The eel is a migratory fish which spends most of its life in freshwater and migrates to the sea to breed. It travels many miles from its proper habitat to the Sargasso Sea, where it deposits its eggs. Initially the larvae remain at their birthplace, feeding on plankton. They then drift on the seas current until eventually arriving back at the coast. This can take up to three years depending on circumstances. These young fish are called elvers. On reaching the coasts, most of the elvers begin to swim upstream (similar to salmon). Due to the numerous man-made obstacles now found in rivers, special passes or fish ladders have been constructed to facilitate the eels‘ climb.
Only after three to four years of freshwater habitation do eels form their scaly skin and exhibit their characteristic yellow colour. They feed mainly on smaller animals and sometimes hunt larger prey when older. Eels are bony fish with very thick, leathery skin and a muscular, snake-like body. Females are decidedly larger than males and can weigh up to six kilograms and grow to a length of one metre. Males on the other hand grow to an average length of only 40 to 50 centimetres.
Eels grow very quickly and evolve with age into so-called silver eels. Their skin darkens and the belly takes on a shiny silver colouring. Only at this stage do the sex organs begin to emerge and they slowly prepare for their migration back to sea by eating large quantities of fat. In the period from August to October eels move primarily at night and their exact route to the spawning ground in the Sargasso Sea is still unclear today. Once there they spawn and then die. Eels which are prevented from reaching the spawning ground can live for up to 30 years.
