Difference between revisions of "Gar" - New World Encyclopedia
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''[[Lepisosteus platyrhincus]]'' | ''[[Lepisosteus platyrhincus]]'' | ||
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| − | '''Gar''' | + | '''Gar''' is the common name for any of the mainly freshwater, heavily armored [[fish]] comprising the family '''Lepisosteidae''' in the [[bony fish]] order Lepisosteiformes (or Semionotiformes), characterized by an elongated body and jaws, heavy ganoid scales, and needlelike teeth. Also known as gar pike or garfishes (ITIS 2004d, 2004e), they are one of only five living families in [[Actinopterygii]] (ray-finned fish) that are not included among the teleosts (Division Teleostei, modern bony fish) (Grande 2008). With fragments of [[fossil]]s tracing to the [[Cretaceous]], and complete skeletons known as far back as 110 million years ago, gars often are referred to as "living fossils" (Grande 2008). |
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| + | Gars inhabit freshwater, occasionally brackish water, and very rarely marine water in eastern | ||
| + | eastern [[North America]], [[Central America]], and the [[Caribbean]] islands (Nelson 1994; Sterba 1962). The family includes seven living species of fish in two [[genus|genera]]. | ||
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| + | ==Description== | ||
| + | [[Image:Gar shedd.jpg|thumb|left|Large gar at the [[Shedd Aquarium]]]]Gar bodies are elongated, heavily armored with [[Scale (zoology)#Ganoid scales| ganoid scale]]s, and fronted by similarly elongated [[jaw]]s filled with long sharp teeth. Tails are [[heterocercal]], and the [[dorsal fin]]s are close to the tail. As their vascularised [[Gas bladder|swim bladders]] can function as lungs, most gar surface periodically to take a gulp of air, doing so more frequently in [[stagnant (water)|stagnant]] or warm water when the concentration of oxygen in the water is low. As a result, they are extremely hardy and able to tolerate conditions that would kill most other fish. | ||
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| + | All the gars are relatively big fish, but the alligator gar ''Atractosteus spatula'' is the champion, as specimens having been recorded up to 3 meters in length.<ref>{{cite web|url=http://www.fishbase.org/summary/SpeciesSummary.php?id=1073|title=Atractosteus spatula - Alligator gar|accessdate=2007-07-19}}</ref> Even the smaller species, such as ''Lepisosteus oculatus'', are large, commonly reaching lengths of over 60 cm (2 feet), and sometimes much more.<ref>Kodera H. ''et al''.: Jurassic Fishes. TFH, 1994, ISBN 0-793800-86-2</ref> | ||
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The gars are members of the '''Lepisosteiformes''' (or '''Semionotiformes'''), an ancient order of "primitive" [[ray-finned fish]]; [[fossil]] gars are known from the [[Permian]] onwards. Their primitive traits are their very hard armour-like ganoid scales, a [[swimming bladder]] open to the [[pharynx]] that can function as a [[lung]] and the heterocercal tail. Fossil gars are found in both Europe and North America, indicating that in times past these fish had a wider distribution than they do today. Gars are considered to be a remnant of a group of rather primitive [[Osteichthyes| bony fish]] that flourished in the [[Mesozoic]], and are most closely related to the [[bowfin]], another archaic fish now found only in North America. | The gars are members of the '''Lepisosteiformes''' (or '''Semionotiformes'''), an ancient order of "primitive" [[ray-finned fish]]; [[fossil]] gars are known from the [[Permian]] onwards. Their primitive traits are their very hard armour-like ganoid scales, a [[swimming bladder]] open to the [[pharynx]] that can function as a [[lung]] and the heterocercal tail. Fossil gars are found in both Europe and North America, indicating that in times past these fish had a wider distribution than they do today. Gars are considered to be a remnant of a group of rather primitive [[Osteichthyes| bony fish]] that flourished in the [[Mesozoic]], and are most closely related to the [[bowfin]], another archaic fish now found only in North America. | ||
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==Ecology== | ==Ecology== | ||
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* Nelson, J. S., E. J. Crossman, H. Espinosa-Pérez, L. T. Findley, C. R. Gilbert, et al., eds. 2004. Common and scientific names of fishes from the United States, Canada, and Mexico. ''American Fisheries Society Special Publication'', no. 29. | * Nelson, J. S., E. J. Crossman, H. Espinosa-Pérez, L. T. Findley, C. R. Gilbert, et al., eds. 2004. Common and scientific names of fishes from the United States, Canada, and Mexico. ''American Fisheries Society Special Publication'', no. 29. | ||
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| + | <ref>Sterba, G: Freshwater Fishes of the World, p. 609, Vista Books, 1962</ref> | ||
==External links== | ==External links== | ||
Revision as of 23:22, 22 May 2008
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Atractosteus spatula |
Gar is the common name for any of the mainly freshwater, heavily armored fish comprising the family Lepisosteidae in the bony fish order Lepisosteiformes (or Semionotiformes), characterized by an elongated body and jaws, heavy ganoid scales, and needlelike teeth. Also known as gar pike or garfishes (ITIS 2004d, 2004e), they are one of only five living families in Actinopterygii (ray-finned fish) that are not included among the teleosts (Division Teleostei, modern bony fish) (Grande 2008). With fragments of fossils tracing to the Cretaceous, and complete skeletons known as far back as 110 million years ago, gars often are referred to as "living fossils" (Grande 2008).
