Burgons, a leading crab processor, is looking at ways to add value to the shell waste produced at its factory in the small fishing town of Eyemouth, on the south-east coast of Scotland. It also needs to reduce the cost of disposing of the waste.
With a meat yield of about 40% the company accumulates 600kg of shell waste from every tonne of crab processed. Much of this material currently has to go to land fill.
“We process over 1,400 tonnes of crab and crab components per year,’ says Grahame Sinclair, sales director, “and are sending 350 to 400 tonnes of shell waste to land fill. Our waste disposal costs last year were heading towards £40,000 which is a huge cost to a small business such as ours.”
Burgons is considering two ways of utilising its crab shell waste. It has conducted a six month trial with Glasgow University to develop a bait product which would attract whelks into pots. There is a considerable whelk fishery around the British Isles and a lucrative export market exists for whelk meat in South East Asia.
It is also considering a project whereby dried crab shell is shipped to China for glucosamine and chitin extraction, both of which have a number of dietary, medical and other applications.
The bait project is the more advanced, and Burgons has carried out sea trials off the English and Scottish coasts. However, in the trials, it was discovered that cooked crab waste was not nearly as effective for whelk bait as raw crab. (All the crab entering the Burgons factory is cooked before being further processed.)
The next step, therefore, was to combine the cooked crab shell with raw waste from the Scottish nephrops (langoustine) fishery and the resultant mixture was much more successful in attracting whelks. Scallop or mussel waste could also be used, Mr Sinclair says, and further sea trials are to be carried out using these products.
One problem is to prevent the bait from dissolving too quickly once inside the pot so the ingredients have to be bound together in some way. Burgons is also seeking a biodegradable ‘container’ for the bait such as a netting tube.
For trial purposes the bait is made by hand, but once its manufacture becomes a commercial proposition then the different functions will be mechanised. For example a bowl chopper could be used to bind the ingredients together and an extrusion machine could ‘fill’ the bait mixture into a netting tube.
Burgons was put in touch with Glasgow University by Interface - The Knowledge connection for Business, a Scottish agency funded by the EU, Scottish Enterprise and the Scottish government.
Seafood Scotland also provided funding for the bait development work through its Value Added Programme which has been designed to help Scottish seafood companies develop their businesses.
Mr Sinclair estimates that the demand for bait for catching whelks is about 2,000 tonnes per year. However, the bait Burgons has developed so far will also attract lobster, velvet crab and langoustine. So material that now has to be dumped into the ground could well turn out to be a valuable product in its own right.
