The Sargasso Sea is recognised by the accumulation of relatively warm, salty water found at greater depths than in any other area of the Atlantic ocean. The eel larvae are called leptocefaler after the spawning. Those small, thin, transparent organisms begin to float with the current northward towards the coasts of Europe. They reach their goal after around three years. By then, the larvae have developed into an elver, a kind of juvenile eel. The elvers show themselves in spring and summer as ålefaring (Danish expression - eel wandering), there they wander from the sea up the rivers and brooks - yes even over land. As long as it is damp, the eel can survive several days and nights on land. Some elvers remain in the sea, while others wander far up the water courses, usually until they meet waterfalls, rapids or dams. It is impressive how many miles the eel can convey himself into the brooks and lakes from the coast.

In the water courses, the elvers develop into yellow eels for many years. The males can grow up to 50 centimetres and the females up to a meter. They then change colour to a silver eel with a light abdomen and a black back before they begin to wander back to the sea. The males are normally nine years old while the females are 13 years old. Eel wandering from the lakes and rivers back to the sea takes place usually in September, October and November. This is the main time to fish eel with eel vessels and fish pots. It is crucial to know exactly when the eel decides to make the journey back to the coast. Tradition says that this occurs at the same time as one has a major break in the weather, rain, lighting and thunder. The eel generally moves with the autumn floods. The silver eel disappears eventually from the coast to swim the many thousand kilometres to the Sargasso Sea. Researchers believe this takes between three and four months but cannot say for sure how many eels reach this distant ocean area.

Many sports fishermen hunt for the really large types of eel that can be up to four kilos in weight. Eels reaching this size can be due to the fact that for different reasons they do not find their way back from the lakes and dams they have grown up in, or those who have lost their sexual instinct to swim back to the spawning areas. Some eels seem to develop an unnatural appetite, which means they put on a lot of weight.

The European eel (Anguilla anguilla) exists in the sea and fresh water from North Africa and the Mediterranean countries in the south, to the White Sea in the north. There are other species of eel in other areas of the ocean. For example, the American eel exists between the Gulf of Mexico to Labrador. Other species of eel are found in the Pacific Ocean and the Indian Ocean. The biologists claim that there is only one species of eel in Norway but many anglers distinguish between the pointed nosed eel and the square nosed type. Those two different types take different bait. The pointed nosed eel prefers earthworms while the square nosed is also tempted by dead bait fish.