Fish Waste Composition and Classification

Globally, food waste is a menacing issue, which is primely focused on Sustainable Development Goal (SDG) Target 12.3, aiming to cut down wastage by 2030. Thirty-five percent of the fish caught in fisheries and aquaculture are thrown away as fish waste and by-products. Fish processing waste accounts for about 70% of them, which can be turned into a valuable resource through a circular bioeconomy. The utilization of fish waste can also assuage the pressure on the fishery’s resources and nurture the sustainability of the realm. The valorization of fish waste and by-products is gaining significant attention as a source of nutrition besides being used as fodder or thrown away as waste. The by-products of fish typically include heads (9–12% of the total weight of the fish), bones (9–15%), scales (around 5%), viscera (12–18%), and skin (1–3%). Indeed, fish waste is justified to be a good source of protein (58% dry matter), fat (19%), and minerals. The potential techniques are being utilized to treat fish waste and recover valuable bioactive compounds. Therefore, this chapter underlines the enormous power of fish waste and its by-products.