Fish by-products show potential for sustainability in new study
Researchers from the University of Stirling Institute of Aquaculture the by-products found – such as fish heads, carcasses, trimmings, skin and organs – are an underutilized resource that could support the sustainable growth of the European aquaculture sector.
As a member of Intensification of green aquaculture in Europe (GAIN) Wesley Malcorps, a doctoral researcher at Stirling, found that much of the commonly farmed species – Atlantic salmon, European sea bass, sea bream, common carp and turbot – were routinely wasted in industrial and domestic processing.
Mr Malcorps said: “Although fish by-products may not sound appetizing, they are full of benefits and can be used for many purposes, including in the food supply and dietary supplements. Our results show that a significantly higher total meat yield (64 to 77 percent) can be obtained if the fish is fully processed, compared to fillet only (30 to 56 percent), as is often the case. .
“Heads, frames and toppings of all species have the potential to increase the food supply, in soups or processed foods, such as fish fingers, sauces and fish cakes. They could also be made into food and nutraceutical extracts – such as protein powders, fish oil, and collagen supplements – potentially producing higher economic value.
“Organs can be used in animal feed, just like skin, because of its high protein content and low ash content. With their high level of valuable omega-3 fatty acids, feeding livestock as a by-product would also contribute to nutrition in the human food chain, and the by-products can also be used in pet foods.
Importantly, the current 33 percent of by-products used in fish feed – such as fishmeal, fish oil, and protein hydrolyzate – could be increased, which could reduce considerably the environmental impact of aquaculture.
Mr Malcorps said: “European aquaculture depends on food imported from marine and terrestrial systems, such as fishmeal, oil and soybeans, especially for carnivorous species such as salmon. Substituting plants for marine ingredients only shifts the impact from the sea to the land, and also risks compromising the health and welfare of the farm animal.
Finally, the study showed potential industrial uses of the by-products, in cosmetics, pharmaceuticals and packaging.
“Fish skin offers potential for collagen and gelatin extraction, as an alternative source to cattle or pigs,” added Mr. Malcorps.
Fish skin can also be used as fish leather for the fashion industry.