Farmed and dangerous
Unless you specifically buy wild fish, the chances are the fish you eat are raised on a fish farm and there are important nutritional differences between farmed and wild fish.
Farmed fish are likely to contain more fat than their wild cousins, but less omega-3s. Wild salmon can eat 10 times their body weight of smaller fish. To feed that amount of fish to farmed salmon is uneconomical, so much cheaper, manufactured pellets of soya, rapeseed or corn are used, combined with animal by-products, vitamins and minerals as well as wildcaught fish. Commercial fish feed may consist of just 35 per cent fish or less.
Organic fish feeds are made from the discarded filleting waste (blood, guts, tails and heads) of fish and shellfish caught for human consumption. As fish stocks are so low, the Soil Association are considering permitting up to 25 per cent oil seed in fish meal.
The outcome of using plant foods in fish meal is that the level of omega-6 fats in farmed fish has increased. Tilapia, the fish most in demand worldwide, has some of the highest levels of omega-6 in our food supply. This is not healthy!
Farmed fish can also contain pesticide residues and dangerous levels of POPs such as PCBs. A study of toxins in salmon feed, farmed salmon and wild salmon found that farmed salmon had consistently higher levels of contaminants, including PCBs. Other studies have confirmed this, meaning considerable health risks for those who regularly eat farmed salmon.
This is a crazy situation and there is no longer any convincing argument in favour of eating fish.