With the onslaught of Minamata disease in Japan in 1956, the ill effects of industrialization surfaced once again to haunt the world. The high levels of methylmercury released as industrial wastewater by the chemical factory of the Chisso Corporation, found its way into fish and shellfish of the Minamata Bay and the Shiranui Sea. These fish were eaten by the local population around the place, and what for so long was relished by locals as nourishing food soon became the source of mercury poisoning that led to the neurological syndrome called the Minamata disease.
Mercury is a naturally occurring element found in air, water, and land. Human beings are exposed to this element through food, especially through fish that ingest this in the form of methylmercury. While some have this toxic compound in higher levels, others have lower amounts of it. This led to the curiosity to know which fish are good to eat.
Fish and Mercury
Sea food has been an excellent source of nutrition for human beings. Fish and shellfish contain high amount of proteins and other important nutrients. They are low in saturated fats and are good source of omega 3 essential fatty acids that are very beneficial for our health. However, this same nutritious food can also be the carrier of the most toxic form of mercury, i.e., methylmercury. This organic form of mercury occurs in sea fish from mercury in ocean sediments. This mercury is converted into methylmercury by micro-organisms in the water (freshwater or marine), which then gets absorbed into the tissue of fish through their digestive tract―as they eat and gills―as they swim. Once this compound becomes a part of the tissue, cooking or any processing technique can't remove the compound from the meat.
The amount of mercury in fish depends upon their size, habitat, diet, location, and age of a fish. Hence, while some would have more of this toxic substance in them, there are those that have a lesser amount of the compound. Here is a list of fish that can be eaten:
- Black drum
- Bluegill Sunfish (Freshwater fish)
- Canned light tuna
- Farm-raised catfish (Freshwater fish)
- Farm-raised crayfish (Freshwater fish)
- Farm-raised trout (Freshwater fish)
- Ocean perch
- Red drum
- Salmon (canned, fresh or frozen)
- Southern kingfish (sea mullet)
- Speckled trout
- Tilapia (Freshwater fish)
- Trout (Freshwater fish)
- White grunt
Fish to Avoid
These fish have been found to contain very high amounts of mercury in them and hence, are suggested that they should not be consumed.
- Almaco jack
- Banded rudderfish
- Blackfish (bowfin, Freshwater fish)
- Cat fish - caught wild (Freshwater fish)
- Canned white tuna (albacore tuna)
- Crevalle jack
- Greater amberjack
- Jack fish (chain pickerel, Freshwater fish)
- Largemouth bass (statewide, Freshwater fish)
- South Atlantic grouper (gag, scamp, red and snowy)
- King Mackerel
- Little tunny
- Orange roughy
- Spanish mackerel
- Tuna (fresh or frozen, different species from the canned light tuna)
- Warmouth (Freshwater fish)
Fish to Eat During Pregnancy
Young children and especially, unborn babies are at the highest risk of getting poisoned by ingesting high levels of mercury. Studies have shown that babies in the womb of mothers who consume fish high in mercury content, are at a greater risk of developing neurological problems and suffering from slow development during the early years. Some fish that are safe to eat during pregnancy include shrimp, light canned tuna, anchovies, oysters, salmons, and sardines. Along with the fish, it is the amount that also needs to be taken into account. It is due to the impact of mercury that the Food and Drug Administration (FDA) and the Environmental Protection Agency (EPA) revised their advisories on mercury in fish in March 2004. Their advisories are:
- Pregnant women, nursing mothers, women who are planning to conceive and young children should avoid fish and shellfish that have high levels of mercury in them.
- Individuals of the above mentioned group can eat up to 12 ounces (2 average meals) a week of a variety of fish, and shellfish, lower in mercury, like shrimp, crab, cod, clams, scallops, canned light tuna, canned salmon, pollock, and catfish, among others.
- Albacore "White" tuna contains higher amount of mercury than other types of tuna. You can eat 6 oz or less of albacore tuna per week (about 1 serving).
The information about safe fish to eat provided in this article is based on general findings and should not be used as a substitute for medical advice. It is also advised to consult the local advisories for best knowledge of the amount of mercury in fish.