Salmon is one of the most delicious and nutritious meals that you can feed your family, a protein source that is rich in healthy fats and anti-inflammatory Omega 3's. Whilst that generalized statement is true, it depends greatly on where the salmon comes from and what it has been fed.
Firstly, you need to know that the term “Atlantic” salmon has absolutely no bearing on where it is from, but rather it refers to the species. All salmon that you purchase in Australia that is labelled “Atlantic Salmon” is farmed, unless it is imported from Canada by a company called Canadian Way and you can expect to pay around $70 per kilo. If the Salmon comes from Australia, then it has been farmed in Tasmania, if it states that it is from Norway then it is also farmed and imported. As most of the Salmon sold here is from Tasmania, I will specifically be focusing on their farming practices in this article.
What are farmed fish fed?
Consider that wild salmon eat a variety of smaller fish, krill, plankton, fish eggs, aquatic bugs and algae; keep that in mind as you read on.
You might think that farmed fish would be fed a similar diet to their natural habitat and you have this image in your head of a worker throwing handfuls of tiny fish and bugs into the pools and the salmon rushing to the surface to feed. Unfortunately that isn’t the case, they are fed pellets, similar to what we feed our dogs and cats. You are going to read the ingredients and think I am being extreme but I can assure you this information is proudly listed by Tassal, the biggest Salmon producers in Australia, and is readily available on their website.
Land animal co-ingredients from the Australian poultry, cattle, pig and sheep industries such as poultry meal, feather meal, meat meal, blood meal, poultry oil.
When farmed salmon started in Australia the fish were originally fed from traditional marine food sources but the cost of this feed has increased exponentially with the depletion of wild fish and krill due to our love of fish oil supplements and the over fishing of our waters. The concern here is the replacement of marine proteins with completely foreign land based proteins. The commercial feed coupled with the higher water temperatures has detrimental impacts on the gut health of the salmon requiring the use of antibiotics.
Vegetable/grain ingredients such as wheat and its derivatives, soya protein concentrate, lupin meal, faba bean meal and canola oil.
Again the cost of fish oil has forced the use of vegetable and poultry oils to be the main oil source in the feed. Since the shift to this food source, the EPA and DHA (Omega 3 fatty acids) content has reduced by half.
Farmed Atlantic salmon from Tasmania, Australia from 2002 (fish oil diet)  and 2010 to 2013 (chicken fat/fish oil diet) : Content of EPA (white bars) and DHA (black bars) (mg/100 g, wet weight)
Small amounts of marine ingredients such as fishmeal and fish oil from wild-caught fish and marine trimmings.
The exact percentage is not listed, this coupled with the reduction in Omega 3’s found in the fish suggests the percentage is minimal.
Vitamins and minerals.
Synthetic forms of phosphorous, calcium, C, E, Zinc & Folic Acid. Required to supplement the low quality of the fish food.
Cartenoids such as astaxanthin and canthaxanthin.
Without the addition of carotenoids salmon would be pale grey in colour and would not at all resemble the rich orange colour of wild caught salmon. Wild caught salmon obtain their colour from eating a diet rich in krill which naturally contain this pigment. There are two synthetic forms of this carotenoid and one is more expensive than the other.
Astaxanthin has been found to be a safe additive in its synthetic form when added to fish feed. In fact, studies have shown that it’s powerful prevention strategy in health problems caused by oxidative stress.
Canthaxanthin on the other hand has been linked to vision loss, hepatitis, and allergic skin reactions. The most serious has been aplastic anemia, a life-threatening condition that requires immediate therapy, including blood transfusions. This additive is supposed to be banned in Australia and yet is has suddenly reappeared in our fish food. Tassal feed this to their salmon for the first two months of their life to obtain a darker colour, the darker the colour the high price obtained for the fish. We are so obsessed with the colour of our salmon that Crayola have named a colour after it and the fish industry price their fish by using a salmon fan.
We know the long term detrimental effects to our health by the overuse of antibiotics, whilst we can limit the amount that we ingest by prescription it is very hard to control our intake when it is in our food sources.
When you take away an animal's natural environment and completely change their original food source then you are going to end up with a completely different representation from the original. I would recommend that you think of farmed salmon in the same way that you view mass produced chicken, grain fed beef or for that matter any food source that has been unethically farmed. With reservation and concern; we need to vote with our money and speak our minds to achieve change.
I’ll leave you with this thought. Have you ever seen a fish eat a chicken?
• Neuman, Christina, Hatje, Eva, Stevenson, Hollie, Smullen, R, Bowman, J P, Katouli, M. Science and Education Publishing; 2014. The Impact of Diet on the Gut Microbiota of Tasmanian Atlantic Salmon (Salmo Salar L.) Using a Semi-Continuous Fermenter Model.
• Nichols, P. D., Glencross, B., Petrie, J. R., & Singh, S. P. (2014). Readily Available Sources of Long-Chain Omega-3 Oils: Is Farmed Australian Seafood a Better Source of the Good Oil than Wild-Caught Seafood? Nutrients, 6(3), 1063–1079. http://doi.org/10.3390/nu6031063
• Midtbø, L. K., Ibrahim, M. M., Myrmel, L. S., Aune, U. L., Alvheim, A. R., Liland, N. S., … Madsen, L. (2013). Intake of farmed Atlantic salmon fed soybean oil increases insulin resistance and hepatic lipid accumulation in mice. PloS One, 8(1), e53094. http://doi.org/10.1371/journal.pone.0053094
• Kitessa, S. M., Abeywardena, M., Wijesundera, C., & Nichols, P. D. (2014). DHA-containing oilseed: A timely solution for the sustainability issues surrounding fish oil sources of the health-benefitting long-chain omega-3 oils. Nutrients, 6(5), 2035–2058. http://doi.org/10.3390/nu6052035
• EFSA FEEDAP Panel (EFSA Panel on Additives and Products or Substances used in Animal Feed), 2014. Scientific Opinion on the safety and efficacy of synthetic astaxanthin as feed additive for salmon and trout, other fish, ornamental fish, crustaceans and ornamental birds. EFSA Journal 2014;12(6):3724, 35 pp. doi:10.2903/j.efsa.2014.3724
• Dhankhar, J., Kadian, S. S., & Sharma, A. (2012). Astaxanthin: a potential carotenoid. International Journal of Pharmaceutical Sciences and Research, 3(5), 1246+. Retrieved from http://go.galegroup.com.ezproxy.think.edu.au/ps/i.do?id=GALE%7CA360796750&v=2.1&u=think&it=r&p=AONE&sw=w&asid=63d2b6f385081bc43a2628519770caef
• Tanning pills no substitute for sun. (1991, October). Medical Update, 15(4), 6+. Retrieved from http://go.galegroup.com.ezproxy.think.edu.au/ps/i.do?id=GALE%7CA11493930&v=2.1&u=think&it=r&p=EAIM&sw=w&asid=09c7c5a85663b60d8b2f02455cbe0af3