Eels are elongated fish, ranging in length from to , and are used in various cuisines around the world. Japan consumes more than 70 percent of the global eel catch.
Eel blood is poisonous to humans and other mammals, but both cooking and the digestive process destroy the toxic protein.
Freshwater eels (unagi) and marine eels (anago, conger eel) are commonly used in Japanese cuisine; foods such as unadon and unajuu are popular but expensive. Eels are also very popular in Chinese cuisine and are prepared in many different ways. Hong Kong eel prices have often reached 1000 HKD per kilogram and once exceeded 5000 HKD per kilogram. Eel is also popular in Korean cuisine and is seen as a source of stamina for men. The European eel and other freshwater eels are eaten in Europe, the United States, and other places. Traditional east London foods are jellied eels and pie and mash, although their demand has significantly declined since World War II. In Italian cuisine eels from the Valli di Comacchio, a swampy zone along the Adriatic coast, are especially prized along with freshwater eels of Bolsena Lake. Eels are popular in the cuisines of Northeast India. Freshwater eels, known as kusia in Assamese, are eaten with curry, often with herbs.
Eels are a Priority Species under the UK Post-2010 Biodiversity Framework. The European eel (Anguilla anguilla) is listed as Critically Endangered on the global IUCN Red List of Threatened Species. While the Japanese eel (Anguilla japonica) and American eel (Anguilla rostrata) are assessed as Endangered.
In 2010, Greenpeace International added the American eel, European eel, and Japanese eel to its seafood red list. "The Greenpeace International seafood red list is a list of fish that are commonly sold in supermarkets around the world, and which have a very high risk of being sourced from unsustainable fisheries."
The US government deems the commercial eel industry was worth $12 million in Maine in 2017.
The eel was a cheap, nutritious and readily available food source for the people of London; European eels were once so common in the Thames that nets were set as far upriver as London itself, and eels became a staple for London's poor. The first "Eel Pie & Mash Houses" opened in London in the 18th century, and the oldest surviving shop â M.Manze â has been open since 1902.