The European eel and the American eel are members of the true eel family that comprises 15 species worldwide. All of these eels are catadromous, meaning they inhabit fresh or brackish water for most of their lives but spawn in the ocean. Eels have an extraordinary life cycle. They hatch at sea, then migrate long distances back to coastal estuaries. Eventually, they travel upstream where they live for 5 to 20 years in various aquatic habitats (ponds, river basins, tidal creeks); at this time they are called yellow eels. They then metamorphose into silver eels, and when sexually mature, return to the ocean to spawn and die. Both American and European eels are thought to spawn exclusively in the Sargasso Sea, however each species returns to its respective side of the Atlantic Ocean. Consequently, American eels are native to North American watersheds on the eastern seaboard.
Full grown European and American eels can reach a length of 3 to 4 feet and can weigh 10 to 20 pounds. These eels are also considered a delicacy and as such are heavily harvested for human consumption.