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Lepisosteus platostomusShortnose gar

By Mark Bradburn

Geographic Range

The shortnosed gar is found in Mississippi River basin from south central Ohio, northern Indiana and Wisconsin to Montana and south to Alabama and Louisiana (Page and Burr, 1991). The species is also found in Lake Michigan drainage in Wisconsin. Shortnose gar presumably dispersed into Wisconsin from the Mississippi river via the Wisconsin and Fox rivers (Priegel, 1963). (Page and Burr, 1991; Priegel, 1963)

Habitat

Habitat of the shortnosed gar includes lakes, swamps, and the calm pools and backwaters of creeks and rivers. They are commonly found near vegetation and submerged logs. (Page and Burr, 1991)

  • Aquatic Biomes
  • lakes and ponds
  • rivers and streams

Physical Description

Gar species in North America are easily recognized by their long snouts, sharply toothed jaws, non-overlapping and diamond shaped ganoid scales, and posterior placement of dorsal and anal fins on the body. Specifically, the shortnose gar is characterized by a short (relative to other gars), broad snout. The upper jaw is longer then the rest of the head and contains only one row of teeth. The shortnose gar has olive or brown coloration with white on the ventral side and black spots on median fins. Paired fins usually lack spots (spots found only on individuals living in clear water). Juveniles have fairly broad dark brown stripes along back and side. (Page and Burr, 1991)

  • Average mass
    1430 g
    50.40 oz
    AnAge
  • Range length
    83 (high) cm
    32.68 (high) in

Development

Shortnose gars may be smaller than 9-10 mm long when they hatch. Although capable of swimming, they use an adhesive structure to hang vertically by their snout from objects in the water, and they will commonly attach to surface film. After exhausting the yolk sac, the fry become more active and assume a horizontal attitude. The fry usually remain near area of egg deposition (Echelle and Riggs, 1972).

Reproduction

Gars begin to spawn in early to mid April until the end of May (Eschelle and Burr, 1972). Shortnose gars spawn in shallow water among the grass and aquatic weeds and prefer grassy sloughs as spawning grounds. Their eggs are large, green, and poisonous to warm-blooded vertebrates, including humans (Eddy, 1974).

  • Breeding season
    early to mid April until the end of May

Shortnose gar do not care for their young.

  • Parental Investment
  • no parental involvement

Lifespan/Longevity

Behavior

Gars are commonly observed breaking the surface and gulping air to replace air in the lung, from which they add oxygen to the bloodstream (Cross and Collins, 1995; Pfleiger, 1997).

Communication and Perception

Food Habits

Young of the year gars consume a variety of food items, ranging from tiny crustaceans to different life stages of insects and fish. The diet of young gars suggests that most feeding is surface oriented. Adult and young of the year gars feed more actively at night than during the day (Echelle and Riggs, 1972).

Hunting activity of gars can be described as stalking rather than active pursuit. Gars are typically opportunist, consuming the most available food. Shortnose gar consume more invertebrates than any other species of gar (Vokoun, 2000).

Gars are efficient ambush predators (Moyle and Cech, 1988). With its long jaws, gars lie in ambush and catch fish with a sideways strike (Bone, 1999).

Predation

Due to gars bony composition and tough, interlocking ganiod scales, gars are nearly impervious to any forms of predation. Adult gars have no known predators except humans. (Iowa Dept of Natural Resources, 1987)

Ecosystem Roles

The shortnose gar are predators that can occupy the role of a scavenger, but often competes for food with common gamefishes like the northern pike, walleyes, and bass. However, they often thrive in waters not suitable for game fishes (Eddy, 1974).

Economic Importance for Humans: Negative

Fishermen have an aversion to the shortnose gar because of their competitive predatory habits and lack of value as a sport fish. Often fishermen attempt to capture them for purposes of removal. Fortunately for the shortnose gar, their slender shape and behavior make them difficult to capture in siene nets (Eddy, 1974).

Conservation Status

Since shortnose gar and other gar species compete with popular gamefishes, they are regarded as a nuisance to many sport fishermen. There are some gar fishing enthusiasts, but their popularity as a sport fish is low. Their perceived lack of value has prompted many actions to eliminate them from some aquatic areas. A related species, the alligator gar Atractosteus spatula, is under intense pressure in some parts of the southern United States (Eddy, 1974).

Contributors

William Fink (editor), University of Michigan-Ann Arbor.

Mark Bradburn (author), University of Michigan-Ann Arbor.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

external fertilization

fertilization takes place outside the female's body

fertilization

union of egg and spermatozoan

insectivore

An animal that eats mainly insects or spiders.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

natatorial

specialized for swimming

native range

the area in which the animal is naturally found, the region in which it is endemic.

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

piscivore

an animal that mainly eats fish

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

swamp

a wetland area that may be permanently or intermittently covered in water, often dominated by woody vegetation.

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

zooplankton

animal constituent of plankton; mainly small crustaceans and fish larvae. (Compare to phytoplankton.)

References

Bone, Q., N. Marshall, J. Blaxter. 1999. Biology of Fishes. Cheltenham, UK: Stanley Thornes Ltd..

Cross, F., J. Collins. 1995. Fishes in Kansas. Lawrence, KS: University Press of Kansas.

Echelle, A., C. Riggs. 1972. Aspects of the early life history of gars *Lepisosteus* in Lake Texoma. Transactions of the American Fisheries Society, 101(1): 106-112.

Eddy, S., J. Underhill. 1974. Northern Fishes. Minneapolis, MN: University of Minnesota Press.

Iowa Dept of Natural Resources, 1987. "The Gar Family" (On-line). Accessed 03/02/2006 at http://www.iowadnr.com/fish/iafish/garfamil.html.

Moyle, P., J. Cech. 1988. Fishes: An Introduction to Ichthyology. Engelwood Cliffs, NJ: Prentice Hall.

Page, L., B. Burr. 1991. A Field Guide to Freshwater Fishes of North America North of Mexico. The Peterson Field Guide Series, vol 42. Boston, MA: Houghton Mifflin Company.

Pflieger, W. 1997. The fishes of Missouri. Jefferson City, MO: Missouri Department of Conservation.

Priegel, G. 1963. Dispersal of the Shortnose Gar, *Lepisosteus platostomus*, into the Great Lakes Drainage. Transactions of the American Fisheries Society, 92 (2): 178.

Volkoun, J. 2002. Shortnose gar (*Lepisoteus platostomus*) foraging on periodical cicadas (Magicicada spp.): territorial defense of profitable pool positions. American Midland Naturalist, 143: 261-265.

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