American Eel
Anguilla rostrata

The American eel is a smooth, snake-like fish that lives in rivers, streams and other freshwater areas throughout the Chesapeake Bay watershed.

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American eels are elongated fish that can vary in color from green or yellowish-brown to a darker shade of almost black. Above, an American eel is caught during the blue crab winter dredge survey in the Nanticoke River on March 9, 2020. (Photo by Will Parson/Chesapeake Bay Program) USAGE REQUEST INFORMATION The Chesapeake Bay Program's photographic archive is available for media and non-commercial use at no charge. To request permission, send an email briefly describing the proposed use to requests@chesapeakebay.net. Please do not attach jpegs. Instead, reference the corresponding Flickr URL of the image. A photo credit mentioning the Chesapeake Bay Program is mandatory. The photograph may not be manipulated in any way or used in any way that suggests approval or endorsement of the Chesapeake Bay Program. Requestors should also respect the publicity rights of individuals photographed, and seek their consent if necessary.

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Appearance

The American eel has a greenish, yellowish-brown or blackish body with a whitish belly. Its continuous fin streatches around its rounded tail from its back to its belly. Males grow to two feet in length and females grow three to five feet in length.

Feeding

The American eel is active at night and feeds at night on worms, small fish, clams and other mollusks, and crustaceans such as soft-shelled crabs. During the day, eels usually hide under a rock or bury themselves in bottom sediments.

Predators

Larger fish and fish-eating birds such as gulls, eagles and ospreys prey on the American eel.

Reproduction and life cycle

Eels are catadromous, meaning they live in freshwater rivers and spawn in the ocean. In October, sexually mature eels swim out of the Bay to the Sargasso Sea, an area of the Atlantic Ocean east of the Bahamas. In January, the eels spawn there, then die.

Tiny eel larvae drift in the ocean for 9 to 12 months. During this time, larvae transform to the “glass eel” stage. Ocean currents carry the transparent glass eels thousands of miles to the U.S. coast. Before entering the Bay, the glass eels become pigmented. These brown eels, called elvers, are only about 2.4 inches long. Some elvers stay in the Bay, but most continue to swim many miles up the Bay’s rivers to fresh water.

After a few months, the elvers transform into the adult “yellow eel” stage. Adults remain in freshwater rivers and streams for the majority of their lives. Once they reach sexual maturity, they return to the Sargasso Sea to spawn and die. American eels usually live for at least five years, though some eels can reach 15 to 20 years old.

Did you know?

  • The American eel is the only catadromous fish in the Bay region, migrating downstream to the ocean to spawn.
  • During their migration back up the Bay’s rivers and streams, American eels overcome multiple obstacles to reach their destination. They can slide over rocks, dams, wet grass and other seemingly impassable blockages.
  • Some people think that eels are snakes, but they are actually fish.
  • Eel is considered a delicacy in Asia and Europe. Most of the eels caught in the Bay region are exported overseas.

Sources and additional information

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