March 25, 2016 — In an effort to make fish farming more sustainable, the aquaculture industry has been cutting back on feed made of other fish and replacing it with plant-based alternatives. But a new study warns that may make the fish less healthy to eat and have negative impacts on the environment.
Many fish species that are farmed, including Atlantic salmon, the most farmed fish in Canada, are carnivores that eat feed traditionally based on fish meal and fish oil. Environmental advocates such as Greenpeace have criticized the practice as unsustainable, as wild fish that could be used to feed people or maintain wild populations need to be caught in order to produce the fish food.
“They realized that we’re grinding up a lot of fish to feed the fish,” said Jillian Fry, director of the Public Health and Sustainable Aquaculture Project at Johns Hopkins University in Baltimore, Md.
The price of fish meal and fish oil has also increased with demand.
Omega-3 concerns
The study said the use of plant-based ingredients could reduce the amount of healthy omega-3 fatty acids in fish – one of the things that makes fish like salmon attractive and tasty to consumers.
While this is something salmon farmers are aware of and trying to avoid, Fry says, omnivorous fish that already eat more plant material and have less omega-3s, such as tilapia, may end up with even lower levels.
“Anywhere it’s decreasing in our diet, we need to pay attention.”