Innovation in aquaculture can enable the reduction of fish waste and its upcycling into protein, marine Omega-3 fatty acids and various micronutrients. A study by the University of Stirling (Malcorps et al., 2021)-funded by the GAIN research project (EU, Horizon 2020)-examines the characteristics of some of Europe’s most common aquaculture fish with a view to the virtuous recovery of their byproducts. (1)
1) Fish, consumption and food security needs . Foreword
Demand for seafood products in Europe is steadily increasing, data from EUMOFA(European Market Observatory for Fisheries and Aquaculture Products) show. In 2021, spending on these products grew by 7 percent to reach a per capita consumption of about 23 kg/year. (2) Fish stocks on the other hand are shrinking, due to IUU(Illegal, Unreported and Unregulated fishing) and overfishing as well as pollution, climate change and other stressors on aquatic populations. (3)
Biological and regenerative aquaculture-supplemented with algae, microalgae, and shellfish-is the only chance, as noted above, to ensure humans adequate supplies of the nutrients and micronutrients offered by fish species (4,5,6,7). In the medium term, the use of cell agriculture to reproduce cells of various fish species is also on the horizon, but the accessibility of this type of alt-fish in Low-Middle Income Countries (LMICs) is likely to take additional years. (8)
2) Fish, fish waste and food waste.
The fish is vastly underutilized due to a significant share of fish waste that is equally rich in nutrients and micronutrients but to date, beyond the rare hypothesis of food-grade fishmeal production, (9) is either destined for feed production or disposed of as waste.
Research is therefore directed toward the development of efficient technologies forupcycling fishery and aquaculture wastes into food, nutraceutical and cosmetic ingredients. (10) The EcoeFISHent project, funded by the EU in Horizon Europe, begins with, among other things, the concentration of fish waste from industry and retail. (11)
3) Nutritive value of fish waste.
Scottish researchers (Malcorps et al., 2021) studied the characteristics of the most common fish in European aquaculture. Atlantic salmon, sea bass, sea bream, turbot, and common carp (the only freshwater fish).
Fillets account for an average of 56 percent of the mass but the edible part, even before considering the extraction of nutrients and micronutrients with innovative technologies, reaches 70 percent.
The waste is characterized by its richness in omega-3 fatty acids, eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), vitamins D and B12, iodine, selenium and other minerals.
4) Protein and fatty acids
Proteins in aquaculture fish wastes were found in a significant proportion in the skin (20 percent the average, 23.4 percent that of turbot in the upper end), heads (13.1-20.2 percent), frames (16.8-19.4 percent), trimmings (lowest value 15 percent for common carp) and viscera (11.1-17.2 percent).
Fatty acids were found to be present to a greater extent in European sea bass (7.02 g/100 g), Atlantic salmon viscera (4.44 g/100 g) and common carp (4.07 g/100 g). Carp skin stands out for saturated fat content (7.92 g/100 g), Atlantic salmon viscera and offcuts, and European sea bass for polyunsaturated fatty acids (PUFAs).
Omega-3s, EPA + DHA, were detected most significantly in the viscera of sea bass and heads, clippings, skin of Atlantic salmon. Next, in the turbot bones. However, among the aquaculture fish species examined, common carp is the fish that shows the lowest values of Omega-3 fatty acids. With variations always related to the feeds used.
5) How to reduce foodloss (food loss)
The study under review (Malcorps et al., 2021) also proposes some solutions to reduce food losses at the processing stage of seafood products(food loss), to increase the sustainability of the processes in a circular economy logic.
5.1) Optimizing yields.
Less selective processing than filleting can reduce fish waste and increase the availability of edible parts significantly (30 to 64 percent in turbot, 56 to 70 percent for salmon).
5.2) Upcycling.
The parts now considered fish waste should be recovered for human food, as is already done to a large extent in the craft tradition and in the industrial processing of land animal carcasses.
6) Iceland Ocean Cluster, ‘100% Fish‘
‘100% Fish‘ is the project developed by Iceland Ocean Cluster to reduce waste and thus increase the profitability of fisheries and aquaculture. Over the past 30 years, the use of fish by-products in Iceland has increased 30-fold, to the point that local cod producers now use up to 80 percent of the raw material (compared with an average of 50 percent, in the U.S. and Northern Europe).
Innovative technologies enable both the reduction andupcycling of fish waste into a variety of ingredients and food products. As well as in bioactive compounds (peptides, collagen, chitin and chitosan, enzymes and biopolymers) for nutraceuticals, cosmetics and medicine. Fish in Iceland are valued in every way, even as hides. (12)
7) Upcycling fish waste, from Norway to Vietnam.
