Also found in: Dictionary, Thesaurus, Medical, Wikipedia.


(vertebrate zoology)
A large order of actinopterygian fishes containing the true eels.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



(also Apodes), an order of fish (the eels) of the superfamily Teleostei. The body, which measures up to 3 m in length and may weigh up to 65 kg, is snakelike and usually scaleless. The dorsal and anal fins are long and often fused with the reduced tail fin, while the ventral and sometimes pectoral fins are absent. The eel develops through metamorphosis, beginning life as a translucent, leaf-shaped larva, or leptocephalus, that is entirely different from the adult eel. There are 22 families, embracing 350 species.

Eels are mainly marine fish, living in warm seas. Only one family lives in fresh water, and the remaining families are sometimes called marine eels. Most marine eels live in shallow water, where they stay hidden in rock clefts and coral reefs or in burrows made in the bottom. Members of the order are mainly predators. Certain species of the family Congridae make vertical burrows in sand. They live in large social groups, forming “eel gardens.” Some, such as the family Synaphobranchidae, inhabit depths of 3,000–4,000 m.

Freshwater eels, which belong to the family Anguillidae, live in fresh water from the immature stage until they reach sexual maturity and enter the open sea for spawning. The single genus, Anguilla, includes ten species that are found in the basins of the Atlantic, Indian, and Pacific oceans. Best known is the European eel (Anguilla anguilla), which inhabits fresh waters of Europe from the basin of the White Sea to the Black Sea, as well as North Africa. Usually the females head upstream, while the males continue to feed in river mouths. The eels are voracious predators that hunt at night. After living in a river or lake from five to 25 years, they swim down to the sea and, after covering a distance of 4,000–7,000 km, spawn in the Sargasso Sea at depths of 400 m and water temperatures of 16°-17°C. After spawning, the eels die, while the larvae drift with the currents to the coasts of Europe for 2½ to three years. After attaining a length of 75 mm, the larvae undergo metamorphosis and turn into 65-mm-lohg elvers that enter rivers. Freshwater eels are an important food fish.


Nikol’skii, G. V. Chastnaia ikhtiologiia. Moscow, 1971.
Zhizn’ zhivotnykh, vol. 4, part 1. Moscow, 1971.


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
There was not a predominant species represented in the Batoidea group, whereas 82% of the Anguilliformes were represented by the king snake eel, Ophichthus rex (Table 1).
The factors region and hook were only significant for Anguilliformes and Lutjanidae, respectively (Table 2).
The order Anguilliformes is usually considered a monophyletic group, and the well-supported grouping of the anguilliform genera Conger and Anguilla (with a bootstrap value of 91%) is thus expected (see e.g.
Eastern Gulf of Mexico Serranid Red grouper 68.1% Other 12.1% Yellowedge grouper 7.3% Black grouper 6.3% Gag grouper 6.1% Mid Atlantic Bight Other 30.2% Butterfly ray 21.4% Stingray 20.3% Roughtail stingray 15.4% Clearnose skate 12.6% Eastern Gulf of Mexico Anguilliformes Unknown eel King snake eel 19% Conger eel 6% Other 6% Spotted moray 4.3% S.E.
Occurrence of Thalassenchelys coheni (Anguilliformes; Chlopsidae) in the west Pacific Ocean.
Guide to the leptocephali (Elopiformes, Anguilliformes and Notacanthiformes).
1913 [END] [DC, *] Familia Myliobatidae Aetobatus narinari (Euphrasen, 1790) [COS] [BT, *] Myliobatis longirostris Applegate y Fitch, 1964 [END] [*] Familia Mobulidae Manta birostris (Donndorff, 1798) [CT] [SR, *] Clase Osteichthyes Orden Anguilliformes Familia Muraenidae Anarchias galapagensis (Seale, 1940) [EP] [BT, OO] [1] Echidna nebulosa (Ahl, 1789) [IP] [OO, *] Echidna nocturna (Cope, 1872) [EP] [OO, *] Enchelycore octaviana (Myers y Wade, 1941) [EP] [BT, OO] [1] Gymnomuraena zebra (Shaw, 1797) [IP] [BT, TH, DC, OO, *] [E] [1] Gymnothorax castaneus (Jordan y Gilbert, 1882) [EP] [BT, TH, OO, *] Gymnothorax panamensis (Steindachner, 1876) [EP] [BT, OO, *] [1] Muraena lentiginosa Jenyns, 1892 [EP] [BT, OO.