Alligator gar

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Alligator gar
captive Alligator Gar
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Lepisosteiformes
Family: Lepisosteidae
Genus: Atractosteus
Species: A. spatula
Binomial name
Atractosteus spatula
(Lacépède, 1803)
Synonyms

Lepisosteus spatula Lacépède, 1803
Atractosteus adamantinus Rafinesque, 1818

The alligator gar, Atractosteus spatula, is a primitive ray-finned fish. They are related to bowfin in the superorder Holestei (ho'-las-te-i). Gars are living fossils that have remained relatively unchanged since their earliest beginnings. Fossilized remains of gar trace back over a million years to the age of dinosaurs during the early Cretaceous.

Unlike other gar species, the mature alligator gar has a dual row of large teeth in the upper jaw which they use for impaling and holding prey. They are primarily piscivores, but are known to eat water fowl and small mammals floating on the water's surface. Its common name was derived from its resemblance to the American alligator, particularly its broad snout and long sharp teeth. The body of the alligator gar is torpedo shaped which serves them well as ambush predators that rely on sudden bursts of speed to capture prey. The dorsal surface of the alligator gar is a brown or olive color, while the ventral surface tends to be lighter, a combination which provides the perfect camouflage for the turbid, and sometimes brackish waters they inhabit.

Alligator gar have been extirpated from much of their natural range because of habit destruction. They are now found primarily in the southern portions of the United States extending into Mexico. There are ongoing restoration projects by various state and federal resource agencies in an effort to reintroduce alligator gar into their native habitats. Restocking programs have included the Ohio River, and various locations in Illinois, Missouri, Arkansas, and Kentucky.

Anatomy and Physiology[edit]

Along with its status as the largest species of gar, the alligator gar is one of the largest freshwater fishes found in North America. It can grow 8 to 10 ft (2.4 to 3.0 m) in length, and weigh over 300 lb (140 kg) at maturity. The world record alligator gar was inadvertently caught in the net of fisherman, Kenny Williams of Vicksburg, Mississippi while he was fishing the oxbow lakes of the Mississippi River on Valentine's Day, February 14, 2011. According to news reports, Williams was pulling up his net on Lake Chotard expecting to find his quota of buffalo fish. Instead, he discovered a large alligator gar tangled in the net. The gar was 8 ft 5 −18 in (2.562 m) long, weighed 327 lb (148 kg), and its girth was 47 in (120 cm). According to wildlife officials, the age of the fish was estimated to be somewhere between 50 and 70 years old. Williams donated the fish to the Mississippi Museum of Natural Science in Jackson where it will remain on display. [1] [2]

Alligator gars have gills, but unlike other fish they also have a swim bladder lung that runs the full length of their body. The bladder not only provides buoyancy, it enables them to breathe air which is why they are able to inhabit bodies of water where most other fishes would die of suffocation. The bladder is connected to their mouth through a small schematic duct that allows them to breathe or gulp air when they break the surface, an action that is seen quite frequently on lakes in the southern United States during the heat of summer. Alligator gars do not have scales like other fish, rather their bodies are armored with overlapping ganoid scales that are diamond-shaped, and composed of a hard enamel-like bony substance that is nearly impenetrable. [3]

Behavior[edit]

A large alligator gar caught in Moon Lake

Feeding[edit]

The alligator gar is a relatively passive, seemingly sluggish solitary fish that inhabits freshwater, but can also tolerate high salinities. They are voracious predators when in ambush of their prey. Their method of attack is to lay still in the water, and wait for an unsuspecting fish to swim within reach. They lunge forward, and with a sweeping motion can impale their prey with their double rows of sharp teeth. Alligator gar are also opportunistic night predators, and will prey on small mammals, turtles, and waterfowl that may be floating on the water's surface.[3]

Breeding[edit]

Though the alligator gar prefers slow-moving waters of rivers, bayous, and oxbows throughout most of the year, it appears to need springtime inundated floodplain fields or wetland vegetation to spawn.[4] Egg production is variable, and believed to be dependent on the size of the female. A common formula is 4.1 eggs per gram of body weight, or an average of 150,000 eggs per spawn. Alligator gar eggs are bright red, and highly toxic if eaten.[3]

Taxonomy[edit]

Lacépède first described the alligator gar in 1803. The original name was Lepisosteus spatula, but was later changed by E. O. Wiley in 1976 to Atractosteus spatula in order to recognize two distinct extant genera of gars. Synonyms of Atractosteus spatula include Lesisosteus [sic] ferox (Rafinesque 1820), and Lepisosteus spatula (Lacepede 1803). Fossils from the order Lepisosteiformes have been collected in Europe from the Cretaceous to Oligocene periods, in Africa and India from the Cretaceous, and in North America from the Cretaceous to recent. Lepisosteidae is the only extant family of gar which has seven species all located in North and Central America.[5]

Distribution[edit]

Natural[edit]

Alligator gars are commonly found in the warm, sluggish backwaters of lowland rivers and lakes, in swamps, reservoirs, brackish waters, bayous and bays in the Southern United States. They are known to enter coastal bays, and have been seen in the Gulf of Mexico. In Louisiana it is common to see large gar breaking the surface in brackish marshes. They are found throughout the lower Mississippi River Valley and Gulf Coast states of the Southern United States and Mexico as far south as Veracruz, encompassing the following US states: Texas, Oklahoma, South Carolina, North Carolina, Virginia, Louisiana, Kentucky, Mississippi, Alabama, Tennessee, Arkansas, Missouri, Florida, and Georgia.[6] They have also been known historically to come as far north as central Kansas, Nebraska, Ohio, Iowa, and west-central Illinois, where the most northerly verified catch was at Meredosia, Illinois, in 1922. The specimen now preserved was caught at nearby Beardstown, and measured 8.5 ft (2.6 m) in length.[7] Specimens at locations further south in Illinois have been verified as recently as 1976, with the Illinois Academy of Sciences verifying a total of 122 captures to that date.[7]

Outside natural range[edit]

A few notable sightings of alligator gar have been reported outside North America.

