Garpike

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Garpike

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Garpike (gar) are bony fish classified in the family Lepisosteidae, but are distinct from garfish that belong to the family Belonidae. Garpike were once abundant and widely distributed, but are now rare. Some species are found in Mexico, Central America, and the West Indies, and in eastern North America. Garpike are found in shallow waters with dense weeds.

Garpike have a gas bladder, which is well supplied with blood and oxygen. At intervals, garpike rise to the surface to dispel waste air from the bladder and to refill its contents with fresh air. This helps garpike survive in polluted anoxic water that would be intolerable for other fish. Garpike actually drown if caught in a net and denied access to the surface. Their ability to breathe air may have been a factor in their survival to modern times.

Garpike spend their time either near the bottom or rising to the surface, but can develop considerable speed for a short period to obtain food. Garpike are shaped like a cigar, have a long jaw equipped with

KEY TERMS

Ganoid scales Thick scale composed of rhomboid bony plates covered with an enamel-like substance called ganoin, which is characteristically found in some primitive fishes. Its hard surface provides an excellent protective mechanism.

Gas bladder A pouch connected to the throat provided with a blood supply. It helps the fish obtain a better supply of oxygen.

Lateral line A row of pores on the side of the tail and trunk, enabling the fish to detect low-intensity vibrations, movement, and possibly pressure changes.

many sharp teeth, a long, flat snout, and ganoid scales, which fit together to form a hard armor or shell, making them difficult to catch. The scale surface is covered with ganoin, a substance that could be polished to a high luster, and is hard enough to protect against a fish spear. The scales of large gars were used by native Americans for arrowheads, and in pre-Columbian cultures, the shells were used for breastplates. Early farmers would at times use gar hides to cover wooden plowshares to make a hard surface.

The longnose gar (Lepisosteus osseus ) is cylindrically shaped and covered with small ganoid scales arranged in regular rows over its body. Its long and slender jaws are equipped with sharp teeth. It is found over a wide expanse of territory eastward from Montana, the Great Lakes to the St. Lawrence River, to Florida, Alabama, Texas, Mexico, and the Mississippi River drainage system. In the southern part of its range, the longnose gar prefers quiet waters with heavy vegetation, while further north they are found in calm lakes and streams.

Spawning takes place in the spring in shallow waters. Females bulging with eggs are accompanied by several males waiting to fertilize them as they are laid. More than 35,000 eggs may be laid by a 3-ft-long (1 m) female.

The diet of the longnose gar consists mainly of live and dead fish. Gliding near their prey they capture it with a sudden movement. At other times the fish will lie motionless near the surface and suddenly seize an unwary fish swimming by.

The shortnose gar (L. platostomus ) resembles the longnose but has shorter jaws, and a short broad snout. It is the smallest of the gars, rarely more than 2.5 ft (76 cm) long, and is found in the Mississippi River drainage basin.

The largest of the gars in North America is the alligator gar (L. spatula ) found in the streams entering the Gulf of Mexico. This species may reach a length of 10 ft (3 m) and 300 lb (136 kg) in weight, and is highly voracious and is considered especially dangerous to human beings.

Garfish have no commercial value. In some areas they are used for human consumption, but not considered a prized sport fish.

Resources

BOOKS

Migdalski, E.C., and G.S. Fichter. The Fresh and Salt Water Fishes of the World. New York: Greenwich House, 1983.

Moyle, Peter B., and Joseph Cech. Fishes: An Introduction to Ichthyology. 4th ed. New York: Prentice Hall, 1999.

Whiteman, Kate. World Encyclopedia of Fish & Shellfish. New York : Lorenz Books, 2000.

OTHER

Biopix. Garpike (Belone Belo ne) <http://www.biopix.com/Species.asp?Language=en-us&Searchtext=Belone%20belone&Category=Fisk> (accessed November 25, 2006).

McDaniel College. Garpike (Lepisosteus Osseus ) <http://www2.mcdaniel.edu/Biology/wlong/garpike1.html=(accessed November 25, 2006).

Nathan Lavenda