As a means of providing food for human consumption, fish farming has been around for centuries. However, the practice of rearing young Atlantic salmon in open water cages until they reach suitable market size is much more recent – not really coming to the commercial fore until the 1970s. This emergence owed much to the scarcity of wild salmon, which had seen it become a luxury product.

By increasing the availability of products at reasonable prices, salmon farming has boomed as an industry, with the fish now achieving incredible commercial success in markets all over the world, and successfully competing against other animal products. Salmon demand has in fact grown faster than any other seafood demand. In both the EU and the United States, it is in the top three of the most-consumed seafood categories, while the majority of consumers new to salmon are in markets in emerging economies, such as China and Brazil.

Reaching capacity

To facilitate salmon’s global growth and to capitalise on almost insatiable consumer demand, producers haven’t stood idle. Through new product innovation and more sophisticated farming systems, they have been able to dramatically ramp up production in recent decades. The latest industry analysis projects 2019’s global Atlantic salmon production will top 2.6 million tonnes, up 7% on last year, and that there will be 3.5% growth in 2020. Norway is the leading producer with 1.4 million tonnes, followed by Chile which expects to harvest around 740,000 tonnes this year.

There is a big challenge ahead, however. It is widely recognised that conventional cage farming in coastal zones offers only limited scope for salmon’s further growth, mainly due to the licensing constraints put in place by regulatory authorities and also because of very costly biological challenges such as sea lice.

To overcome this, some of the leading farming ventures have been developing new technologies and techniques that produce the species in closed containment systems, either on land or in remote offshore locations.

A myriad of concepts have been unveiled in recent years, and while there is considerable diversity in terms of the way they look and function, through the overriding priority of biosecurity, they have all been designed to reduce exposure to disease and environmental threats by preventing potentially harmful pathogens from entering the farm and to limit water exchange with the external environment.

Disruption of recirculating aquaculture systems

With additional benefits including stable production, location versatility, and lower dependency on medication, Recirculating Aquaculture Systems – or RAS – are at the forefront of this movement. Essentially, these are intensive, usually indoor tank-based systems that achieve high rates of water re-use through filtration and other treatments. While such technology has also been around for several years – mostly in hatcheries and applied with broodstock and juvenile fish –, there are high hopes for the latest generation of RAS systems for growing out market-ready salmon.

Dozens of new projects to farm salmon in land-based systems have been announced, and with more being added to the pipeline on an increasingly regular basis, the expectation is that RAS could be providing the market with between 250,000 and 500,000 tonnes of salmon within the next 10 years. That is from a current output of just 3,000 tonnes.

Perhaps not surprisingly, the majority of these new RAS ventures are being built in Norway. Although, it should be noted that the largest facilities that are currently under construction are actually in the US and China, which is attributed to the high-demand growth rates in these major seafood markets. After all, one of the main benefits of such systems is being able to produce a local product for a local market.

Novel aquaculture feeds

But salmon farming innovation doesn’t begin and end with the production system. It has also been identified that another potential limiting factor to the sector’s growth is feed, specifically access to the ingredients traditionally used in salmon diets that are sourced from capture fisheries. Therefore, while the inclusion rates of things like fishmeal and fish oil in aquafeeds continue to decrease, there is also a lot of R&D focused on delivering solutions – new raw material or novel ingredients that reduce the reliance further.

To date, the aquafeed sector has identified three emerging platforms with the highest probability of success.

Firstly, microbial meals, which is the culture of bacteria on feedstocks, such as methane gas, to create a high protein meal. Secondly, the culture of microalgae to produce oils rich in EHP and DHA amino acids. And thirdly, the culture of insects, such as the black solder fly, which in the larva stage can be fed various feedstocks to create feed proteins and lipids. Indeed, salmon farmed with algae oils and microbial or insect meals in the feed are already being marketed.

Looking ahead then, it is likely that several new aquaculture systems will enter the salmon farming space alongside a number of new, tailored diets for these fish. And that could be the platform from which the sector will continue to grow.