Norway was one of the first countries to recognize fish by-products as a resource, with laws encouraging their use (for fish oil, feed and fertilizer) as early as 1639. Currently, Norway handles more than 650,000 tons of fish by-products each year, and the Atlantic salmon industry uses about 90 percent of its by-products.
Vietnam in turn carefully separates and directs pangasius fish waste to specific industries to reduce waste and create added value. And globally, there is increasing interest in adopting strategies for other species of fish, crustaceans and mollusks.
8) Scotland, the case-study of strategic use of fish waste from aquaculture salmon
Previous research from the University of Sterling (Stevens et al., 2018)-through exploratory case-study-based scenarios-identifies that Scotland could increase food production from waste Atlantic salmon aquaculture food from fish farming by more than 60 percent.
The case-study projects a significant increase in by-product revenues (+803%) and industry profits (+5%), without the need to install new cages or use other marine resources. Orienting the aquaculture industry toward a new era of production and processing, where to obtain a diverse range of products from a single species. (13)
9) Technological challenges
‘Strategies for processing and thus using by-products depend on the overall food environment, including consumption preferences that can vary widely across Europe, from whole fish to various processed forms of different species.
In addition, fish and seafood may contain chemical contaminants with related health implications and require investment in HACCP and decontamination to meet food quality requirements. (14) These attentions are obviously also required for the reuse of fish waste as feed ingredients (e.g., protein meals and oils).
10) Interim Conclusions
‘The analysis under review highlighted the different nutritional profiles of the by-product fractions, indicating that separation of fish waste could offer better opportunities to maximize value addition and nutritional efficiency.
This could create incentives for processing and utilization, allowing the aquaculture industry to diversify its products and use marine resources more efficiently.
Consequently, increasing aquaculture production in terms of volume and value without using more resources is a perfect example of eco-intensification‘ (Malcorps et al., 2021).
Dario Dongo and Alessandra Mei
Notes
(1) W. Malcorps, R. W. Newton, M. Sprague, B. D. Glencross, D. C. Little (2021). Nutritional characterisation of European aquaculture processing by-products to facilitate strategic utilization. Front. Sustain. Food Syst., 20.10.21. Sec. Water-Smart Food Production, Vol. 5 – 2021. https://www.frontiersin.org/articles/10.3389/fsufs.2021.720595/full
(2) EUMOFA (2022). The EUfish market. https://www.eumofa.eu/documents/20178/521182/EFM2022_EN.pdf/5dbc9b7d-b87c-a897-5a3f-723b369fab08?t=1669215787975 The EU market overview https://www.eumofa.eu/the-eu-market
(3) Dario Dongo. Protection of fisheries and marine ecosystems, EU (in)action plan. GIFT (Great Italian Food Trade). 26.12.21
(4) Marta Strinati, Dario Dongo. Organic aquaculture, the last chance. GIFT (Great Italian Food Trade). 25.2.19
(5) Marta Strinati. Algae and shellfish, aquaculture that regenerates the seas. GIFT (Great Italian Food Trade). 10.11.19
(6) Giulia Paganini, Dario Dongo. 2022, international year of artisanal fisheries and aquaculture. GIFT (Great Italian Food Trade). 3.1.22
(7) Dario Dongo, Alessandra Mei. Seafood Alg-ternative and Alt-Fish, microalgae in plant-based seafood products. GIFT (Great Italian Food Trade). 12.4.23
(8) Dario Dongo. Fish from cell cultures, the new biotech frontier lands in Europe. GIFT (Great Italian Food Trade). 21.10.21
(9) Dario Dongo. Fishmeal, a huge untapped potential. GIFT (Great Italian Food Trade). 9.12.22
(10) Upcycling. Omega-3s from the waste of the fish supply chain. GIFT (Great Italian Food Trade). 29.10.21
(11) Dario Dongo, Andrea Adelmo Della Penna. EcoeFISHent, upcycling and blue economy in the fish supply chain. The EU research project. GIFT (Great Italian Food Trade). 18.10.21
(12) 100% Fish. https://www.sjavarklasinn.is/en/100-fish/Iceland Ocean Cluster
(13) Stevens, J. R., Newton, R. W., Tlusty, M., and Little, D. C. (2018). The rise of aquaculture by-products: increasing food production, value, and sustainability through strategic utilization. Mar. Policy 90, 115-124. doi: http://dx.doi.org/10.1016/j.marpol.2017.12.027
(14) Thomsen ST, Assunção R, Afonso C, Boué G, Cardoso C, Cubadda F, Garre A, Kruisselbrink JW, Mantovani A, Pitter JG, Poulsen M, Verhagen H, Ververis E, Voet HV, Watzl B, Pires SM (2022). Human health risk-benefit assessment of fish and other seafood: a scoping review. Crit Rev Food Sci Nutr. 2022;62(27):7479-7502. doi: 10.1080/10408398.2021.1915240