In an article by Dr. Russell Blaylock in Newsmax.com, Health Alerts he demyths the concept of "healthy" fish. The information is astounding to me and I think it is, at minimum, worthy of your consideration. Please read:
You read in the popular press about the many virtues of eating fish. Even the American Heart Association suggests that you eat fish rich in omega-3 fatty acids two times a week to keep your heart healthy.
So what's the problem?
A growing number of studies have shown that seafood often contains significant, and in some instances, very high levels of mercury. In addition, government regulatory agencies, as well as private studies, have shown that many fish, including shellfish, contain high levels of other pollutants, such as PCBs, dioxins, and pesticides/herbicides.
The EPA (which regulates fish from sports fishing) and the FDA (which regulates commercial seafood) have set limits for “safe” mercury levels in seafood, but they do not share their concerns about contaminants with the general public through the media or public alerts.
And herein lies the problem. There is no “safe” level of mercury in the body. Mercury is one of the most poisonous metals known. Doses less than a millionth of a gram are toxic to brain cells. Worse still, mercury, especially the type of mercury found in fish – methylmercury –tends to accumulate in fatty parts of the body and remains for decades. The brain is composed of 60 percent fats.
The EPA and FDA do list four fish that should never be eaten, including swordfish. Oceans Alive, an organization that focuses on protecting ecosystems and fisheries, lists the best and worst seafood to eat in terms of mercury and PCBs pollution.
How Protect Yourself Against Mercury
One obvious thing to do is to choose seafood that is naturally low in mercury contamination, such as clams, shrimp, wild Alaskan salmon, sardines, scallops, crab and other small, relatively young sea creatures.
Also, an individual’s resistance to mercury toxicity is quite variable. This is because many dietary factors can reduce its toxicity and enhance the body’s defensive mechanisms. For example, we know that much of mercury’s damage is secondary to its ability to generate numerous free radicals in the body. Hence, antioxidants, especially those working as a network, can reduce these free radicals. In part, this is how fish oils (the DHA components) help reduce the damage.