Eels and Lampreys may look similar, but fundamental physiological characteristics separate the two families. The first step to identifying an eel is to determine that it is not a lamprey.
Lampreys are parasites with round sucker mouths and no scales or paired fins. They have no bones; only cartilage.
Eel Life Cycle
Eels are catadromous, in that they spawn in the oceans, live out some of their lives there, and then migrate to freshwater for a longer period of their lives until they are ready to spawn again. The eel’s life cycle can be divided into seven stages. Eggs hatch into Leptocephalus eels, which are transparent, leaf-shaped larvae that drift on the upper surfaces of the open ocean for several years feeding on plankton. Leptocephali develop into Glass eels and begin to take on the typical eel shape. They are still transparent (thus the name), but their internal organs are visible, and their bodies can reach lengths of 4 inches. Glass eels migrate to coastal areas and congregate in the brackish waters of estuaries in great numbers. Some Glass eels begin to migrate upstream; others remain in the estuaries. Eels are so versatile and adapted to this freshwater migration that they find their way into most bodies of fresh water in the world; even scaling waterfalls and traversing land to do so.
Through their journey up freshwater channels, eels develop pigmentation and begin feeding on larger prey (crustaceans, worms and insects) in what is considered the Elver, or young eel stage. They begin to take on a yellow color as they reach 22 to 31 inches in length and are then known as Yellow eels. At this point they are considered to be sexually immature adults. Yellow eels will continue “running” upstream, crossing lakes and wetlands for up to 30 years, with some (females mostly) growing as large as 5 feet long. Those that remain in the estuary environment, continue through their life-cycle a lot more quickly than those that travel up freshwater. Those that do venture into freshwater tend to live longer and grow much larger.
When eels mature, they lose their yellow pigment and take on a dark grayish-brown color on top and silver underneath. Their eyes enlarge, their bodies thicken, and they discontinue feeding. Now referred to as Silver eels, they head back out to sea to spawn.
In Upstate NY we only have one species of Eel in our waters; the American Eel (Anguilla rostrata).
New York State Eel Identification Guide
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