The Untapped Potential of Fish Waste and By-products

The increasing global focus on nutritious diets has driven rapid growth in the fishing industry. While this boom in fish production reflects the growing demand for fish as a nutritious food source, it also underscores a pressing challenge: the generation of fish waste and its environmental implications.

The Scale of the Fish Waste Problem

Fish production has grown significantly over the last decades, rising from 19 million tonnes in 1950 to a record-breaking 185 million tonnes in 2022 representing an average annual increase of 3.2% (FAO, 2024). However, this rapid growth in fish production has also led to a sharp rise in fish waste worldwide. In fact, the fishing sector accounts for two-thirds of all fish waste globally. Post-catch losses, which occur throughout the distribution chain—from landing to consumption—represent a significant economic and environmental concern where large amounts of fish are lost or discarded due to mishandling, processing inefficiencies, or lack of marketability (Coppola et al., 2021).

Fish Waste vs. Fish By-Products: A Key Distinction

It is important to distinguish between "fish waste" and "fish by-products." Fish waste typically refers to small or damaged fish with low market value, while fish by-products include parts such as skin, fins, scales, viscera, and bones. Together, these can make up 30% to 70% of a fish's total weight (Caruso et al., 2020).

Fish processing generates significant amounts of both waste and by-products, depending on the species and the processing method (e.g., gutting, scaling, or filleting). Common discards include muscle trimmings (15–20%), skin and fins (1–3%), bones (9–15%), heads (9–12%), viscera (12–18%), and scales (5%) (Martínez-Alvarez et al., 2015).

Unlike fish waste, which is generally discarded, fish by-products are often repurposed to create value-added products. These by-products contain nutritionally valuable components, such as proteins, fatty acids, and minerals, with compositions similar to those found in edible fish fillets (Caruso et al., 2020).

Harnessing the Nutritional and Economic Potential of Fish By-Products

Fish by-products, which were once discarded as waste, are now increasingly being repurposed into valuable food and non-food products. In 2022, by-products accounted for 34 percent and 53 percent of the total production of fishmeal and fish oil, respectively (FAO, 2024).

Beyond direct human consumption or fishmeal and fish oil production, fish by-products are increasingly recognized for their high content of bio-compounds such as collagen, peptides, chitin, polyunsaturated fatty acids (PUFAs), enzymes, and minerals (Coppola et al., 2021). These compounds have immense potential for use in biotechnological and pharmaceutical applications, which command high market value.

For example, collagen derived from fish skin is used in cosmetics and nutraceuticals, while peptides and enzymes have applications in food preservation and medical research. This shift towards high-value applications not only maximizes the use of fish resources but also contributes to a circular economy.

A Sustainable Path Forward

To mitigate the environmental impact of fish waste and unlock its full potential, several strategies must be prioritized. For example, by improving processing techniques that reduce waste during fish processing, developing and improving efficient methods to convert waste into high-value products, encouraging industries to adopt sustainable practices through incentives and regulations, and highlighting the economic and nutritional benefits of fish by-products.

In VALORISH, we are working on the valorization of fish waste and by-products through a sustainable cascade biorefinery approach, transforming these underutilized resources into high-value bioproducts under a computationally-assisted methodology. By transforming fish waste into valuable resources, we can address environmental concerns, support economic growth, and foster sustainability in the fishing industry. The journey from waste to wealth is not only possible but essential for a thriving, circular economy.

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References

Coppola, D., Lauritano, C., Palma Esposito, F., Riccio, G., Rizzo, C., & de Pascale, D. (2021). Fish waste: From problem to valuable resource. Marine Drugs, 19(2), 116. https://doi.org/10.3390/md19020116

Caruso, G., Floris, R., Serangeli, C., & Di Paola, L. (2020). Fishery wastes as a yet undiscovered treasure from the sea: Biomolecules sources, extraction methods, and valorization. Marine Drugs, 18(12), 622.

FAO. (2024). The State of World Fisheries and Aquaculture 2024 – Blue Transformation in action. Rome.

Martínez-Alvarez, O.; Chamorro, S.; Brenes, A. (2015) Protein hydrolysates from animal processing by-products as a source of bioactive molecules with interest in animal feeding: A review. Food Research International, 73, 204–212