Anguilla rostrata
FAMILY
Anguillidae
TAXONOMY
Muraena rostrata Lesueur, 1817, Cayuga Lake, New York.
OTHER COMMON NAMES
English: Common eel; French: Anguille américaine; German: Amerikanischer Aal; Spanish: Anguila Americana.
PHYSICAL CHARACTERISTICS
Males grow to 59.84 in (152 cm) and females to 47.24 in (120.0 cm); these eels weigh as much as 16.16 lb (7.330 kg). The major difference between the European eel and the American eel is the number of vertebrae, which is 110 to 119 and 103 to 111, respectively. Otherwise, the species are almost identical.
DISTRIBUTION
Western Atlantic from Greenland and the Atlantic coast of Canada and the United States to Panama and throughout much of the West Indies south to Trinidad. The range includes the Great Lakes, the Mississippi River, and the Gulf basin. It has been introduced to Guam and Japan.
HABITAT
At sea they are found over rather deep waters; in freshwater they are inhabit permanent streams with continuous flow.
BEHAVIOR
Individuals of this species are solitary and nocturnal. While in freshwater, they hide during the day in undercut banks and in deep pools near logs and boulders and sometimes bury themselves in the substrate, whether mud, sand, or gravel. At night they typically swim near the bottom in search of food. They can breathe through the skin along with their gills and are able to live for several hours outside water.
FEEDING ECOLOGY AND DIET
Like the European eel, food items vary with the stage of development and location. The leptocephalus larvae, for example, is planktivorous; the elver feeds on aquatic insects, small crustaceans, and dead fish; and the adult eats insects, crustaceans, clams, worms, fish, frogs, toads, and dead animal matter. Sharks are their main predator.
REPRODUCTIVE BIOLOGY
Despite many attempts to conduct direct observations, knowledge of reproductive behavior can only be inferred, based on circumstantial evidence. We know that during the autumn adults migrate to the Sargasso Sea to spawn, with spawning taking place in January. At that time, females lay up to four million buoyant eggs, dying shortly after. After fertilizing the eggs, the males also die. With the help of ocean currents, the leptocephalus larvae drift toward coastal waters for as long as 18 months. After becoming an elver, American eels undergo a slow transformation that includes increases in their size, eye diameter relative to body size, and in the amount of eye pigments. They also become darker along the body. They spend most of their lives (up to 20 years) in freshwater before returning to the sea for spawning.
CONSERVATION STATUS
Not listed by the IUCN. It has been listed as "rare" by a number of U.S. counties and states, but lacks specific legislation to protect it. Nonetheless, fishery authorities in the United States are taking measures to decrease the impact of fisheries, particularly at the larval and elver level. The Atlantic States Marine Fisheries Commission is preparing a Fishery Management Plan (FMP), requesting that the U.S. federal government include this species under some protection status under the supervision of the U.S. Fish and Wildlife Service.
SIGNIFICANCE TO HUMANS
They are consumed as food and prepared in many ways. Larvae and elvers (considered a delicacy) are captured using fine mesh fyke nets and dip nets; adults are caught with eel pots and trot lines. Although they can be caught in considerable numbers, their handling can be difficult, because the adults exude a noticeable layer of slime over the entire body. Moreover, large eels actively bite when caught on a hook and line.
