Lepisosteus osseus

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Longnose gar
(Picture from Animal Diversity Web [2])

Longnose gar - Lepisosteus osseus


Identification [1,2]

Adults grow to be about 750mm long and 9.3 grams, and are not sexually dimorphic.
Longnose gar have long, narrow snouts that are more than twice as long as the rest of the head. Their powerful beak-like jaws house many strong, sharp, villiform (conical) teeth.
Adults are olive-brown with a white belly.
Juveniles have a narrow brown stripe along their back and a broad dark brown strip along their sides.
Longnose gar have bilateral symmetry. The dorsal and anal fins are located far back on the body, which is encased in a heavy armor of interlocking, rhomboid, ganoid scales.

  • Phylum: Chordata
    • Subphylum: Vertebrata
  • Class: Actinopterygii
  • Order: Semionotiformes
  • Family: Lepisosteus


Geographical Range [2]

Can be found along the eastern seaboard from the Delaware River, N.J. to central Florida and in the upper Midwest in the St. Lawrence River, Quebec and all of the Great Lakes except Superior. It lives throughout the entire Mississippi River basin and can be found as far south as the Rio Grande drainages of Texas and Mexico.


Habitat [1,2]

Live in a wide variety of lowland habitats, but prefer slow-moving waters. They can tolerate high water temperatures in freshwater, saltwater, or marine areas.


Feeding style [2]

The Longnose gar is a fish predator (piscivore).
Feeds on small crustaceans, insects, and fish eggs.


Reproduction [2]

Sexual reproduction; External fertilization; Oviparous.
As many as 15 males may approach the female, and rapid and violent quivering follows as the sperm and eggs are released. Once shed, the sticky eggs adhere to solid objects on the substrate.
Each female produces around 30,000 large, greenish eggs upstream every spring.
Longnose gar can live up to 22 years in the wild.


Ecological Notes

Longnose gar are palatable, but not popular with anglers. They perceive it as a nuisance because it tends to get tangled in their nets.
However, gar serve as hosts to the parasitic young of the yellow sandshell (glochidia), a freshwater mussel. Without gar, this mussel would disappear.


Other Notes [2]

The eggs are toxic to humans and other mammals and birds, and should not be eaten.
Historically, the heavy rhomboid scales of the gar were often used by local Indians for arrow points, ornaments, and other instruments.
Longnose gar have no major predators due to their heavy armor of interlocking, rhomboid, ganoid scales. There have been a few occurrences of longnose gars being attacked by alligators, but research suggests that these may have been opportunistic events.


Personal Information

This organism was observed at the North Carolina Aquarium [1] during our trip to the Outer Banks for our Marine Biology class.
This was a huge aquarium full of fascinating animals! I was intrigued by spiny lobsters and the pet-a-stingray pool, humbled by the sight of sharks prowling the simulated-shipwreck tank, and captivated by the innate cuteness of playing river otters.




Sources
[1] North Carolina Aquarium on Roanoke Island (374 Airport Road, Manteo, NC 27954)
[2] Animal Diversity Web. (2010, April). Longnose gar. Retrieved April 25, 2010 from <http://animaldiversity.ummz.umich.edu/site/accounts/information/Lepisosteus_osseus.html>

Further reading

To learn more about the Longnose gar, check out these journal articles:

  1. This article from Ecology of Freshwater Fish looks at associations between hydrological connectivity and resource partitioning among sympatric gar species. They found that prey species only overlap when floods occur that connect the oxbow areas of rivers where the gar live, allowing them to move to different areas of the river.
    Link: http://journals.ohiolink.edu/ejc/article.cgi?issn=09066691&issue=v17i0001&article=119_abhcaratraao&search_term=%28longnose+gar%29
    Robertson, C. R., Zeug, S. C., & Winemiller, . K. O. (2008). Associations between hydrological connectivity and resource partitioning among sympatric gar species (Lepisosteidae) in a Texas river and associated oxbows. Ecology of Freshwater Fish, 17(1), 119-129.
    DOI: 10.1111/j.1600-0633.2007.00265.x
  2. This article from Chromosome Research looks at chromosomal characteristics of ribosomal DNA in the Longnose gar. They found that the diploid chromosome count was 56, among other things.
    Link: http://journals.ohiolink.edu/ejc/article.cgi?issn=09673849&issue=v07i0006&article=475_ccordisflglo&search_term=%28longnose+gar%29
    Ráb, P., Rábová, M., Reed, K. M. et al. (1999). Chromosomal Characteristics of Ribosomal DNA in the Primitive Semionotiform Fish, Longnose Gar Lepisosteus osseus. Chromosome Research, 7(6), 475-480.
    ISSN: 239NX





Contributed by Patrick Schnieders - 2010

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