Farmed fish - what you need to know

While incorporating fish and other seafood into the diet is an excellent way to consume essential omega-3 and omega-6 fatty acids, it pays to be picky about the fish you buy. Unfortunately in a world with a burgeoning population to feed, and where ocean fishing is both time consuming and expensive for many producers (not to mention questionable for our eco system), an overwhelming amount of seafood available for purchase comes from fish farms.

What is farmed fish?

By very definition, a fish farm is a place where fish are artificially bred or cultivated. The United Nations’ Food and Agriculture Organisation reports that the aquaculture industry is now growing three times faster than land-based animal agriculture, and is likely to continue growing. Given this artificial environment, there is a vast and distinct difference in fish bred on these farms versus wild caught fish.

According to PETA, more than 40 per cent of all the fish consumed each year are now raised on land-based or ocean-based aquafarms. It is in these farms that fish spend their lives in cramped, filthy enclosures, where many suffer from parasitic infections, diseases and injuries. To help ward off disease, heavy doses of pesticides, antibiotics and other chemicals are added to the aquafarms. Not only is this consumed directly by the fish (thereby passing on to us as consumers when we eat the fish) but these pesticides use to treat disease end up circulating throughout the ocean, damaging other marine life.

From an environmental perspective, fish farming also has disastrous effects. As farmed fish are carnivorous, they must be fed large quantities of ocean-caught fish to help them grow and re-produce, meaning that farmers source feed from the ocean simply to feed their fish farms. To keep costs low, some farms feed fish oil and fishmeal to fish who naturally only eat plants in an attempt to quicken the growing process.

So what does this mean nutritionally? Research has suggested that farmed fish contain less usable omega-3 fatty acids than wild-caught fish and a 20 per cent lower protein content. A USDA review subsequently confirmed this these findings. Further, some studies in the US, Canada, Ireland and the UK have shown that a cancer-causing chemical, known as polychlorinated biphenyls (PCBs) exist in farm-raised salmon at 16 times the rate of wild salmon. Authors of the study (view here for more information) concluded that concentrations of several cancer-causing substances are high enough to suggest that consumers should consider restricting their consumption of farmed salmon. In most cases, consumption of more than one meal of farmed salmon per month could pose unacceptable cancer risks according to US Environmental Protection Agency methods for calculating fish consumption advisories.  It is no secret either that fish farms are known to use canthaxanthin, which is a synthetic pigment that adds a pink colour to farm-raised salmon to make it look more ‘natural’.  

What can we do? 

When buying fish at your local store or ordering fish at a restaurant, make sure you ask about its origin. Most stores should have adequate labelling on each fish that will tell you, but if in doubt, be sure to ask. This goes for restaurants too. My guess is that most menus won’t want to advertise the fact that their chef uses farmed fish, so be sure to ask the question. As always, it pays to be an informed consumer. As with all health food, it may cost more to buy wild-caught seafood, however the health risks of consuming farmed products should more than justify this additional cost.