsequently caught and harvested. The monasteries lucky enough to have what we know of today as oxbow ponds started building rudimentary filters. An oxbow pond is basically where a river runs through the middle of a field and part of the flow is diverted using weirs and dams. The water then flows through a pond and exits back into the river over a final weir. The advantage of this is there is constantly freshwater flowing through the farm ponds preventing the build up of nitrogenous waste and keeping oxygen levels higher. A disadvantage of having this flow through system is they used to get a build up of silt in the main ponds so would need draining and dredging. They came up with cunning techniques to prevent other fish species or indeed predatory invertebrates and fish getting into their lakes and at the same time preventing the build up of silt in the main ponds.

So the run up to the pond or ponds would have a silt trap system built first of a deep wider run so the water slows down and the heavier particulate matter would sink to the bottom of the trap. The final section would have a slimmer run where the flow would increase and therefor raise dissolved oxygen. Now this final area of water would be filtered using good old wool! Wool does not really change the pH of water (inert) and it has a fairly large surface area. So broadly speaking when I say mechanical and biological filtration it works like this:

Mechanical – simply trapping suspended solids
Biological – bacteria growing on the surface area of the media (in this case wool). The bacteria feed on nitrogenous wastes such as ammonia and nitrite which is toxic to fish if allowed to build up.

I doubt the monks knew they were creating a bacterial filter, this was probably inadvertent. Wool is still used to this day in some filters, there are better alternatives in modern filtration, but the basic principles are still the same and it is still a choice in LEDC’s (lower economically developed countries). I have seen wool being used in tilapia farms in Brazil. They use the wool to filter small particulate matter in closed loop tank systems. Wool also makes a great media for fish to lay eggs on and protect them from predators. Some fish are egg depositors and I have used a small clump of wool in the past so they can selectively place their eggs in the wool and guard them.
So writing this article has made me begin thinking about what I would do with wool if I were a sheep farmer. Assuming all was in place and I had a good flock and it was time to shear them. Logically speaking the wool to me would be a raw material and I would first decide where I would try and sell the wool; the same way a miner collecting minerals will decide if they are for jewellers or the technology industry.
So let’s say I have decided I would like the wool to be used in the clothing industry. Some farmers have the time and resources to process the wool themselves making the extra margins by cutting out the middlemen (as was the case in my latter anecdote about the trout farmer). Some farmers will simply sell the raw fleece to a mill. The wool will eventually get to a handspinner, rather than sending piles of fleece to them without considering the end result. I would work out the best cuts to send them so I can establish a working relationship over the years to come and possibly sell my fleece for more, as the quality is better.
I think my conclusion of scratching the surface in an industry foreign to me is no matter what business one is in, be it sheep farming, fish farming or a high street shop; Money is where the hassle is and as my grandparents used to tell me ‘where there is muck, there is brass’.