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

 
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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 which trace back to the early Cretaceous, over a hundred million years ago.

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.

For the past half century, alligator gar were incorrectly perceived as a nuisance species, and targeted for elimination by state and federal authorities in the United States. They have been extirpated from much of their historic range due to habitat destruction, indiscriminate culling, and unrestricted harvests. Populations are now found primarily in the southern portions of the United States extending into Mexico. Over the past decade, opinions and attitudes have changed regarding the importance of alligator gar to the ecosystems they inhabit. As a result, they have been afforded protection by restricted licensing, and under the Lacey Act which makes it illegal to transport fish in interstate commerce in violation of state law or regulation. Several state and federal resource agencies are monitoring populations, and have initiated outreach programs to educate the public on the importance of alligator gar. There are also restoration projects underway to reintroduce alligator gar into their native habitats.

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]

Gill of a juvenile gar

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 hot summer months. 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]

Feeding Behavior[edit]

The alligator gar is a relatively passive, seemingly sluggish solitary fish that inhabits freshwater, but can also tolerate high salinities. Their method of attack is to lay still in the water, appearing as harmless as a floating log while they wait for an unsuspecting fish to swim within reach. They are voracious predators when in ambush of their prey. They lunge forward, and with a sweeping motion grab their prey, impaling it onto 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]

The majority of diet studies have shown alligator gar to be opportunistic piscivores that occasionally ingest sport fishes, but feed primarily on non-sport species as well as invertebrates, and birds. Diet studies have also revealed fishing tackle and boat engine parts in the stomach contents.[4]

A large alligator gar caught in Moon Lake

Spawning[edit]

As with most ancestral species, alligator gars are long lived, and sexually late maturing. Most females do not reach sexual maturity until after their first decade of life while males reach sexual maturity in half that time. The conditions for spawning must be precise for a successful spawn to occur. Preparation for spawning begins in the spring with the extended photo period and rising water temperatures, but flooding is also necessary to trigger the event. When the rivers rise and spread over the floodplain, it creates oxbows and sloughs along the river, and inundates terrestrial vegetation which in turn provides protection and nutrient rich habitat for larval fishes, and fry. Once the water temperature has reached 68 to 82 °F (20 to 28 °C), and all the other required events have occurred at the precise time, gars will move into the grassy, weed laden shallows to spawn.[5]

Actual spawning occurs when a collection of males gather around gravid females, and begin writhing, twisting, bumping into and slithering over the tops of females, an activity which triggers the release of eggs. At the same, males release clouds of milt to fertilize the eggs as they are released into the water column. The sticky eggs then attach to submerged vegetation, and development begins. It takes only a few days for the eggs to hatch into larval fish, and another ten days or so for the larval fish to detach from the vegetation and start making their way as young fry.[5] 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.[6]

Human utilization[edit]

Early History[edit]

Native Americans in the south, and Caribbean peoples used the alligator gar's ganoid scales for arrow heads, breastplates, and as a shield to cover plows. Early Americans tanned the skins to make a strong, durable leather to cover their wooden plows, make purses, and various other items. Gar oil was also used by the people of Arkansas as a repellant against buffalo-gnats.[4] The meat of the alligator gar is white, firm, and quite flavorful.

Alligator gar fillets on the grill, and boiled in crab boil
1995 Choke Canyon Gar Harvest

For decades, alligator gar were perceived as a nuisance fish by state and federal authorities who targeted them for elimination to protect game fish populations, and to prevent alleged attacks on humans, a claim that remains unsubstantiated. Fishermen also participated in the slaughter of thousands of alligator gar all the while believing they were providing a great service. In 1995, KUHT channel 8, a member PBS television station located on the campus of the University of Houston in Houston, Texas, distributed and broadcast the first video documentary ever produced on alligator gar. The documentary, "Alligator Gar:Predator or Prey?", debuted nationally in prime time during the July Sweeps, and was the number one rated program of the evening for KUHT, and several other member PBS stations. The documentary focused on the physiology and life history cycle of alligator gar, addressed the destruction of habitat, the unregulated culling and over harvesting of alligator gar from various lakes in Texas and Louisiana, and expressed concern for the future of the species at a time when it was still considered a "trash fish".[3] A decade passed before any significant action was taken to protect and preserve the remaining populations of alligator gar in the United States. The Missouri Department of Conservation has since partnered with Tennessee, Arkansas, Kentucky, Illinois, Alabama, Mississippi, Texas, Oklahoma, and Louisiana in restoration and management activities.[4]

Market display of gar fillets
On site processing of alligator gar harvest

Commercialization[edit]

Because of the declining populations of alligator gar throughout its historic range, commercial harvest is being regulated, and closely monitored. Alligator gar have a high yield of white meat filets and a small percentage of waste relative to body weight. 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 fillets, and fillets boiled in water with crab boil seasoning are popular dishes in the south. There is also a small cottage industry that makes jewelry out of ganoid scales, and also tans gar hides to produce leather for making lamp shades, purses, and a host of novelty items.[3]

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

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.

