Omar Peñarubia, 26 April 2021

Fish is a highly perishable food that begins to spoil as soon as it is caught, perhaps even before it is taken out of the water. Therefore, particular care is required during harvesting and all along the supply chain to preserve nutritional attributes,  prevent contamination, minimize loss and waste, and to deliver high quality fish product.

Different processing methods, such as salting, drying and smoking, are used to increase shelf life and diversify products across continents, regions and countries Processing helps reduce food loss and waste, thus reducing the pressure on the fisheries resources, and fostering the sustainability of the sector.

Processing often results in quantities of by-products, such as heads, bones, guts, and shells. These by-products represent between 30 and 70 percent of the whole fish and provide a good source of macro- and micronutrients yet they often go un-utilized and end up as waste. To minimize food loss and waste in the fish value chains and, at the same time, improve fish waste management strategies, several methods can be used to convert by-products into value added products: animal feed ingredients (fishmeal and fish oil), biofuel and biogas, dietetic products (chitosan), pharmaceuticals (omega-3 oils) and constituents in other industrial processes. Other popular products include fish leather, fish silage and fertilizer.

Fishmeal and fish oil can be produced from whole fish, fish trimmings or other fish processing by-products. It is estimated that 25 to 35 percent of the growing share of fishmeal and fish oil is produced from the by-products of fish processing, which previously were often discarded or used as direct feed, to make silage or in fertilizers.

Fish silage is produced from the whole fish or parts of it, to which acids, enzymes or lactic acid-producing bacteria are added. The fish silage process transforms fish waste into a liquid mix of hydrolysed proteins, lipids, minerals and other nutrients, easily digestible by both terrestrial and aquatic animals. Fish silage can be a viable alternative to fish meal as an abundant animal protein source for the manufacture of rations for domestic animals. Furthermore, it can also be an excellent fertilizer.

FAO recently published feasibility studies on the production and utilization of fish silage in Barbados and Saint Kitts and Nevis and in Bangladesh, Philippines and Thailand. In Barbados, the majority of fish waste and by-products are disposed of in landfill. To address this, multiple supply chain scenarios are developed for the production of fish silage. In Saint Kitts and Nevis, where there is likely a high potential demand for feed additives, various supply chain configurations could be used to produce fish silage. In Bangladesh, the prospect of fish silage production constitutes a promising new development for animal feed production, given that the availability of waste materials from seafood processors – and the demand from feed millers – favours the conditions for silage production. In the Philippines, fish silage technology is seen as an efficient way to maximize the utilization of waste. This would be especially useful in coastal areas of the country where there are currently no existing waste utilization facilities. In Thailand, small communities have shown interest in fish silage production for animal feed that is of higher value than fertilizer.

The utilization of fish by-products is also linked to Blue Fashion. This is an innovative way to support fishing communities while reducing waste and offering sustainable alternatives to the fashion industry. Blue Fashion aims to create sustainable fashion items from marine raw materials and by-products. These are bio-alternatives to traditional fashion industry products and include clothing, purses and shoes made from fish skin leather, fish scales and seaweed fabric.  

The benefits from fish processing not only results in a more stable product shelf-life and can reduce fish loss, but fish processing also has the potential to utilize by-products to produce value-added products and convert what was once waste into both economic and environmental gains.  

Find more information and resources on fish processing here.