Eels are born through external reproduction that takes place in the ocean, specifically in the Sargasso Sea in the central Atlantic Ocean. Adult eels migrate thousands of kilometers to this spawning ground, where females release millions of eggs that are fertilized externally by male eels releasing sperm into the water. After hatching, the eel larvae, called leptocephalus, are transparent and leaf-shaped. These larvae drift with ocean currents for several years before metamorphosing into glass eels near coastal waters, then migrate into freshwater rivers and lakes where they mature into adult eels. Eventually, mature eels return to the Sargasso Sea to reproduce, completing the life cycle.
Eel Reproduction Process
- Adult eels migrate from freshwater or coastal areas to the Sargasso Sea to spawn.
- Eggs and sperm are released into the water in "clouds" for external fertilization.
- The reproductive adults die after spawning.
Early Development
- Eggs hatch into leptocephalus larvae, which are transparent and leaf-shaped.
- Larvae drift thousands of miles on ocean currents, feeding on tiny marine debris.
- On reaching continental shelves, they metamorphose into glass eels, then migrate into freshwater habitats to grow and mature.
Life Cycle Stages
- Leptocephalus larva
- Glass eel (near coastal waters)
- Elver (young eel)
- Yellow eel (juvenile to adult freshwater eel)
- Silver eel (sexually mature adult that migrates back for spawning)
This complex life cycle and long migration had baffled scientists for centuries and only recently confirmed by tracking studies.
