Turning processing waste into profit

Burgons of Eyemouth, one of Europe's leading crab companies, is assessing the effectiveness of bait products manufactured from shell waste from its processing plant on the southeast coast of Scotland. It is also considering a project to ship dried crab shells to a plant in China for the extraction of glucosamine and chitin.

Burgons, a family-owned firm that started out as a herring company in the early 1900s, has been processing European brown crab (Cancer pagurus) for more than 30 years.

"We process over 1,400 tons of crab and crab components per year," said Grahame Sinclair, the company's sales director, "and produce a range of 25 different crab products for retail, foodservice and for value added processing."

However, with a meat yield of approximately 40 percent, the company accumulates 600 kilograms of shell waste material from every ton of crab processed. Currently, much of this material goes to land fills at a significant cost to the company.

Unfortunately there are restrictions in disposing of this shell waste back to sea, which, ironically, has shown in the past to attract cod and other whitefish species, and which could go some way to improving inshore fisheries

"We are sending 350 to 400 tons of shell waste annually to land fill. Our waste disposal costs last year were heading towards GBP 40,000 (USD 65,550), which is a huge cost for a small business such as ours," said Sinclair.

For the past six months, Burgons has been working with scientists at Glasgow University to develop a bait from its cooked shell waste that would attract whelks into catching pots. There is a considerable fishery for whelks around the coasts of the UK and Ireland and a very lucrative export market for whelk meat in Southeast Asia.

"The existing market for this type of bait is considerable," said Sinclair. "There is a requirement for about 2,000 tonnes of bait per year for catching whelks."

Sea trials with prototype products have been carried out off the coast in different parts of the UK mainland. However, it was found that cooked crab waste - all of the crabs entering the factory are cooked whole before being further processed -was not as successful at attracting whelks as raw crab. Mixing cooked crab waste with raw nephrops (langoustine) waste was much more effective, said Sinclair. "Scallop or mussel waste could also be used," he explained.

There is still work to be done on the bait, added Sinclair. The ingredients have to be bound in some way to prevent the bait from dissolving too quickly once inside the pots, and Burgons is looking for a biodegradable "container" for the bait such as a netting tube that will disintegrate in seawater.

The company is therefore seeking more funding to extend its cooperation with Glasgow University for further trials. (Various Scottish organizations such as Seafood Scotland and Scottish Enterprise have been funding the development work up to now.)

Even in its current form the crab waste bait will attract lobsters and velvet crabs as well as whelks, so there are many potential uses, said Sinclair.

Meanwhile, the project regarding crab shell being dried and shipped to China for glucosamine and chitin extraction is in its early stages of development, with Burgons partnering with another Scottish business in setting up a new processing unit. Glucosamine and chitin have many uses in dietary, medical, optical and other industrial products, so this project could also be of significant financial benefit to Burgons when it gets underway.

So what was once considered to be waste material of no value, and which is costly to dispose of, could well turn out to be a very valued product in its own right.