You Ask, I Answer: Farmed Salmon/PCBs

I read on your blog that farmed salmon are fed grains and get their color by eating dye pellets. Yuck.

I have also heard that farmed salmon isn’t good for you because of PCBs. What is that all about?

-- (Name withheld)
San Francisco, CA

Although salmon is universally touted as a healthy food, its environmentally -- and nutritionally -- toxic profile differs depending on whether that fillet you are eating comes from a wild–caught or farmed specimen.

Whereas wild salmon freely roam ocean waters, farmed salmon share open-water netted pens (pictured at left) with thousands of other cohorts.

I suppose you could call them the “Manhattan”-ites of marine animals -- happily (or seemingly so) living in a shoebox.

Salmon farms are the equivalent of cattle feedlots -- they produce enormous volumes of waste (think nitrogen and fecal matter) that usually end up contaminating surrounding waters.

Where do polychlorinated biphenyls (PCBs) come in?

Well, you can thank the human species for that. PCBs were mainly used as lubricants, adhesives, and coverings for electrical wirings several decades ago.

They were banned in 1976 due to health and environmental concerns.

What concerns, you ask?

From a health standpoint, PCBs have specifically been linked to a variety of cancers, nervous system damage, and fetal abnormalities.

Mother Earth doesn't fare much better. Turns out PCBs accumulate in the environment very quickly, since they disintegrate at a snail's pace.

No, make that a snail moving through cement's pace.

Since, literally, hundreds of tons of PCBs were dumped into various waterways by companies and treatment plants in the 50s and 60s, the damage has certainly been done.

But if this affects many waterways, how come farmed salmon have higher PCB levels than their wild counterparts?

First, their diet is different.

As you said, farmed salmon are fed large quantities of grains. Ah, but that's not all -- they are also provided plenty of fish oil to snack on.

See, PCB’s accumulate in the fatty deposits and oils of fish. Farmed salmon have that freely available to them; wild salmon don't.

Since farmed salmon are overfed, they weigh more (have more fat) than their wild counterparts. In other words, more deposits for PCBs.

We're not just talking twice as many PCBs, either. Studies by a variety of environmental groups have concluded that the levels of PCBs in farmed salmon are anywhere from 12 to 18 times higher than wild salmon!

It is for this reason that farmed salmon intake is recommended to not surpass one meal a month.

It doesn’t help that wild salmon is more expensive and, as Marian Burros of the New York Times discovered a few years ago, a lot of “wild salmon” is actually farmed.

What is a health conscious shopper to do? Besides realize that humans have been treating the planet like absolute crap for the past few decades?

Well, I suggest buying canned sockeye salmon or, if your budget permits, frozen Alaskan salmon, both of which are always wild.

That's right -- canned salmon labeled “Atlantic salmon” is often farmed.

In any case, salmon is not the only fish in the sea.

Many other delicious species offer plentiful Omega-3 fatty acids, including black cod, halibut, catfish, pollock, and mackerel.