American Eel

American eels can grow to 1.22 m (4.0 ft) in length and to 7.5 kg (17 lb) in weight. Females are generally larger than males, lighter in color, with smaller eyes and higher fins. The body is elongate and snake-like. Its dorsal and anal fins are confluent with the rudimentary caudal fin. It lacks ventral fins but pectoral fins are present. The lateral line is well-developed and complete. The head is long and conical, with rather small, well-developed eyes. The mouth is terminal with jaws that are not particularly elongated. The teeth are small, pectinate or setiform in several series on the jaws and the vomer. Minute teeth also present on the pharyngeal bones, forming a patch on the upper pharyngeals. Tongue present with thick lips that are attached by a frenum in front. Nostrils are superior and well separated.

The distribution of the American eel encompasses all accessible freshwater (streams and lakes), estuaries and coastal marine waters across a latitudinal range of 5 to 62 N. Their natural range includes the western North Atlantic Ocean coastline from Venezuela to Greenland and including Iceland. Inland, this species extends into the Great Lakes and the Mississippi River and its tributaries as far upstream as Minnesota and Wisconsin.

Eels are nocturnal and most of their feeding therefore occurs at night. Having a keen sense of smell, eels most likely depend on scent to find food. The American eel is a generalist species which colonizes a wide range of habitats. Their diet is therefore extremely diverse and includes most of the aquatic animals sharing the same environment. The American eel feeds on a variety of things such as worms, small fish, clams and other mollusks, crustaceans such as soft-shelled crabs and a lot of macroinvertebrate insects. A study on gastric examination of eels revealed that "macroinvertebrates, predominantly of the Class Insecta, were eaten by 169 eels (99% of feeding eels)" and "the stonefly Acroneuria was the single most numerically dominant taxon observed in the diet, occurring in 67% of eel stomachs that contained food".

The American eel's life cycle begins far offshore in the Sargasso Sea in a semelparous and panmictic reproduction. In 1926 Marie Poland Fish described the collection of eggs that she observed hatch into eels, which she expanded in her taxonomic description of the larval egg development. From there, young eels drift with ocean currents and then migrate inland into streams, rivers and lakes. This journey may take many years to complete with some eels traveling as far as 6,000 kilometers. After reaching these freshwater bodies, they feed and mature for approximately 10 to 25 years before migrating back to the Sargasso Sea in order to complete their life cycle.The eggs hatch within a week of deposition in the Sargasso Sea. Fecundity for many eels is between about 0.5 to 4.0 million eggs, with larger individuals releasing as many as 8.5 million eggs.

The major outlet for US landings of yellow and silver eels is the EU market.

During the 1980s and early 1990s, the American eel was one of the top three species in commercial value to Ontario's fishing industry. At its peak, the eel harvest was valued at $600,000 and, in some years, eel accounted for almost half of the value of the entire commercial fish harvest from Lake Ontario. The commercial catch of American eel has declined from approximately 223,000 kilograms (kg) in the early 1980s to 11,000 kg in 2002.