THE Scottish salmon farming industry could make better use of by-products, adding 5.5 per cent value to the sector, researchers have found.
Though generally well utilised, total by-product value output could be improved by 803 per cent (£23.7 million), based on 2015 figures, according to a recent study.
Led by Julien Stevens, researchers from the University of Stirling’s Institute of Aquaculture and University of Massachusetts, Boston, have published research funded by IFFO, the Marine Ingredients Organisation.
The research investigated how value could be added to aquaculture through better utilisation of by-products, by maximising edible yields and better separation at the processing stage, looking at the Scottish salmon farming industry as a case study.
The terrestrial livestock processing industry has long been able to separate by-products to maximise value and efficient utilisation, and this research 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.
Far from being ‘waste’, marine by-products are a potentially important resource, being known to contain valuable nutrients such as minerals, vitamins, protein and lipid fractions (especially important long chain omega-3 fatty acids) which can support further processing into a range of products and markets.
By exploiting all high value by-product types (heads, frames, trimmings and belly flaps) for existing domestic and export food markets, the authors demonstrated the potential to add 5.5 per cent value to the salmon industry.
Directing 77 per cent of the annual whole fish production towards human consumption results in 132,171 tonnes of food.
The remaining by-products can then be utilised in the production of fishmeal and fish oil, and subsequently used in aquafeed for farm raised marine species.
The authors also commented on how current Fish in: Fish out (FI:FO) models do not adequately take into account how finfish are utilised.
IFFO’s Dr Neil Auchterlonie (pictured) noted that ‘current research highlights that FI:FO calculations tend to be simplistic, nether taking into account the nutritional contributions from fishmeal and fish oil beyond protein and energy, nor do they account for the end product other than the edible portion.
‘FI:FO ratios have therefore tended to underestimate the contributions from fishmeal and fish oil.’
Stevens 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.’
Read the full paper here: The rise of aquaculture by-products: Increasing food production, value, and sustainability through strategic utilisation