According to our former MatureDevelopment colleague Björn Kok his new calculation method shows that 1 kilo of wild fish can yield up to 3 or 4 kilos of farmed fish.
Fish farms were once considered to be one of the solutions for sustainably feeding the world. Until research showed that there was much more feed required in producing this fish than the amount of fish coming out of it. Yet according to the Utrecht Master’s student Björn Kok this has proven not to be the case. It is exactly the other way around he asserts. He calculated with his new measuring method that only 1 kilo of fish goes into production and 3 to 4 kilos of fish come out.
Farmed fish feed includes fishmeal as a source of protein and fish oil as a source of omega 3 fatty acids. Fish meal and fish oil are made from wild fish that are caught, often anchovies. How many kilos of wild fish are needed to produce one kilo of farmed fish is calculated using the so-called FIFO ratio: Fish In – Fish Out. Several methods are used to calculate the FIFO ratio.
Björn’s new method, eFIFO, considers the shortcomings of other methods. “In such a way as to do justice to the socioeconomic motives behind catching fish for the production of fish meal and fish oil. It is a consistent and accurate way to calculate exactly how much wild fish you actually need to feed your farmed fish“ he states.
In addition, eFIFO considers the use of by-products: fish heads, bones, fins. “Everything except the fillets. Approximately 30% of fish meal and fish oil is produced from by-products. Other methods see this as ‘free raw material’, and underestimate the FIFO ratio. Sustainability labels and certificates still use the old methods for their certification. They also set their standards based on old FIFO methods, but if the underlying calculation is inaccurate, it is difficult to set the targets correctly”.
Salmon and tilapia most sustainable fish to eat
Salmon is not the only species of fish that Björn has studied. “If you look purely at kilos, carp and tilapia are the most sustainable fish to eat. Pangasius is also doing well. But all three of these fish have a completely different – as in lower – nutritional value than salmon.”
“One of the older methods,” Björn continues, “calculates fish meal and fish oil separately. For example, farmed salmon need a relatively large amount of fish oil compared to fish meal. In order to meet the demand for fish oil, more wild fish must be caught. But the fish meal that is produced at the same time as the fish oil is ignored in these calculations.”