Eastern North America, Gulf of Mexico as well as northern South America.
Cold freshwater streams, estuaries and saltwater oceans
Although they seem more like snakes, eels are a kind of fish. The American eel is the only freshwater eel found in North America.
The typical full-grown eel is about 40 inches long and weighs 7 to 8 pounds, though specimens have been known to reach 50 inches and 10 pounds.
It has a long, snake-like body and a pointed head. The expression “slippery as an eel” comes from its mucus-coated skin. Like other fish, eels have gills for extracting oxygen from the water, but they can also breathe through the skin. In damp weather, they sometimes use that ability to travel over land in search of fresh water.
They are very successful scavengers that take advantage of habitats other fishes cannot utilize. Young eels feed mainly on insects and small crustaceans. As they got older and larger, the diet expands to include clams, crabs, fish, frogs, and worms. Eels also sometimes scavenge on dead animals.
The American eel is unique among North American fish in that they are catadromous. They live in freshwater but spawn in salt water. During late summer and early fall, eels begin migrating into the Atlantic Ocean and to spawning grounds in the Sargasso Sea, between the Azores and the West Indies. There, female lays as many as 4 million eggs, which are fertilized by the male. The adult eels die after spawning.
The fertilized eggs float to the surface, where they hatch and develop into larvae. Over the period of a year or more, ocean currents carry the larvae to the coast. Eels go through several stages of development. At this early time of life, they’re about 2 inches long and are known as glass eels because of their transparent bodies. Attracted to fresh water, the glass eels migrate into estuaries and fresh water.
As they grow, they become darker and are known as elvers. They’re still very small, reaching a length of only about 5 inches after a year in fresh water. Most elvers migrate upstream, as far as 600 miles, but some remain in estuaries. In either case, they enter a growth phase in which they’re known as yellow eels. The color actually ranges from yellowish to an olive-brown.
In their final life phase, the eels develop a bronze-black color on the back, with silver bellies, and they become sexually mature. They are now known as silver eels, and they’re ready to begin their migration.
Did You Know?
Eels face many obstacles. Adults are trapped for bait and food, glass eels (larvae) are caught by the thousands and sold overseas as a delicacy, and they face habitat loss due to damming and altering of natal rivers. But eels are tough and may circumnavigate dams by moving over land, or crawling vertically up dams.