This piece was first published in the International Aquafeed Magazine, November 2020 edition

In fish farming at an industrial scale, salmon farming is probably the most advanced and sophisticated of all farmed species. In 2019 the total consumption of farmed Atlantic salmon was around 2.3 million tonnes.

But farming salmon is far from being straightforward. Fish health management plans are essential and feed ingredients play an important role in securing healthy growth in the farms. Fish farming companies are well aware that the integrity of salmon skin, intestine and gill tissues is vital for the health of the fish, for its growth and for its further consumption by humans. The salmon farming industry is investing heavily in research and innovation to improve fish health, from  protecting sea pens with anti-sea lice shields and deploying cleaner fish (such as wrasse and lumpsuckers) which graze on sea lice reducing the need for veterinary medicine, to extending the growth phase in freshwater via Recirculation Aquaculture System (RAS), thereby reducing exposure to the sea lice challenge at sea.

Nutrition is well-established as a key aspect of health and growth management in salmon farming. Fish and animals have requirements for specific amino acids and they build proteins with combinations of about 22 amino acids. Their optimal nutrition is to be found in fishmeal and fish oil as a single package of micronutrients. These include calcium, phosphorus, magnesium, potassium, selenium, as well as vitamins such as B1, B2, B6 and B12. Some minor compounds (in terms of volume) have been identified in fishmeal that may be linked to superior performance in farmed animal feeds. These include taurine, trimethylamine oxide, nucleotides and glycosaminoglycans. Fishmeal also includes a component of fats (fish oil), usually at 8-12%, thereby also providing a supply of EPA and DHA (omega-3) outside of fish oil itself.

Studies from Nofima, the Norwegian research organisation, reported in 2019 that the barrier tissue of salmon is affected by zinc and omega-3 levels in feed. As highlighted by the sea lice issue mentioned below, the barrier tissue of salmon is critical for the fish to fight against pathogens. It is also an important physical barrier between the fish and its environment and helps the organism handle physical stressors such as fluctuations in temperature, salinity, or water quality in general.

With increased volumes of raw materials needed to develop aquafeeds and support the growth of aquaculture, a wide range of raw materials is being used and combined. Within this combination, fishmeal and fish oil are considered as THE strategic ingredients (FAO, SOFIA report, 2018, 2020). While the feed industry needs additional raw materials to fill in the fishmeal and fish oil gap, which remains stable at 6 million tonnes a year, “it doesn't have to move away for the use of marine ingredients”, as Alf-Goran Knutsen, CEO of salmon farmer Kvaroy, stated in an IntraFish article in September 2020.

Additional raw materials need to prove themselves as sustainable, ie environmentally, economically and socially speaking. Nutrition is a key component of the social and economic pillars of sustainability. Beyond the question marks that surround prices, volumes and environmental impacts resulting of inclusion of additional raw materials into feeds, it is vital to ensure that further potential changes in feed composition won’t affect the health and robustness of farmed species and therefore health and wellbeing of people. Quality feed means quality food.

Clearly, the salmon has a story to tell and some lessons to teach.

As an anadromous fish it raises awareness on the many different impacts that are to be expected from different environments. It also helps understand how the world is changing and how the water resources – rivers or oceans – are a reflection of these changes. What is observed on land ends up being observed in oceans.

Farmed salmon is a highly attractive species and is even gaining market shares following the covid-19 pandemic. It used to be considered as a luxury product a few decades ago. Now, thanks to decades of growth in salmon farming, it has become more and more accessible. To date, about 69% of the world’s salmon harvest is farmed, a share that has dominated the share of wild-caught salmonids since 1999, with Atlantic salmon being the most farmed species of salmonids.