Difference between revisions of "Eel" - New World Encyclopedia

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{{Taxobox
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| color = pink
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| name = True eels
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| image = anguillarostratakils.jpg
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| image_width = 260px
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| image_caption = [[American eel]], ''Anguilla rostrata''
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| regnum = [[Animal]]ia
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| phylum = [[Chordate|Chordata]]
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| classis = [[Actinopterygii]]
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| superordo = [[Elopomorpha]]
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| ordo = '''Anguilliformes'''
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| subdivision_ranks = Suborders
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| subdivision = See text for suborders and families.
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}}
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'''Eel''' is the common name for any of the various members of the [[fish]] order '''Anguilliformes''', which are characterized by an elongated, [[snake]]-like body, the absence of pelvic fins, and typically without [[scale (zoology)|scales]] or with the scales embedded in the skin. Eels are generally marine or, as in the case of the freshwater eels (family Anguillidae),  catadromous, spawning in marine environments and with the young eels traveling back into freshwater.
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The common name eel is applied to some species in the freshwater family Electrophoridae (electric eels) of the order Gymnotiformes and in the largely freshwater order Synbranchifromes (including the swamp eels in family Synbranchidae and the spiny eels in family Mastacembelidae). However, the true eels are placed in order Anguilliformes.
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==Biology==
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===Description===
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Eels lack pelvic fins and the associated skeletal structures. The pectoral fins (in those species that have them) are midlateral in position and lack the posttemporal bone, which connects the shoulder girdle to the skull. The caudal and anal fins are long, usually connecting with the tail (caudal) fin. The caudal fin lacks rays or may be absent. The body is very elongated.
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The number of rays of the gill webbing ranges from 6 to 51, though sometimes they are absent altogether. The scales are [[Scale (zoology)#Ctenoid and cycloid scales|cycloid]] or absent.
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Depending on their species, eels can reach from 10 cm to 3 m, and weigh up to 65 kg.
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are an [[order (biology)|order]] of [[fish]], which consists of 4 suborders, 19 families, 110 genera and 400 species.  Most eels are predators.
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The flat and transparent [[larva]] of the eel is called a [[leptocephalus]]. A young eel is called an '''elver'''.
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Most eels prefer to dwell in shallow waters or hide at the bottom layer of the ocean, sometimes in holes. These holes are called eel pits. Only the [[Anguillidae]] family comes to fresh water to dwell there (not to breed). Some eels dwell in deep water (in case of family [[Synaphobranchidae]], this comes to a depth of 4,000 m), or are active swimmers (the family [[Nemichthyidae]] - to the depth of 500 m).
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The life cycle of the eel was a mystery for a very long time, because larval eels look very different from adult eels, and were thought to be a separate species.
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==Classification==
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[[Image:Moray eel kona.jpg|thumb|right|200px|A moray eel.]] [[image:rostrata.jpg|thumb|Juvenile [[American eel]]s]]
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[[Image:FH000014.jpg|thumb|[[Garden eel]]s]]
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<!-- Unsourced image removed: [[Image:Umbrellamouthgulpereel.jpg|thumb|[[Umbrella Mouth Gulper Eel]]s]] —>
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This classification follows [[FishBase]] in dividing the eels into fifteen families. Additional families that are included in other classifications (notably [[ITIS]] and [[Systema Naturae 2000]]) are noted below the family with which they are synomized in the FishBase system.
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==Fishing==
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Fishing for eels is best done at night with either a gaff or a strong line with a small and square bloody piece of red meat.
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Elvers were once eaten by fishermen as a cheap dish, but environmental changes have lead to increased rarity of the fish.  They are now considered a delicacy and are priced at up to £700 per kg in the UK.
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==Suborders and families==
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'''Suborder''' [[Anguilloidei]]
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*[[Anguillidae]] ([[freshwater eel]]s)
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*[[Chlopsidae]] ([[false moray]]s)
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*[[Heterenchelyidae]]
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*[[Moringuidae]] ([[spaghetti eel]]s)
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*[[Muraenidae]] ([[moray eel]]s)
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*[[Myrocongridae]]
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'''Suborder''' [[Congroidei]]
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*[[Colocongridae]]
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*[[Congridae]] ([[Congridae|conger]]s)
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**Including Macrocephenchelyidae
