While whitefish trimmings are valuable for their oil and fishmeal, the use of salmon processing leftovers has been largely ignored, partly due to certification issues.
University of Stirling researchers at the Institute of Aquaculture say that underutilization ignores a potential reward worth GBP 23 million in value to the Scottish salmon industry.
In their report, The Rise of Aquaculture By-Products: Increasing food production, value and sustainability through strategic utilization, the researchers insist there was food-export value to be had that would add “803 percent” more value to the industry, “if salmon farmers maximise edible yields and introduce better separation at the processing stage”.
“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,” stated lead author, Julien Stevens, of the Aquaculture Institute.
For finfish, “by-products” can be trimmings, skins, heads, bones, guts and blood that contain minerals, vitamins, protein and omega-3 fatty acids good enough to process into a range of products.
By combining primary products (54 percent yield), with the maximum potential by-product food yield (around 23 percent), it results in 132,171 tonnes of food, the researchers wrote. The rest, minus blood water, could become fishmeal and fish oil “used in aquafeed for farm raised marine species”.
Critics, however, suggest fishmeal and fish oil destined for farmed-fish not contain traces of farmed fish in order to break a perpetual cycle that could contain whatever contaminants might have build up over time, and to better mimic what salmon eat at sea (they would recommend aquafeed from other sources).
Fish oil and meal from farmed salmon, however, is a worthwhile commercial target for the valuable ingredients in the trimmings, even as “human edible yield”, if highly processed.