Antibiotics in aquaculture: getting the facts straight

Over Christmas, a strange science article was published by the New England Journal of Medicine.

The lead author, an economics professor from the University of Calgary, proposes a user fee for antibiotics in agriculture and aquaculture.

An economically rational solution is to impose a user fee on the nonhuman use of antibiotics. Every use of antibiotics increases selective pressure, thus undermining the value for other users. In effect, each antibiotic can have only a limited amount of use, so it is appropriate to charge a fee, just as logging companies pay “stumpage” fees and oil companies pay royalties.

It’s an interesting idea which got a lot of attention from the media in the post-Christmas doldrums, when media will traditionally desperately publish anything even remotely controversial to keep eyeballs on pages and screens (for the ads, of course!) until after New Year’s Day. However, the facts the author uses to back his premise are skewed.

A veterinarian working in salmon farming in BC took a look at the article and had numerous criticisms. Here’s what they pointed out.

No mention of pets

The article says that 80% of all antibiotics used in the USA are consumed by agriculture and aquaculture. But the graph in the article shows the bigger picture:

2014-02-27 09_40_41-Preserving Antibiotics, Rationally — NEJMIn the entire USA, aquaculture uses only 150,000 kg of antibiotics: the same amount as pets. But oddly, there is no mention of pets at all in the article. Why not? The author’s greatest concern is that “this profligate distribution of antibiotics around the world is contributing to the development and spread of resistant organisms” which may evolve and threaten human health. But he makes no mention of pets, which live with us, sleep with us, eat with us and share our space, every day.

The usage of antibiotics in pets should be of far greater concern than aquaculture. How many people come in contact with fish farms compared to pets? Yet this is not mentioned at all.

Aquaculture in context

The article specifically targets salmon farms (“Antibiotics are…added to food pellets and dropped to salmon in cages in the seas”), but farmed salmon production in the USA is a fraction of the whole, at about only 18,000 metric tonnes annually.

Catfish farmers in the USA produce nearly 272,000 metric tonnes of fish per year in freshwater ponds.

Aquaculture in the USA is dominated by catfish. On average, US catfish farmers produce 272,000 tonnes of fish per year. Farmed rainbow trout is the second largest aquaculture industry in the USA. Farmed salmon in the USA The total annual American aquaculture production is about 500,000 tonnes.

Aquaculture in the USA is using only about 300 grams of antibiotics per tonne of seafood produced.

Salmon farms in both the USA and Canada use even less than that average, ranging from 50 grams per tonne to as little as 5 grams per tonne of fish produced. 

That’s less than what people use. Going by this article’s numbers, the USA uses 11 grams of antibiotics per person, per year.

Other farmed animals use much more. The USA produces roughly 152,755,000 metric tonnes of livestock, poultry, dairy products and eggs each year. They all use antibiotics; however, this article only refers to livestock, which account for 33,000,000 tonnes per year.

Going by the article’s numbers, then, US livestock are using 410 grams of antibiotics per tonne produced.

Big assumptions miss the mark

The author shows a remarkable ignorance of agriculture and aquaculture in his list of reasons why he thinks a user fee for antibiotics would be a great idea.

He suggests that monitoring the actual usage of antibiotics would be challenging for farmers. Well guess what: BC salmon farmers already do this.

He also suggests that “veterinary oversight” would be a problem for “remote farms.” BC salmon farmers do this too. Regularly. Every treatment must be approved by a vet, who writes a prescription for medication.

According to the author, antibiotics are overused because they are cheap, $25 per kg by his reckoning. Not so. Antibiotics for aquaculture are more like $350 per kg. We like to use them as little as possible.

And finally, he suggests that a user fee on antibiotics would encourage farmers to look for antibiotic substitutes. Waaaay ahead of you there, pal. We’ve been using vaccines for years, along with good farming practices, good genetic stocks and top-quality feeds.

The goal is to keep our fish healthy throughout their lives. Unlike chickens, which only take about two months to grow to harvest, salmon take three years to reach harvest. While some chicken farmers may pump their animals full of medicine throughout their short lives as a precaution, this would never work on salmon farms. Using antibiotics constantly over three years would be expensive, would lead to resistance and would eventually become ineffective.

As much as possible, we use drug-free methods to keep our animals healthy. It’s economically viable, and the responsible way to farm salmon.

For more information about antibiotics used in aquaculture. the BC Salmon Facts website has some good facts and a video. 



7 thoughts on “Antibiotics in aquaculture: getting the facts straight”

  1. We don’t often eat our pets so what is the connection between antibiotics used to keep them healthy and those used in animals we comsume helping to create super bugs?

    1. How do you know antibiotics in pets aren’t also helping create superbugs? Do you deny that the risks to humans from pets are far higher than from seafood? Do you deny that humans risk far greater exposure every day from their pets and from neighbourhood pets than they do from fish farms on land or at sea?

      1. So you agree that giving antibiotics to animals is cause for concern. Therefore it logcially followes that giving animals antibiotics and then eating them to, mix with the human bacteria/viruses in out gut is of greater concern. Glad we got that straightened up!

  2. Nicely done. This is very good info about the careful use of medicines on salmon farms. For the original paper to generalize about medicinal use in farms is unfair and not helpful at all. Thanks for the facts – salmon farmers in North America are leaders in animal health.

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