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*[[Derichthyidae]] ([[longneck eel]]s)
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**Including Nessorhamphidae
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*[[Muraenesocidae]] ([[conger pike]]s)
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*[[Nettastomatidae]] ([[witch eel]]s)
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*[[Ophichthidae]] ([[snake eel]]s)
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'''Suborder''' [[Nemichthyoidei]]
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*[[Nemichthyidae]] ([[snipe eel]]s)
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*[[Serrivomeridae]] ([[sawtooth eel]]s)
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'''Suborder''' [[Synaphobranchoidei]]
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*[[Synaphobranchidae]] ([[cutthroat eel]]s)
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**Including Dysommidae, Nettodaridae, and Simenchelyidae
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In some classifications the family [[Cyematidae]] of [[bobtail snipe eel]]s is included in the Anguilliformes, but in the FishBase system that family is included in the order [[Saccopharyngiformes]].
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The so-called "[[Electric Eel]]" of South America is not a true eel, but is more closely related to the [[Carp]].
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==Use by humans==
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Freshwater eels (''[[unagi]]'') and marine eels ([[Conger eel]], ''[[anago fish|anago]]'') are commonly used in [[Japanese cuisine]].  [[Unadon]] is a very popular but rather expensive food.  Eels are used in [[Cantonese cuisine|Cantonese]] and [[Shanghai cuisine]] too. The [[European eel]] and other freshwater eels are eaten in Europe, the United States, and other places around the world. A traditional [[East London, England|East London]] food is [[jellied eels]]. The [[Basque cuisine|Basque]] delicacy ''angulas'' consists of [[deep frying|deep-fried]] [[elvers|elver]].[http://www.buber.net/Basque/Food/food1.html]. [[New Zealand longfin eel]] is a traditional food for [[Maori]] in [[New Zealand]]. In [[Italian cuisine]] eels from the [[Comacchio]] area (a swampy zone along the [[Adriatic]] coast) are specially praised along with the freshwater ones of the [[Bolsena Lake]]. In northern [[Germany]], smoked eel is praised as a delicatesse.
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Eels are popular among marine aquarists in the [[United States]], particularly the [[Moray eel]] which is commonly kept in tropical saltwater aquariums.
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==Other Information==
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There is an urban legend that wallets made out of [[electric eel]]s (which, despite their name, are not eels) will demagnetize your [[credit card]]s. This was proven to be untrue in an episode of the [[Mythbusters]] TV show. Actually, as pointed out in the [[Straight Dope]], eel-skin wallets are made from [[hagfish]] which are unrelated to electric eels.[http://www.straightdope.com/classics/a3_388.html] Furthermore, it seems that magnetic clasps, not eel leather, are to blame for demagnetization.
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Eel blood is toxic.  The toxic protein it contains is destroyed by cooking.  The toxin derived from eel blood serum was used by [[Charles Robert Richet]] in his Nobel winning research which discovered [[anaphylaxis]] (by injecting it into dogs and observing the effect).
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On [[January 31]], [[1930]], the [[Denmark|Danish]] research ship; "The Dana", captured, (south of Africa's Cape of Good Hope), what they thought at the time was a six-feet long eel larva.  This could have meant there were very long eels in the sea, since the typical eel larva is three inches long, while the adults can grow from about 4 feet to 16 feet long.  In 1970, Dr. David G. Smith from the University of Miami, identified the larva found as that of the [[spiny eel]], an eel-like fish whose larvae length is equal to its adult length, while the larvae length of the true eel is much shorter than its adult length.  [http://www.strangemag.com/seaserpcarcsshuk.html]
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One of the famous attractions of the [[Pacific]] island of [[Huahine]] (part of the [[Society Islands]] in [[French Polynesia]]), is the bridge that crosses over a stream with 3- to 6-foot long eels.  These eels are deemed sacred by the locals, by local mythology.  Aside from just viewing these slithering creatures, any tourist can buy a can of mackerel and feed the eels.
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==See also==
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{{wiktionary}}
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*[[Eel ladder]]
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*[[American eel]]
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*[[Conger eel]]
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*[[European eel]]
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*[[Garden eel]]
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*[[Moray eel]]
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*[[Snowflake moray]]
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*[[Short-finned eel]]
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*[[Oily fish]]
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*[[Unadon]]
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*[[Spiny eel]], (an eel-like fish)
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*[[Vailulu'u]] (eel community at a [[hydrothermal vent]] in the Pacific Ocean)
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==References==
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* {{FishBase order|order = Anguilliformes|month = January|year = 2006}}
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[[Category:Life sciences]]
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[[Category:Animals]]
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[[Category:Fishes]]
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{{credit|Eel|160316983}}

