With the trend toward less consumption of animal products such as beef, poultry and dairy, many people have increased their intake of fish. Is fish a healthy alternative? Fish is an excellent source or protein, nutrients and Omega-3 fats. But some types of fish contain high levels of mercury, which could lead to health problems. Fish absorb the mercury from water pollution. Organic mercury can build up in the body of fish and builds up in our bodies when we eat fish that contain mercury. Over time, this can become a health issue. Studies have shown that much of the fish we eat has mercury levels higher than recommended for good health. The amount of mercury in fish and other seafood depends on the species and the pollution in their environment. Larger and older fish like shark, swordfish, fresh tuna, marlin, king mackerel, tilefish from the Gulf of Mexico, and northern pike, tend to contain more mercury.. These larger fish accumulate mercury when they consume smaller fish (which consume mercury from sea plants). Swordfish: 0.995 ppm (parts per million), Shark: 0.979 ppm, King mackerel: 0.730 ppm, Bigeye tuna: 0.689 ppm, Marlin: 0.485 ppm Canned tuna: 0.128 ppm Of note, salmon and shrimp were found to have much lower concentrations. The FDA advises pregnant or breastfeeding women, who are at high risk of mercury toxicity, to follow these recommendations: Eat 2–3 servings (227–340 grams) of a variety of fish every week. Choose lower-mercury fish and seafood, such a salmon, shrimp, cod and sardines. Avoid higher-mercury fish (see list above) When choosing fresh fish, check out info about the sources and advisories for their habitats. Following these recommendations can help you gain the benefits of consuming fish and minimize your risks of mercury exposure.