Monday, July 11, 2011

Spotted Alligator Gar

Spotted Gar (Lepisosteus oculatus)


Some people refer to the spotted gar as the spotted alligator gar, but while related, the spotted gar is not a alligator gar. This is most noticeable with the large size disparity between the two.

Description
Gar are lengthy and cylindrical with stretched out mouths. Spotted alligator gar grow to a length of 3 feet, weighing 8 pounds. Their upper body is brown to olive, and they have silver-white sides. Head, body, and fins have olive-brown to black spots that help hide the fish. A wide, dark stripe is on the sides of undeveloped fish. Their long, snout-like mouth is lined with strong, sharp teeth, and their body is sheltered with thick, ganoid (diamond-shaped) scales. Spotted gar may be notable from other Texas gar species by the dark roundish spots on the top of the head, the pectoral fins and on the pelvic fins.
Life History                                          
Gar move leisurely unless trying to catch food, which it grabs in its jaws in a quick sideways charge. They often lie around near the water's surface on warm days. Fry feed mainly on insect larvae and tiny crustaceans, but fish appear on the diet of young gar very early. Prey is usually swallowed headfirst. Spotted gar are eaten by larger fish, alligators, herons, and cottonmouth snakes. 

The long-lived gar has a life span up to 18 years. Males mature in two to three years. Females mature when three to four years old. They produce in shallow water with low flow and heavy vegetation. Several males court a single larger female at the same time. Spawning season is from April to May. The number of eggs varies to a great extent, but up to about 20,000 green, adhesive eggs are attach to aquatic plants. Fry hatch after 10 to 14 days. Young gar have dedicated pads on their upper jaws that allow them to stick to vegetation. They remain attached to plants until they are about 0.75 inches (2cm) long. The pad is lost when last of the yolk sac is absorbed.
 

Gar have a specialized swim bladder which allows them to gulp air and live in the badly oxygenated back waters of Texas' streams, swamps and lakes. Lepisosteus is Greek and means "bony scale", referring to the large ganoid scales. Oculatus means "provided with eyes" in Latin and refers to the dark spots on head, body, and fins. The common name, gar, is rooted in the Anglo-Saxon vocabulary and means "spear." The roe (or egg mass) is highly toxic to humans, animals, and birds.
Habitat
Spotted gar prefer clear, quiet, vegetated waters of streams, swamps and lakes. They from time to time enter brackish waters along the Gulf Coast.
Distribution
Spotted gar are very prevalent, and can be found from central Texas east into western Florida. Their region extends north through the Mississippi River drainage into Illinois, the lower Ohio River, and the Lake Erie drainage.
Other
The spotted gar is one of three gar species local to Texas. They are prehistoric fish and date back to the Cretaceous period, some 65 to 100 million years ago. The ancestors of spotted gar swam with the dinosaurs! A large gar can eat a lot of fish, including catfish, causing them to struggle with some anglers. Because of the opposition and because many people think gar are difficult to clean, gar are sometimes called a "trash" fish. This term may not be defensible when you consider that spotted gar, like all native species, have an imperative role to play in their ecosystem.


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