Revision as of 22:28, 29 September 2007


True eels
American eel, Anguilla rostrata
American eel, Anguilla rostrata
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Superorder: Elopomorpha
Order: Anguilliformes
Suborders

See text for suborders and families.

Eel is the common name for any of the various members of the fish order Anguilliformes, which are characterized by an elongated, snake-like body, the absence of pelvic fins, and typically without scales or with the scales embedded in the skin. Eels are generally marine or, as in the case of the freshwater eels (family Anguillidae), catadromous, spawning in marine environments and with the young eels traveling back into freshwater.

The common name eel is applied to some species in the freshwater family Electrophoridae (electric eels) of the order Gymnotiformes and in the largely freshwater order Synbranchifromes (including the swamp eels in family Synbranchidae and the spiny eels in family Mastacembelidae). However, the true eels are placed in order Anguilliformes.


Biology

Description

Eels lack pelvic fins and the associated skeletal structures. The pectoral fins (in those species that have them) are midlateral in position and lack the posttemporal bone, which connects the shoulder girdle to the skull. The caudal and anal fins are long, usually connecting with the tail (caudal) fin. The caudal fin lacks rays or may be absent. The body is very elongated.

The number of rays of the gill webbing ranges from 6 to 51, though sometimes they are absent altogether. The scales are cycloid or absent.

Depending on their species, eels can reach from 10 cm to 3 m, and weigh up to 65 kg. 

are an order of fish, which consists of 4 suborders, 19 families, 110 genera and 400 species.  Most eels are predators.

The flat and transparent larva of the eel is called a leptocephalus. A young eel is called an elver.

Most eels prefer to dwell in shallow waters or hide at the bottom layer of the ocean, sometimes in holes. These holes are called eel pits. Only the Anguillidae family comes to fresh water to dwell there (not to breed). Some eels dwell in deep water (in case of family Synaphobranchidae, this comes to a depth of 4,000 m), or are active swimmers (the family Nemichthyidae - to the depth of 500 m).

The life cycle of the eel was a mystery for a very long time, because larval eels look very different from adult eels, and were thought to be a separate species.

Classification

A moray eel.
Juvenile American eels
File:FH000014.jpg
Garden eels

This classification follows FishBase in dividing the eels into fifteen families. Additional families that are included in other classifications (notably ITIS and Systema Naturae 2000) are noted below the family with which they are synomized in the FishBase system.

Fishing

Fishing for eels is best done at night with either a gaff or a strong line with a small and square bloody piece of red meat.

Elvers were once eaten by fishermen as a cheap dish, but environmental changes have lead to increased rarity of the fish. They are now considered a delicacy and are priced at up to £700 per kg in the UK.

