American Eel

Like all anguillid eels, American Eels hunt predominantly at night, and during the day they hide in mud, sand or gravel very close to shore, at depths of roughly 5 to 6 feet.

American Eel
American Eels hunt predominantly at night, and during the day they hide in mud, sand or gravel very close to shore, at depths of roughly 5 to 6 feet. They feed on crustaceans, aquatic insects, small insects, and probably any aquatic organisms that they can find and eat.

Information & Facts:

Description

American Eels can grow to 1.22 m (4.0 ft) in length and to 7.5 kg (17 lb) in weight. Females are usually larger than males, lighter in color and 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. Gill openings are partly below pectoral fins, relatively well-developed and well separated from one another. Inner gill slits are wide.

The scales are small, rudimentary, cycloid, relatively well embedded below the epidermis and therefore often difficult to see without magnification. The scales are not arranged in overlapping rows as they often are in other fish species but are rather irregular, in some places distributed like “parquet flooring”. In general, one row of scales lies at right angle to the next, although the rows immediately above and below the lateral line lie at an angle of approximately 45°. Unlike other bony fishes, the first scales do not develop immediately after the larval stage but appear much later on.

Habitat

Eels are ‘bottom dwellers’. They hide in burrows, tubes, snags, masses of plants, other types of shelters. They are found in a variety of habitats including streams, rivers, and muddy or silt-bottomed lakes during their freshwater stage, as well as oceanic waters, coastal bays and estuaries.

Individuals during the continental stage occasionally migrate between fresh, salt and brackish water habitats and have varying degrees of residence time in each. During winter, eels burrow under the mud and enter a state of torpor (or complete inactivity) at temperatures below 5 °C.[25] although they may occasionally be active during this period.

Temperature requirements are suggested to be flexible. It has been found that American eels during elver stage can survive temperature as low as −0.8 °C.

American Eels move from freshwater to estuaries and coastal bays to feed during spring, then either return during the fall or head south to the spawning grounds. Eels are extremely mobile and may access habitats that appear unavailable to them, using small watercourses or moving through wet grasses.

Feeding

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.

Life Cycle

The American eel’s complex life history begins offshore in the Sargasso Sea in a semelparous and panmictic reproduction. Young eels then drift with ocean currents and migrate inland into streams, rivers and lakes.

This journey may take many years to complete with some eels travelling 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.

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American Eel
American Eel
Conservation Status
Conservation Status

Endangered (IUCN 3.1)

Scientific Classification
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Anguilliformes
Family: Anguillidae
Genus: Anguilla
Species:
A. rostrata
Binomial Name

Anguilla rostrata

American Eel Range Map

American Eel Range Map