Gars inhabit freshwater, occasionally brackish water, and very rarely marine water in eastern eastern North America, Central America, and the Caribbean islands (Nelson 1994; Sterba 1962). The family includes seven living species of fish in two genera.
Description
Gar bodies are elongated, heavily armored with ganoid scales, and fronted by similarly elongated jaws filled with long sharp teeth. Tails are heterocercal, and the dorsal fins are close to the tail. As their vascularised swim bladders can function as lungs, most gar surface periodically to take a gulp of air, doing so more frequently in stagnant or warm water when the concentration of oxygen in the water is low. As a result, they are extremely hardy and able to tolerate conditions that would kill most other fish.
All the gars are relatively big fish, but the alligator gar Atractosteus spatula is the champion, as specimens having been recorded up to 3 meters in length.[1] Even the smaller species, such as Lepisosteus oculatus, are large, commonly reaching lengths of over 60 cm (2 feet), and sometimes much more.[2]
Etymology
In British English the name gar was originally used for a species of needlefish, Belone belone, found in the North Atlantic, itself likely named after the Old English word gar meaning "spear".[3] Belone belone is now more commonly referred to as the "garpike" or "gar fish" to avoid confusion with the North American gars of the family Lepisosteidae.[4]
The genus name Lepisosteus comes from the Greek lepis meaning "scale" and osteon meaning "bone".[5] Atractosteus is similarly derived from Greek, in this case from atraktos, meaning "arrow".[6]
Distribution
The gars are members of the Lepisosteiformes (or Semionotiformes), an ancient order of "primitive" ray-finned fish; fossil gars are known from the Permian onwards. Their primitive traits are their very hard armour-like ganoid scales, a swimming bladder open to the pharynx that can function as a lung and the heterocercal tail. Fossil gars are found in both Europe and North America, indicating that in times past these fish had a wider distribution than they do today. Gars are considered to be a remnant of a group of rather primitive bony fish that flourished in the Mesozoic, and are most closely related to the bowfin, another archaic fish now found only in North America.
Ecology
Gar tend to be slow moving fish except when striking at their prey. They prefer the shallow and weedy areas of rivers, lakes, and bayous often congregating in small groups.[7] They are voracious predators, catching their prey with their needle-like teeth, obtaining with a sideways strike of the head.[8] Gar feed extensively on smaller fish and invertebrates such as crabs.[9] Gar are found across eastern North America from Costa Rica to southern Quebec (for example Lepisosteus osseus).[10] Although gar are primarily found in freshwater habitats several species enter brackish waters and a few, most notably Atractosteus tristoechus, are sometimes found in the sea.[11][12]
Significance to humans
Gar flesh is edible, and sometimes available in markets, but unlike the sturgeon that they resemble, their eggs (roe) are poisonous. Several species are traded as aquarium fish.[13]
Cultural Significance
The Gar fish is of considerable significance to Native American peoples of the southeastern United States where the gar figures prominently in ceremonial life and music. See Creek, Seminole
Gar in aquaria
Gar are popular fish for public aquaria where they are often kept alongside other large, "archaic" fish such as sturgeon and paddlefish. However, a few species, most commonly Lepisosteus oculatus, are sometimes offered to aquarists as pets. They do of course need very large tanks but in all other regards they are easy to keep. They are not much bothered by water quality or chemistry, and are tolerant of a wide range of temperatures. Gar must be allowed to breathe air, so some clearance between the surface of the water and the hood is essential.[14][15]
Gar get along well with any other fish that is too big to be eaten (such as large catfish, cichlids, and centrachids). They do not like aggressive tankmates, and despite being predators are essentially peaceable, sociable fish that do well with their own kind. Sturdy aquarium plants and bogwood can also be used to create hiding places, since gars are very fond of lurking in slightly shady regions.[16]
Feeding presents no problems. Most will take all kinds of meaty foods, including mealworms, crickets, earthworms, frozen lancefish and shrimps (defrosted), and strips of squid. Oily fish (like salmon and mackerel) as well as fish guts will quickly pollute an aquarium but are very effective at tempting newly introduced specimens to eat. Once settled in many specimens will also eat floating pellets as well. There is no nutritional reason to feed gar live fish, and cheap feeder fish in particular tend to introduce parasites into an aquarium.[17]
Gar diversity
Genus Atractosteus:
- Alligator gar Atractosteus spatula (305 cm)
- Cuban gar Atractosteus tristoechus (200 cm)
- Tropical gar Atractosteus tropicus (125 cm)
Genus Lepisosteus:
- Spotted gar Lepisosteus oculatus (112 cm)
- Longnose gar Lepisosteus osseus (200 cm)
- Shortnose gar Lepisosteus platostomus (88 cm)
- Florida gar Lepisosteus platyrhincus (132 cm)
ReferencesISBN links support NWE through referral fees
- ↑ Atractosteus spatula - Alligator gar. Retrieved 2007-07-19.
