European eel

The European eel (Anguilla anguilla) is a special kind of eel. For a long time, people did not know much about their lives, and scientists have not seen them mating in the wild.

These eels are now in big trouble because of hydroelectric dams, overfishing by fisheries along the coasts, and harmful parasites. They are listed as critically endangered, meaning there are very few left and we need to protect them.

Description

European eels have five stages in their life: larva (leptocephalus), glass eel, elver, yellow eel, and silver eel. Adult yellow eels are usually about 45–65 centimetres (18–26 in) long, but they can grow up to 1.33 metres (4 ft 4 in) in rare cases. They have between 110 to 120 vertebrae and can live around 15–20 years in the wild. One eel named "the Brantevik Eel" lived for 155 years in a well in a home in Sweden.

Eels can be found from the surface down to 700 metres (0–2,297 ft) underwater. After laying eggs in the Sargasso Sea, they travel north through the Atlantic Ocean, along its coasts, and into rivers. They mainly hunt for food at night using their sense of smell, eating worms, fish, mollusks like slugs, crustaceans such as crayfish, and sometimes plankton. Larger eels, herons, cormorants, and pike eat eels. Seagulls also eat young eels called elvers. Eels like to hide in plants, rocky crevices, or muddy fields for shelter.

Conservation status

The European eel is a critically endangered species. Fewer eels reach Europe now than before. Many eels are caught for food, and some get stuck by dams. Changes in the ocean also affect them. People are working to protect eels.

Groups like Greenpeace International help make rules for catching eels safely. Scientists are trying to breed eels in labs. They have kept baby eels alive for months, but there is still more to learn about eels.

Life history

Main article: Eel life history

For many years, people did not fully understand the life of the European eel. Unlike other fish, eels start their lives in the ocean but spend most of their time in rivers, lakes, or coastal waters. They then return to the ocean to have their babies and die.

Scientists think the eels travel to a place called the Sargasso Sea to lay eggs. After hatching, tiny eel babies, called larvae, drift back toward Europe. When they reach the coast, they change into a see-through stage called "glass eel" and move into rivers. These young eels, now called elvers, grow into what we usually think of as an eel, with a yellow color on their sides. After many years, they change again, becoming silver-colored and getting ready to return to the ocean. This change helps them make a long trip back to where they started. Some eels stay in saltwater their whole lives, while others move between different kinds of water.

Commercial fisheries

Eel farming uses special pools to grow young eels from the wild until they are ready to be sold. Farmers also use coastal areas with barriers to raise eels. New eels are kept apart at first to stop diseases from spreading, and they are checked and sorted often.

Eels are fed special food after a few days of eating small fish eggs. They need clean water and the right temperature to grow well. Transportation to markets is done carefully by road or air to keep the eels safe.

Diseases can spread quickly in farms, so careful steps are taken to keep eels healthy. The trade of European eels has restrictions, and much of the eel industry depends on wild eels because farming them has not been very successful. Many countries around the world, including the United States, Japan, China, Scandinavia, Europe, Australia, Morocco, and Taiwan, are involved in raising or selling eels.