Mercury in fish in the context of "Methylmercury"

Mercury poisoning is a type of metal poisoning due to exposure to mercury. Symptoms depend upon the type, dose, method, and duration of exposure. They may include muscle weakness, poor coordination, numbness in the hands and feet, skin rashes, anxiety, memory problems, trouble speaking, trouble hearing, or trouble seeing. High-level exposure to methylmercury is known as Minamata disease. Methylmercury exposure in children may result in acrodynia (pink disease) in which the skin becomes pink and peels. Long-term complications may include kidney problems and decreased intelligence. The effects of long-term low-dose exposure to methylmercury are unclear.

Forms of mercury exposure include metal, vapor, salt, and organic compound. Most exposure is from eating fish, amalgam-based dental fillings, or exposure at a workplace. In fish, those higher up in the food chain generally have higher levels of mercury, a process known as biomagnification. Less commonly, poisoning may occur as a method of attempted suicide. Human activities that release mercury into the environment include the burning of coal and mining of gold. Tests of the blood, urine, and hair for mercury are available but do not relate well to the amount in the body.

Whale meat, broadly speaking, may include all cetaceans (whales, dolphins, porpoises) and all parts of the animal: muscle (meat), organs (offal), skin (muktuk), and fat (blubber). There is relatively little demand for whale meat, compared to farmed livestock. Commercial whaling, which has faced opposition for decades, continues today in very few countries (mainly Iceland, Japan and Norway), despite whale meat being eaten across Western Europe and colonial America previously. However, in areas where dolphin drive hunting and aboriginal whaling exist, marine mammals are eaten locally as part of a subsistence economy: the Faroe Islands, the circumpolar Arctic peoples (Inuit in Canada and Greenland, related native Alaskans, the Chukchi people of Siberia), other indigenous peoples of the United States (including the Makah of the Pacific Northwest), Saint Vincent and the Grenadines (mainly on the island of Bequia), some of villages in Indonesia and in certain South Pacific islands.

Like horse meat, for some cultures whale meat is taboo, or a food of last resort, e.g. in times of war, whereas in others it is a delicacy and a culinary centrepiece. Indigenous groups contend that whale meat represents their cultural survival. Its consumption has been denounced by detractors on wildlife conservation, toxicity (especially mercury), and animal rights grounds.

Fish oil is oil derived from the tissues of oily fish. Fish oils contain the omega−3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), precursors of certain eicosanoids that are known to reduce inflammation in the body and improve hypertriglyceridemia. There has been a great deal of controversy in the 21st century about the role of fish oil in cardiovascular disease, with recent meta-analyses reaching different conclusions about its potential impact.

The fish used as sources do not actually produce omega−3 fatty acids. Instead, the fish accumulate the acids by consuming either microalgae or prey fish that have accumulated omega−3 fatty acids. Fatty predatory fish, like sharks, swordfish, tilefish, and albacore tuna, may be high in omega−3 fatty acids, but due to their position at the top of the food chain, these species may also accumulate toxic substances through biomagnification. For this reason, the United States Environmental Protection Agency recommends limiting consumption (especially for women of childbearing age) of certain (predatory) fish species (e.g., albacore tuna, shark, king mackerel, tilefish and swordfish) due to high levels of the toxic contaminant mercury. Dioxins, like PCBs and chlordane, as well as other chlorinated cyclodiene insecticides are also present. Fish oil is used in aquaculture feed, in particular for feeding farmed salmon.