When purchasing fish, there are many choices to make. Do you prefer halibut or salmon? Or, if salmon, do you want coho salmon or sockeye salmon?.

Perhaps the most consequential choice you make when you purchase fish is whether you choose farm-raised or wild. Is there a difference? You bet there is.

A study of salmon from multiple parts of the world showed that in the vast majority of cases farm-raised salmon contain significantly higher levels of toxins than wild salmon. These toxins include a number of which are reasonably believed to be carcinogens, such as dioxins, toxaphene, and polychlorinated biphenyls, better known as PCBs.

Where do these toxins come from? They seem to be passed to farm-raised salmon through their food, a mixture of ground-up fish and fish oil. The levels of toxins found in the chow correlate with the levels found in the salmon that eat it.

Putting toxin concerns aside, wild fish swim freely all their lives. They're not cooped up in a crowded pen. As a result, wild fish are leaner than farm-raised fish. Wild salmon in particular are about 20% higher in protein and 20% lower in fat. At the same time, wild salmon are about 30% higher in Omega-3 fatty acid, a health-promoting fat which is one of the most touted benefits to consuming salmon.

What's the healthiest wild salmon to consume? Due to their efforts to conserve and protect wild salmon habitats, Alaskan salmon are your best bet. Not only are Alaskan salmon the healthiest, but in a blind taste test at the French Culinary Institute in New York City, wild Alaskan Coho salmon ranked number one.