All About The Effects Of Mercury In Fish
Nutritionists always tell us that fish is an important source of essential nutrients. However, there are some fish species that can transmit heavy metals such as mercury or foodborne diseases. Do you know the effects of mercury that are present in certain types of fish?
In connection with this, the World Health Organization (WHO) points out that the primary source of human exposure to toxic components is by eating seafood. These substances in particular affect our health and represent more than anything else a significant risk to pregnant women and breastfeeding mothers.
Why should one avoid some types of fish?
For several years it has been known that a large number of marine animals, especially those at the bottom of the food chain, can accumulate metals such as cadmium, lead and mercury, which come from, among other things, mining, livestock and agriculture. The effects of mercury in fish can be harmful to our body.
The concentration becomes so high that it can be life-threatening. The mass poisoning that took place in Minamata Bay in Japan in the early 1950s is actually the most recognized case of poisoning from having eaten fish with high levels of mercury.
The effects of mercury on human health
According to a study published in a medical journal in Chile , the toxicity and effects of mercury in fish are related to the chemical form, type, exposure dosage and age in which it originated. When this metal is released into the environment, it undergoes a number of changes and participates in cycles between the atmosphere, the sea and the earth.
The 5% that ends up in the water (including lakes, bays, wetlands, estuaries and gardens) is elemental mercury and accumulates in the substrate. The bacteria that live there convert it to methylmercury, which worms and other animals then extract.
It is an organic substance that fish end up ingesting, and it is the one that shows the greatest toxicity to living organisms, as it causes problems in the following:
- The nervous system.
- The immune system.
- The kidneys.
- Digestive system.
- The lungs.
- The skin.
- The eyes.
Types of fish that should not be eaten regularly due to the effects of mercury
Based on the above, there are species that can live more than 100 years, so the intake of these substances throughout their lives increases their potential for toxicity.
There are also large fish that end up eating large amounts because their intake is greater. Read on, because we will tell you what types of fish you should avoid.
King mackerel (Scomberomorus cavalla)
King mackerel is a sea animal with an elongated, spider-shaped body. It has a pointed snout and a wide mouth. It also has large eyes, which are surrounded by a dense, bony ring. Small scales cover its entire body and it has a clear blue-green back with pale, green flanks and a silvery belly.
It usually measures 65 centimeters, but males can reach a length of 2 meters. This species lives in the Atlantic Ocean from Canada and Massachusetts (USA) to Sao Paulo (Brazil).
Blue marlin (Makaira nigricans)
It is a species of marlin that can measure up to 4 meters, although it usually measures between 1.8 and 3 meters. It is known as blue marlin because of its color on the back. However, it also has a silver-white color on the abdominal area.
It has an elongated body and two dorsal fins. Its upper jaw is shaped like a sword. This fish usually lives in subtropical and tropical waters of the Atlantic Ocean, including the coast of the Canary Islands.
It is also found in the Pacific Ocean and the Indian Ocean. Females weigh up to 450 kg, while males usually do not exceed 160 kg.
Orange sawbug (Hoplostethus atlanticus)
This sea fish lives in the eastern and northwestern part of the Atlantic Ocean, the southern part of the Pacific Ocean and the Indian Ocean. Its body is oval and significantly compressed. It has a large head, small eyes and thin teeth. Fishermen usually recognize this species because of its dark orange body and red head.
The orange sawbug lives at depths of 180 to 1500 meters, and fishermen accidentally catch it by bottom trawling. The orange sawbug is the longest living fish known to live up to 180 years.
Atlantic cod (Gadu morhua)
The common cod, also known as Atlantic cod or Norwegian cod, is one of the 60 species of migratory fish. It lives in the Northeast Atlantic from the Barents Sea to the Bay of Biscay, including Iceland’s waters, Greenland and the Baltic Sea.
It is generally small, although some of them reach 2 meters in length and weigh up to 100 kg. They eat other fish such as herring and sardines. This species lives at a depth of 600 meters.
Big-eyed tuna (Thunnus obesus)
Big-eyed tuna is one of the species where there can be significant amounts of heavy metals. We should point out that this is not the case with tuna from the Mediterranean.
It lives in tropical and subtropical areas of the Atlantic, Pacific and Indian Oceans, but does not live in the Mediterranean. It reaches a maximum length of 2.5 meters, but usually reaches 1.8 meters at the age of about 15 years.
You should not consume these types of fish due to the effects of mercury
These are some species that can accumulate too many heavy metals, especially methylmercury. We should mention that there are other fish that contain heavy metals, but we have mentioned the species that typically have harmful levels of mercury.
Women of reproductive age, pregnant women, lactating women and children under the age of two are more vulnerable to these toxic substances due to the negative effects of mercury on health. Of course, this does not mean that other population groups are not affected.
Remember that it will not be harmful to eat moderate amounts of any of the mentioned fish. So you can do it occasionally, but just make sure it does not become a habit. You can enjoy the benefits of fish without risking your health!
