The Scottish salmon industry could receive a boost of more than £23 million if it better utilises fish by-products, according to a new University of Stirling study.
Researchers at Stirling’s Institute of Aquaculture and the University of Massachusetts found that the total value of by-products could increase by 803 per cent if salmon farms maximise edible yields and introduce better separation at the processing stage.
It would add 5.5 per cent to the salmon industry in Scotland, the research found.
Lead author Julien Stevens, pictured right, of the Institute of Aquaculture, said: “We hope this research facilitates improvements, there is a need for further infrastructure investment and policy support to incentivise resource efficiency, along with greater transparency on the current uses of by-products within the sector.”
The terrestrial livestock processing industry has long been able to separate by-products to maximise value and efficient utilisation. The new study – funded by IFFO, the Marine Ingredients Organisation – sought to identify the best markets for salmon processing by-products in the same way.
For finfish, by-products typically include trimmings, skins, heads, frames (bones with attached flesh), viscera (guts) and blood. They are a potentially important resource, known to contain valuable nutrients, such as minerals, vitamins, protein and lipid fractions (long chain omega-3 fatty acids), which can support further processing into a range of products.
The scientists used figures from 2015 and found that, by exploiting all high value by-product types for existing domestic and export food markets, there was the potential for a total increase of 803 per cent, or £23.7 million.
By combining primary products (54 per cent yield), with the maximum potential by-product food yield (around 23 per cent), it results in 132,171 tonnes of food.
The remaining by-products, minus blood water (4.3 per cent) are then utilised in the important production of fishmeal and fish oil, and subsequently used in aquafeed for farm raised marine species. In this example, accounting for that material in feed for European seabass and gilthead seabream, would result in 148,691 tonnes of total edible yield compared to the original production of 92,081 tonnes of salmon.
Stirling’s Dr Richard Newton and Professor Dave Little also worked on the study, alongside Michael Tlusty, of the School for the Environment at the University of Massachusetts.
The research, The rise of aquaculture by-products: Increasing food production, value, and sustainability through strategic utilisation, is published in Marine Policy.