AUTHOR: Agatha GEorgiou

Did everyone manage to catch the recent BBC Panorama – Salmon Farming Exposed? It gave us inspiration to deep dive into the environmental impacts of the fish farming industry. A staggering 90% of the world’s fish stocks are currently being overfished or are fully exploited. Today we eat fish as part of a standard meal, when 40 years ago it was considered a luxury.  Aquaculture has been developed to help meet this increasing demand for fish, but has this just enhanced our fish consumption, creating additional, unintended consequences?

Aquaculture now accounts for almost half of the seafood we consume globally. We are led to believe that this is helping divert pressures away from wild fish stocks, but this is not the case for carnivorous fish. To produce 1kg of farmed salmon we need to feed them 3kg of wild fish! Species such as anchovies, mackerel, whiting, herring and sardines are being caught to produce fishmeal and fish oil needed to increase weight and omega-3 levels. The more oily fish we feed salmon, the higher the omega-3 levels they will contain. But why not eat these species directly?  We are over-eating the same ‘big 5’: salmon, cod, tuna haddock and prawns instead of broadening our eating habits. By farming carnivorous fish we are also affecting whole communities in developing countries, depleting their local fish stocks by shipping huge volumes to Scotland for fish feed. Since the aquaculture expansion, 100% of Scotland’s salmon production is now farmed. The last wild Scottish salmon company closed its doors less than a year ago due to extremely low populations, the lowest levels ever recorded. Fish farms are being blamed for wild salmon deaths due to pollution, disease and sea lice.

Farmed salmon are held in open net cages, allowing them to benefit from naturally occurring oxygen rich currents. However, the seabed suffers from the large quantities of faeces and uneaten food that sinks to the bottom every day. This build up over time stops oxygen reaching the seafloor and bacterial mats are formed decreasing marine life in the surrounding areas.

Another serious problem is sea lice, which feed on the skin of fish. They attach themselves to farmed salmon in greater numbers than they would in the wild causing immense damage to their health and fitness. As naturally occurring sea lice eaters are unable to nip them off, fish farms are reliant on toxic outbreak treatments which are believed to negatively affect other crustaceans in the surrounding area. Infested salmon are also prone to escaping due to net damage from harsh weather conditions or hungry seals and cetaceans in the area and infect wild populations. Interbreeding of farmed and wild salmon also weakens wild populations as they have low fitness, produce less eggs, have no homing instinct for spawning, and lack the experience of dealing with predators.

By diversifying our eating habits and making environmentally responsible selections when buying seafood we can all play a key role in strengthening the future of our seas. Next time you fancy some salmon, why not switch to mussels? These can be sustainably farmed and don’t require additional fish to be caught to fatten them up. They are an equally healthy choice boasting high levels of omega-3 and vitamin B12! Rainbow trout which belongs to the same fishy family as salmon is another great switch; have a look at our One Planet Plate campaign website for more sustainable fish recipe ideas. But if you do buy salmon ensure it is organic, ASC certified or RSPCA assured which limit at least one of the environmental impacts – stocking densities. If you are unsure what fish species are sustainable, download the Marine Conservation Society’s Good Fish Guide app – green rated fish can be consumed with a guilt-free conscious, amber are a ‘think twice’, as there could be better alternatives and red is the fish you should be avoiding.

We’d like to say a big thank you to chef Merlin Labron-Johnson from SRA Member The Conduit who cooked us a feast fit for the king of fish at the launch of Feedback’s Fishy Business campaign to help reduce our reliance on wild stocks for fish feed. Below are some delicious meal ideas, using fish that would normally be fed to salmon, let’s all be inspired to try something new.