Alligator gar are highly prized and sought after for private aquariums, particularly in Japan. According to reports, large alligator gar could fetch as much as $40,000 in the Japanese black market.[7] In June 2011, three 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 indictments resulted from an undercover sting operation by special agents with the U.S. Fish & Wildlife Service, the Texas Parks and Wildlife Department, and the Florida Fish and Wildlife Conservation Commission.[8] The charges included violations of three separate provisions of the Lacey Act, specifically conspiracy to submit a false label for fish transported in interstate commerce, conspiracy to transport fish in interstate commerce in violation of state law or regulation; and conspiracy to transport and sell fish in interstate commerce in violation of state law or regulation.[9] Two of the conspirators pled guilty to one count, and the government dropped the other two charges against them. A third conspirator went to trial on all three counts, was acquitted on one count, and found guilty on two. The district court sentenced him to serve nine months in prison followed by one year of supervised release.[10] The case was appealed, and on April 15, 2014, the appellate court affirmed the judgment of the district court.[11]

Sport fish[edit]

The long time public perception of the alligator gar as a trash fish has changed with increasing national and international attention as a sport fish which some have attributed to features on popular television shows. Oklahoma, Texas, Arkansas, Mississippi, and Louisiana allow regulated sport fishing of the alligator gar. Texas has one of the best remaining fisheries for alligator gar, and in concert with its conservation efforts to maintain a viable fishery, imposed a one-per-day bag limit on alligator gar in 2009.[12] The world record for the largest alligator gar caught on rod and reel is 279 lb (127 kg).[Note 1][13] Alligator gar are also quite popular among bowfishers because of their large size, trophy potential, and fighting ability. The largest taken by bowfishing is 365 lb (166 kg).[Note 2][14]

Distribution[edit]

Natural[edit]

Alligator gars use a wide variety of aquatic habitats, but most 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.[3] 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.[15] Historical distribution has recorded them 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 which has long since been preserved was caught at nearby Beardstown, and measured 8.5 ft (2.6 m) in length. 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.[16]

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.[17]

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.[18] 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.[19]

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.[20]

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 f "Alligator Gar". Earthwave Society. Retrieved April 14, 2014. 
  4. ^ a b c "Missouri Alligator Gar Management and Restoration Plan". Missouri Department of Conservation Fisheries Division. January 22, 2013. 
  5. ^ a b Shannon Thompkins (April 19, 2014). "Once a nuisance, alligator gar increasingly protected". Houston Chronicle. 
  6. ^ Nathaniel Goddard. "Alligator Gar". FLMNH Ichthyology Department. Retrieved April 19, 2014. 
  7. ^ Horswell, Cindy (June 17, 2011). "Indictments accuse 3 of taking alligator gar fish out of Trinity". Houston Chronicle. 
  8. ^ Jon Berstein (October 15, 2011). "Monster fish tale: Alligator gar sting ends in conviction". SunSentinel. 
  9. ^ "Accused alligator gar smugglers busted in trinity river operation". ABC 9 KTRE. 2011. 
  10. ^ "Monthly Bulletin". Regional EnvironmentalEnforcement Association. October 2012. Retrieved April 2014. 
  11. ^ "Opinions". U.S. Court of Appeals. April 15, 2014. 
  12. ^ "Alligator Gar". Texas Parks and Wildlife Department. Retrieved April 21, 2014. 
  13. ^ "State Freshwater Records: Rod and Reel". Texas Parks & Wildlife. Retrieved May 17, 2013. 
  14. ^ "Alligator Gar". Texas Fishing Guides. Retrieved May 17, 2013. 
  15. ^ "Alligator Gar Technical Committee". Southern Division of the American Fisheries Society. Retrieved May 17, 2013. 
  16. ^ 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. 
  17. ^ "Hazar Deňziniň Türkmen Kenarynda Amerikan Sowutly Çortanyň Tutulmagynyň Ilkinji Wakasy" (in Turkish). Türkmenistanyò Tebigaty goramak ministrligi. Retrieved May 17, 2013. 
  18. ^ "Monster exotic fish found in Hong Kong ponds". AFP. September 5, 2009.
  19. ^ Nip, Amy (September 6, 2009). "Dumped fish prove to be slippery customers during pond clearance". South China Morning Post.
  20. ^ "Friends catch 1.5m 'monster' fish from Pasir Ris canal after long struggle". The Straits Times. January 21, 2011. 

External links[edit]

Video[edit]