'Pharming' Our Salmon




In May 2020, the NGO Environment Tasmania published a story titled, Tassal salmon reports 260-fold increase in antibiotic use [1]. Not a misprint. This is not a misunderstanding of 260 percent vs 260-fold. This really was 260 times! This dramatic increase came from data reported in the Global Salmon Initiative (GSI), indicating that in 2018, Tassal had used 0.24 grams of active pharmaceutical ingredients per tonne of salmon produced, but in 2019 this had skyrocketed to 62.28 grams [2]. For reference, the amount used fluctuates from year to year, but the average is around 20 grams. Perhaps had Australia not been careening into Covid-19 lockdown, this story would have received more attention. 


This wasn't a one-off. "In 2008-09, Tassal pumped an astonishing 4.1 tonnes into its salmon, before heeding calls from authorities to cut down its use" [3]. By 2017, Tassal had come under fire for quadrupling its use of antibiotics while the other companies had reduced or eliminated theirs [3]. Tassal has a history of primarily using oxytetracycline, an antibiotic highly important in both human and veterinary medicine; whether this is still their go-to drug, we do not know. The lack of transparency is asphyxiating. We have a right to know. 


Here's why it matters. The World Health Organization (WHO) has flagged antibiotic over-use as one of the biggest threats to global health. Whether it's in humans or chickens or cattle or salmon, the microbes don't care. They're mutating toward drug-resistance, and our world is going to be a really different place where knee replacements, chemotherapy, and gonorrhoea lead to lethal infections without effective antibiotics. Screwing humanity in the pursuit of profit should be against the law. 


The salmon farming industry is one of the worst offenders when it comes to breeding antibiotic resistance. The Seafood Watch list produced by the Monterey Bay Aquarium is considered by many to be the holy grail of seafood guides [4]. In April 2014, they added farmed salmon to the red “do not eat” category. This surprised many people who both liked salmon and believed that it was farmed sustainably. The Red List action specifically applied to the world’s four largest salmon farming regions: Norway, Chile, Scotland, and British Columbia; other areas were still being assessed. The strongest concerns were overuse of sea lice pesticides, impact of escaped fish on wild populations, disease and parasite transfer between farmed and wild salmon, impacts of farm waste (effluent) with continued expansion into pristine areas, and especially, overuse of antibiotics that are critically important to human health. For example, in 2014, Chile produced 895,000 tonnes of fish and used 563,200 kilograms (1.2 million pounds) of antibiotics; in contrast, Norway has developed vaccines against some of the more common pathogens, enabling it to produce 1.3 million tonnes of fish in 2013, using only 972 kilos (2,138 pounds) of antibiotics [5].


Oxytetracycline, the antibiotic of choice for Tassal [3], has been strongly linked with antimicrobial resistance in fish farming, including salmon farming, in numerous studies [6].  


Besides contributing to antimicrobial resistance, there's another problem with using antibiotics: unhealthy residues in our food and in the rivers and ocean. The companies claim that after antibiotic treatment for illnesses, the fish are not harvested until time has passed for them to be free of the antibiotics. But that doesn't ring true to us. There's some questions that need to be asked, such as... 

  • What is the fate of the antibiotics administered in the hatcheries, where the waste water flows into the rivers? Where is the data on environmental impact of those antimicrobials?
  • What becomes of the antibiotics in the chickens and salmon that go into the feed? Do these residues remain in the salmon feed?



[Click here to go to Antibiotics References]

Image Pills by wuestenigel is licensed under CC BY 2.0