Suborders and families

Suborder Anguilloidei

  • Anguillidae (freshwater eels)
  • Chlopsidae (false morays)
  • Heterenchelyidae
  • Moringuidae (spaghetti eels)
  • Muraenidae (moray eels)
  • Myrocongridae

Suborder Congroidei

  • Colocongridae
  • Congridae (congers)
    • Including Macrocephenchelyidae
  • Derichthyidae (longneck eels)
    • Including Nessorhamphidae
  • Muraenesocidae (conger pikes)
  • Nettastomatidae (witch eels)
  • Ophichthidae (snake eels)

Suborder Nemichthyoidei

  • Nemichthyidae (snipe eels)
  • Serrivomeridae (sawtooth eels)

Suborder Synaphobranchoidei

  • Synaphobranchidae (cutthroat eels)
    • Including Dysommidae, Nettodaridae, and Simenchelyidae

In some classifications the family Cyematidae of bobtail snipe eels is included in the Anguilliformes, but in the FishBase system that family is included in the order Saccopharyngiformes.

The so-called "Electric Eel" of South America is not a true eel, but is more closely related to the Carp.

Use by humans

Freshwater eels (unagi) and marine eels (Conger eel, anago) are commonly used in Japanese cuisine. Unadon is a very popular but rather expensive food. Eels are used in Cantonese and Shanghai cuisine too. The European eel and other freshwater eels are eaten in Europe, the United States, and other places around the world. A traditional East London food is jellied eels. The Basque delicacy angulas consists of deep-fried elver.[1]. New Zealand longfin eel is a traditional food for Maori in New Zealand. In Italian cuisine eels from the Comacchio area (a swampy zone along the Adriatic coast) are specially praised along with the freshwater ones of the Bolsena Lake. In northern Germany, smoked eel is praised as a delicatesse.

Eels are popular among marine aquarists in the United States, particularly the Moray eel which is commonly kept in tropical saltwater aquariums.

Other Information

There is an urban legend that wallets made out of electric eels (which, despite their name, are not eels) will demagnetize your credit cards. This was proven to be untrue in an episode of the Mythbusters TV show. Actually, as pointed out in the Straight Dope, eel-skin wallets are made from hagfish which are unrelated to electric eels.[2] Furthermore, it seems that magnetic clasps, not eel leather, are to blame for demagnetization.

Eel blood is toxic. The toxic protein it contains is destroyed by cooking. The toxin derived from eel blood serum was used by Charles Robert Richet in his Nobel winning research which discovered anaphylaxis (by injecting it into dogs and observing the effect).

On January 31, 1930, the Danish research ship; "The Dana", captured, (south of Africa's Cape of Good Hope), what they thought at the time was a six-feet long eel larva. This could have meant there were very long eels in the sea, since the typical eel larva is three inches long, while the adults can grow from about 4 feet to 16 feet long. In 1970, Dr. David G. Smith from the University of Miami, identified the larva found as that of the spiny eel, an eel-like fish whose larvae length is equal to its adult length, while the larvae length of the true eel is much shorter than its adult length. [3]

One of the famous attractions of the Pacific island of Huahine (part of the Society Islands in French Polynesia), is the bridge that crosses over a stream with 3- to 6-foot long eels. These eels are deemed sacred by the locals, by local mythology. Aside from just viewing these slithering creatures, any tourist can buy a can of mackerel and feed the eels.

See also

  • Eel ladder
  • American eel
  • Conger eel
  • European eel
  • Garden eel
  • Moray eel
  • Snowflake moray
  • Short-finned eel
  • Oily fish
  • Unadon
  • Spiny eel, (an eel-like fish)
  • Vailulu'u (eel community at a hydrothermal vent in the Pacific Ocean)

References
ISBN links support NWE through referral fees

  • "Anguilliformes". FishBase. Ed. Ranier Froese and Daniel Pauly. January 2006 version. N.p.: FishBase, 2006.

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