In November 2008, an alligator gar measuring 0.5- to 0.6-m in length was caught in the north of Esenguly, Turkmenistan by two officials of Turkmenistan Fishery Protection. Dr. R. Mayden, Saint Louis University and Dr. Eric Hilton, Virginia Institute of Marine Science confirmed it was Atractosteus spatula.[8]

On September 4, 2009 a meter-long alligator gar was found in Tak Wah Park in Tsuen Wan, Hong Kong. In the next two days, at least 16 other alligator gar, with the largest one measuring 1.5 m (4.9 ft) in length, were found in ponds in public parks in Hong Kong.[9] As reported by nearby residents, the fish were released in the ponds by aquarium hobbyists, and had lived there for several years. However, after a complaint made by a citizen who falsely identified the fish as crocodiles, the use of terms like "Horrible Man-eating Fish" were appearing in the headlines of some major local newspapers. Government officials removed all the fish from the ponds claiming the species had no conservation value, and would negatively affect the local ecology if left in the ponds.[10]

On January 21, 2011, a 1.5-m alligator gar was caught at a canal in Pasir Ris, Singapore, by two recreational fishermen. The fish was taken to a nearby pond where the owner confirmed it as an alligator gar, not an arapaima as the men initially thought.[11]

Alligator gar have also recently become "trophy" fish for private aquariums, particularly in Japan. In June 2011, a group of men from Florida and Louisiana were indicted on charges of illegally removing wild gar from the Trinity River in Texas, and attempting to ship the fish to Japan at the behest of private collectors. The largest of the fish allegedly could have fetched $40,000 in the Japanese black market.[12]

Human utilization[edit]

Sport fish[edit]

This six-foot. 129-pound alligator gar was caught in the Brazos River in Texas.

Oklahoma, Texas, Arkansas, Mississippi, and Louisiana allow regulated sport fishing of the alligator gar.

The world record for the largest alligator gar caught on rod and reel is 279 lb (127 kg).[Note 1][13] The largest taken by bowfishing is 365 lb (166 kg).[Note 2][14]

Alligator gar are popular among bowfishers because of its size and tendency to fight. An interesting anatomical feature of this fish is its buoyancy bladder is directly connected to its throat, giving it the ability to draw in air from above the water. For this reason, alligator gar are often found near the surface of a body of water.

Food source[edit]

In several Southern US states, alligator gar are harvested commercially because of their high yield of white meat filets. The meat is sold to wholesale distributers, and is also sold retail by a select few supermarkets where prices can easily bring $3.00/lb. Fried gar balls, grilled and boiled fillets are quite popular in the south.[3]

Aquaria[edit]

Despite their large adult size, alligator gar are kept as aquarium fish, although many fish labelled as "alligator gar" in the aquarium trade are actually smaller species. This fish requires a very large aquarium or pond and ample resources to keep. They are also popular fish for public aquariums. True gars are illegal as pets in multiple areas but will occasionally show up in fish stores.

Historically[edit]

Early American settlers tanned the skins of gars, and used them to cover their wooden plows. Native Americans utilized the ganoid scales for arrow heads, various tools, and ornamentation such as necklaces.[3]

Notes[edit]

  1. ^ Caught by Bill Valverde, January 1, 1951, Rio Grande, Texas.
  2. ^ Caught by Kirk Kirkland, 1991, in Texas.

References[edit]

  1. ^ "Vicksburg Man Catches 327 Lb. Alligator Gar". WAPT News. February 18, 2011. 
  2. ^ Chad Love (February 23, 2011). "World Record Alligator Gar Pulled From Mississippi Lake Tangled in Fisherman's Net". Field & Stream. Retrieved April 19, 2014. 
  3. ^ a b c d e "Alligator Gar". Earthwave Society. Retrieved April 14, 2014. 
  4. ^ "Gator gars under watchful eye of state wildlife department". Your Houston News. November 22, 2010. 
  5. ^ Nathaniel Goddard. "Alligator Gar". FLMNH Ichthyology Department. Retrieved April 19, 2014. 
  6. ^ "Alligator Gar Technical Committee". Southern Division of the American Fisheries Society. Retrieved May 17, 2013. 
  7. ^ a b Poly, William J. (2001). "Distribution of the Alligator Gar, Atractosteus spatula (Lacépède, 1803), in Illinois". Transactions of the Illinois State Academy of Science 94 (3): 185–190. 
  8. ^ "Hazar Deňziniň Türkmen Kenarynda Amerikan Sowutly Çortanyň Tutulmagynyň Ilkinji Wakasy" (in Turkish). Türkmenistanyò Tebigaty goramak ministrligi. Retrieved May 17, 2013. 
  9. ^ "Monster exotic fish found in Hong Kong ponds". AFP. September 5, 2009.
  10. ^ Nip, Amy (September 6, 2009). "Dumped fish prove to be slippery customers during pond clearance". South China Morning Post.
  11. ^ "Friends catch 1.5m 'monster' fish from Pasir Ris canal after long struggle". The Straits Times. January 21, 2011. 
  12. ^ Horswell, Cindy (June 17, 2011). "Indictments accuse 3 of taking alligator gar fish out of Trinity". Houston Chronicle. 
  13. ^ "State Freshwater Records: Rod and Reel". Texas Parks & Wildlife. Retrieved May 17, 2013. 
  14. ^ "Alligator Gar". Texas Fishing Guides. Retrieved May 17, 2013. 

External links[edit]