Salmon farming is among the most efficient ways of producing protein-rich food.
Feed conversion ratio (FCR) is a helpful way of describing efficiency in terms of how much feed is required to produce 1 kg of fish. For salmon, the FCR is around 1.2. This means that to produce 1 kg of salmon, you need around 1.2 kg of feed. Although not directly comparable, due to differences in the composition and energy density of the feed, other food industries such as poultry, pig, sheep and cattle farming have feed conversion ratios of around two, three, eight and eight respectively.
The low feed conversion ratio of salmon farming is explained partly by the following factors:
• Salmon feed has a high energy content and is highly digestible
• Salmon are very efficient at utilising the protein in the feed and much more so than farmed animals. The protein retention, which is a measure of protein utilisation, can be as high as 45% in salmon, while corresponding figures for poultry and pig are 18 and 13% respectively. The high protein retention gives salmon farming an ecological advantage compared to production of other meats, as more of the proteins in the feed are converted into meat
• As salmon live suspended in water, they use very little energy to support themselves compared to land animals
• Salmon also need less energy to maintain bodily functions as their body temperature is always close to the ambient temperature, normally between 6 and 16 degrees Celsius