Is salmon feed sustainable? Do farmed salmon eat wild fish?

To prevent overfishing, the fishmeal and fish oil from wild fish in fish feed have been partly replaced by vegetable ingredients.

Research has made it possible to reduce the amount of fishmeal and fish oil without compromising fish welfare or the quality of the salmon. Photo: Marius Fiskum/Norwegian Seafood Council

Fishmeal and fish oil, the main ingredients in salmon feed, are classified as renewable resources. They are made from fish scrapings and fish that are not used for human consumption, and only species that are not exposed to overfishing are used.  Fish farming is a rapidly growing industry, and the aquaculture industry has a responsibility to ensure that the resources are used in a sustainable manner. Production of omega-3 supplements has increased the demand for marine products, but there are not enough marine raw materials to meet the growing demand.


Wild fish from regulated fisheries

The aquaculture industry in Norway does not use fishmeal or fish oils made from fish on the World Conservation Union's (IUCN) list of endangered species.  To ensure that the wild fish come from regulated fisheries, fish feed companies monitor their suppliers through tracking documents and audits. The size of wild fish stocks may vary from year to year for many reasons – not just because of fishing. To prevent overfishing, it is crucial that the use of wild fish in aquaculture feed is regulated. In Norway, about 90 percent of the wild fish used in fishmeal and fish oil comes from regulated fisheries. The most commonly used species are herring, blue whiting, capelin, sprat and anchovy. Herring is only used when the catch is greater than the demand from the consumer market. From the southern hemisphere, mainly anchovies are used.


Replacing wild fish with vegetable ingredients

Despite the tremendous growth of Norwegian aquaculture, the industry has not increased the usage of wild fish. The reason is that fish feed manufacturers have partly replaced marine raw materials with vegetable ingredients. Research has made it possible to reduce the amount of fishmeal and fish oil without compromising fish welfare or the quality of the salmon. In the 1990s, 90 percent of Norwegian salmon feed consisted of fishmeal and fish oil. Today, these two products constitute only around 30 percent of the feed, which is still enough to make sure the salmon have sufficient levels of the omega-3 fatty acids EPA and DHA. The rest of the feed is made up of sustainably produced vegetable ingredients like soy [insert internal link]. The salmon industry uses sensors and underwater cameras to reduce feed waste, i.e. feed that slips through the cage without being eaten. Today it is also easier to make use of scrapings and by-products from fish production.


Efficient feed utilization

Efficient feed utilization is crucial to ensure that the aquaculture industry is sustainable. The fish-in/fish-out ratio (FIFO) is a way to measure the extent to which farmed salmon utilize the feed. FIFO indicates how much wild fish, in the form of fishmeal and fish oil, is needed to produce one kilogram of farmed salmon. The FIFO ratio for fish oil dropped from 7.2 in 1990 to 1.7 in 2013, while the FIFO ratio for fishmeal went from 4.4 to 1.0 in the same period. The following factors affect the FIFO rate: how many kilograms of fishmeal and fish oil that can be derived from wild fish, how much of this that is used in the feed, and how oily the wild fish is. According to studies from NIFES, it is possible to produce one kilogram of salmon with less than one kilogram of wild fish.

Another way to measure feed utilization of farmed salmon is by checking how much of the nutrients in the feed is carried over to the salmon. According to surveys from 2012, 24 percent of the energy and 27 percent of the proteins transfer to the edible part of the salmon. Compared to chicken and pork, farmed salmon retains more energy, protein and phosphorus from the feed. This makes salmon the most resource-efficient meat produced in Norway.


Useful links:

The International Union for Conservation of Nature (IUCN) 

Institute of Marine Research: Is it sustainable to use wild fish for aquaculture feed? (in Norwegian only) 

Utilisation of feed resources in production of Atlantic salmon in Norway (scientific article)

Nofima – Use of raw materials and efficiency of Norwegian salmon farming: