Following on from work with The Marine Ingredients Organisation (IFFO) investigating potential to increase global fishmeal and fish oil supplies from by-products, Julien Stevens, built on the work of Dr. Richard Newton, first in an MSc project and then with a follow up project to investigate how by-products from Scottish farmed salmon are utilised, and how value and efficiency could be added. Julien found that while most by-product was being utilised, it was often heterogeneous, both in terms of by-product fractions and with other species, such as white fish. This would then be reduced to fishmeal for sale in pet food, aquaculture diets of other species or to livestock. A range of strategies was found between salmon processors dependent partly on their size and location but also individual company logistics. Larger, more central processors were sometimes able to add more value by separation of by-products and identifying specific markets for them. Heads and trimmings could be sold for human consumption in foreign markets while other fractions such as skins could be sold for leather or collagen extraction in niche markets. Smaller more remote processors typically found it more difficult to separate by-products and tended to sell them mixed and at low value or have them removed at cost. It was found that adopting the best practice across the entire Scottish industry could not only improve the edible yield through direct and indirect consumption (through animal feeds) but would improve the value of by-products several fold, adding around 5% value to the Scottish salmon industry. Full findings will be published in a forthcoming article.
2015 UK Salmon By-product Totals. Based on data collected from participating primary processors, and relevant industry data on by-product fraction percentages (Stevens 2016 MSc thesis)