- ↑ Kodera H. et al.: Jurassic Fishes. TFH, 1994, ISBN 0-793800-86-2
- ↑ Gar. Retrieved 2007-04-21.
- ↑ Common Names of Belone belone. Retrieved 2007-04-21.
- ↑ Genera reference detail. Retrieved 2007-04-21.
- ↑ Atractosteus Genera reference detail. Retrieved 2007-04-21.
- ↑ Family Lepisosteidae - Gars. Retrieved 2007-04-21.
- ↑ Kodera H. et al.: Jurassic Fishes. TFH, 1994, ISBN 0-793800-86-2
- ↑ Atractosteus spatula - Alligator gar. Retrieved 2007-07-19.
- ↑ Family Lepisosteidae - Gars. Retrieved 2007-04-21.
- ↑ Family Lepisosteidae - Gars. Retrieved 2007-04-21.
- ↑ Monks N. (editor): Brackish Water Fishes, pp 322-324. TFH 2006, ISBN 0-7938-0564-3
- ↑ Kodera H. et al.: Jurassic Fishes. TFH, 1994, ISBN 0-793800-86-2
- ↑ Kodera H. et al.: Jurassic Fishes. TFH, 1994, ISBN 0-793800-86-2
- ↑ Sterba, G: Freshwater Fishes of the World, p. 609, Vista Books, 1962
- ↑ Riehl R. & Baensch H: Aquarium Atlas (vol. 2), pp 210-214. Microcosm Ltd, 1997, ISBN 1-890087-06-8
- ↑ Monks N. (editor): Brackish Water Fishes, pp 322-324. TFH 2006, ISBN 0-7938-0564-3
- Grande, L. 2008. http://www.novelguide.com/a/discover/grze_04/grze_04_00254.html Lepisosteiformes (Gars)]. NovelGuide. Retrieved May 22, 2008.
- Agbayani, E. 2004. Family Lepisosteidae, Gars. FishBase. Retrieved May 22, 2008.
- Integrated Taxonomic Information System (ITIS). 2004a. Lepisosteidae. ITIS Taxonomic Serial No.: 161092. Retrieved May 22, 2008.
- Integrated Taxonomic Information System (ITIS). 2004b. Atractosteus Rafinesque, 1820. ITIS Taxonomic Serial No.: 201896. Retrieved May 22, 2008.
- Integrated Taxonomic Information System (ITIS). 2004c. Lepisosteus Lacepède, 1803. ITIS Taxonomic Serial No.: 161093. Retrieved May 22, 2008.
- Integrated Taxonomic Information System (ITIS). 2004d. Semionotiformes. ITIS Taxonomic Serial No.: 161090. Retrieved May 22, 2008.
- Integrated Taxonomic Information System (ITIS). 2004e. Lepisosteiformes. ITIS Taxonomic Serial No.: 650224. Retrieved May 22, 2008.
- Nelson, J. S. 1994. Fishes of the World, 3rd ed. New York: John Wiley & Sons. ISBN 0471547131.
- Nelson, J. S., E. J. Crossman, H. Espinosa-Pérez, L. T. Findley, C. R. Gilbert, et al., eds. 2004. Common and scientific names of fishes from the United States, Canada, and Mexico. American Fisheries Society Special Publication, no. 29.
External links
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- ↑ Sterba, G: Freshwater Fishes of the World, p. 609, Vista Books, 1962
