The promotion of the supposed health benefits of fish, combined with dwindling wild supplies, have spawned a dramatic expansion in aquaculture (farmed fish), increasing at an annual rate of 9.2 per cent.

Nearly half the fish consumed worldwide as food (43 per cent) are now raised on fish farms. In 1980 it was just nine per cent. Wildcaught fish have reached a peak at around 90-93 million tonnes annually, despite increasing demand due to a growing world population and there are no prospects of an increase in catches, according to the UN FAO. If fact, it’s all downhill from here on!

If people maintain their eating habits, an additional 40 million tonnes of food from the sea would be required by 2030 just to support current levels of consumption. This is clearly unsustainable and we have to look for alternatives – but fish farming is not the answer. Its demands on wild-caught fish as food and the spread of disease, sea lice and pollution are unacceptable and environmentally irresponsible.

Just as in other forms of factory farming, chemicals and antibiotics are widely used in fish farming and are just as harmful to human health. A chemical used to kill sea lice has been linked to testicular cancer, for example, and antibiotic resistant superbugs owe their appearance largely to factory farming.

In the wild, fish have become infected with deadly sea lice and other diseases caught from fish that have escaped from fish farms. There is even evidence of genetic pollution in wild salmon – factory-farmed fish breeding with wild fish and reducing their ability to survive. Couple this to the terrifying, automated scoop-it-all-up nets that catch everything in their path – and then throw back up to a quarter of the catch dead – and the pressure on the oceans is extreme and is unsustainable. The better and more sensible – in fact the only answer – is to obtain our omega-3 fats from sustainable plant sources.

(For more information on the environmental impact of fishing see Viva!’s guide End of the Line).