How many eggs can an American eel lay in a year?

The American eel is a facultative catadromous fish found on the eastern coast of North America. The American eel has a slender snakelike body that is covered with a mucous layer, which makes the eel appear to be naked and slimy despite the presence of minute scales. A long dorsal fin runs from the middle of the back and is continuous with a similar ventral fin. Pelvic fins are absent, and relatively small pectoral fin can be found near the midline, followed by the head and gill-covers. Variations exist in coloration, from olive green, brown shading to greenish-yellow and light gray or white on the belly. Eels from clear water are often lighter than those from dark, tannic acid streams.

The eel lives in fresh water and estuaries and only leaves these habitats to enter the Atlantic Ocean to start its spawning migration to the Sargasso Sea. Spawning takes place far offshore where the eggs hatch. The female can lay up to 4 million buoyant eggs a year, and dies after egg-laying. After the eggs hatch and the early-stage larvae develop into leptocephali, the young eels move toward North America where they metamorphose into glass eels and enter freshwater systems where they grow as yellow eels until they begin to mature.