There's no corn in the ocean

Philip J. Goscienski, M.D.

October 2012

Fish farming is nothing new. The Egyptians of 4,000 years ago as well as the ancient Chinese figured out that if sheep and cattle could be raised in pens, fish could too. Modern aquaculture accounts for nearly half the commercial fish production in the world and in the case of some species it is almost 100 percent.

Fish and shellfish provide quality protein and are the major source of omega-3 fats. Insufficient intake of the latter is perhaps the single most important nutritional deficiency of the modern age. However, the huge rise in the demand for fish has generated some of the same problems as animal husbandry: environmental pollution, health hazards and economic controversy.

Salmon farming illustrates some of the problems that this industry has to contend with. Almost all the Atlantic salmon that appears on any menu comes from aquatic farms. Salmon that live in the ocean, lakes or streams have never seen a kernel of corn or tasted a soybean but a significant portion of the diet of farmed fish is based on corn or soy products. Much of it also comes from fish meal but that is expensive by comparison and it contributes to the accumulation of toxic chemicals. Wild salmon are much more active and free-ranging than their caged counterparts. The latter, like beef cattle raised in feedlots, are fatter for the same reason, the lack of activity. Crowding increases the risk of infection by viruses, bacteria and parasites so that antibiotics are used often and die-offs occur when no treatment is available. Concentrated fecal matter harms local ecosystems

Perhaps the pharaohs' fish farmers had to deal with pollution but it probably didn't come in the form of mercury, dioxin and other modern pollutants. The fish harvested from some areas, such as that from the North Atlantic have relatively high levels of these toxins. Scientific bodies have recommended that it is prudent to eat no more than one or two servings of these fish per month. Wild salmon from the Pacific Northwest may be tainted but the levels of contamination are low enough so that the benefits of eating these fish outweigh the hazards. Pregnant women should limit their intake to the smaller varieties of fish such as trout, tilapia and sardines and avoid swordfish, shark, tilefish and king mackerel.

On balance, eating fish is far healthier than avoiding it, even during pregnancy.

Philip J. Goscienski, M.D. is the author of Health Secrets of the Stone Age, Better Life Publishers 2005. Contact him at