The eel begins and ends its life in the waters of the Sargasso Sea, an area north of the Bahamas. The leptocephalus, a pelagic larvae of less than two inches in length, drifts with the ocean currents for 9 to12 months before entering coastal waters. In autumn the glass eels migrate into estuaries along the Atlantic coast, including Chesapeake Bay, where they become pigmented. These eels are known as elvers. Some elvers remain in the estuaries, but others migrate varying distances upstream, often for several hundred kilometers, overcoming seemingly impassible obstacles such as spillways, dams, falls and rapids.
Females reach a maximum length of five feet, and males grow as long as two feet.
These residents of the Chesapeake Bay and its tributaries are nocturnally active omnivores, feeding on insects, mollusks, crustaceans, worms and other fish. Before beginning its life-ending migration back to the waters of the Sargasso Sea to spawn, the eel must undergo further profound physical changes. Just prior to the reproductive migration, the eel stops feeding, the eyes and pectoral fins enlarge, the visual pigments change and the body color pattern transforms. The migration occurs throughout autumn nights with adults descending streams and rivers, swimming through deep grass and shallow ditches, for a January spawning in the warm Caribbean waters. In the Chesapeake Bay area, most are collected in pots and support an extensive fishery.