Making farmed fish good for you

Way back when, in 2003, the journal Science reported that fish raised in captivity - farmed fish - were dramatically higher in toxic pollutants like dioxin, PCBs and pesticides than wild fish. Contaminated enough that the EPA said eating more than one serving a month of farmed fish posed a serious health risk.

Obviously, that's bad news for everyone involved. Fish farmers and the fish industry get hosed because they regularly tout their product as healthier than other animal-based foods. Health-conscious eaters, who think they're doing a body good by eating fish, are actually stockpiling PCBs and dioxins at a much higher rate than they would be if they stuck to hot dogs and chorizo. And obviously, the fish suffer because they're crammed into floating pens to maximize profits.

An interesting wrinkle in the aquaculture phenomenon developed this week as Canadian scientists announced that vegetarian salmon can be much healthier than traditionally carnivorous salmon.

It's a complex problem: Carnivorous fish are hit doubly hard by our human pollution. Since they exist downstream from our waste flows, they are literally swimming in our pollution. And by feeding on other fish that live in similar situations, salmon further increase their pollution intake.

For farmed fish, living in such tight quarters, being fed processed fish meal and fish oil, means the health problems are all the more increased. As the David Suzuki Foundation shows, antibiotics and pesticides are regular additions to farmed fishtanks and fish feed to keep the fish alive and free from sea lice infestations.

The Suzuki foundation has a solid examination of the many problems caused by aquaculture, including:

• Sewage from farms pollutes surrounding waters.
• Drugs, including antibiotics, are required to keep farmed fish healthy.
• Escapes of farmed fish (alien species) threaten native wild fish.
• Net loss: Farmed fish are fed pellets made from other fish - depleting other fish species on a global scale.

So the obvious solution to this is perhaps to stop farming fish, right? Try to rein in water pollution (which in the case of the Gulf of Mexico is due in large part to just a few farm counties) and let the fish thrive naturally? Nope. The obvious solution, from the aquaculture industry's perspective, would be to change salmon biology so the fish could tolerate plant-based foods instead of meat. Not only would fundamentally altering fish biology theoretically decrease the amount of toxins in fish-meat, but plant food is substantially cheaper than fishmeal.

It's hard to beat the profit motive, I suppose. Of course, perhaps some influential aquaculturalists read instead this news report from the University of Chicago that found vegan diets are best for people and the planet, and just took the idea to its extreme.