Advertisements

Spotted gar, Lepisosteus oculatus (Introduction – distribution – description – biology) – Video

Review: Abdel Rahman El Gamal (Founder of the website and video channel)

Introduction: The spotted Gar (Lepisosteus oculatus) is a primitive freshwater fish of the family Lepisosteidae, native to North America. Its name Lepisosteus which is Greek means “bony scale”. The spotted gars are among the few fish species with ganoid scales. Females on average are known to live longer than the males whereas male’s average lifespan is 8 years old while the average lifespan of females is 10 years with a maximum lifespan for the species is 18 years old.

Distribution and habitats: The spotted Gar is native to North America and found throughout the rivers and streams that feed into Lake Michigan and Lake Erie, the Mississippi River, and rivers along the northern coast of the Gulf of Mexico from lower Apalachicola River in Florida to Nueces River in Texas, USA.

The species prefers and inhabits clear, quiet water with abundant aquatic vegetation. Even though it is a freshwater species, it occasionally enters brackish waters along the Gulf Coast. The species is tolerant to warm water with low dissolved oxygen levels. The degradation of the spotted gar habitats in some locations had negative impact on the species. Such degradation could be reflected in siltation, dredging, filling and in the decrease or disappearance of aquatic vegetation.

Description: The spotted gar Lepisosteus oculatus are notable for being one of the few extant fish species with ganoid scales. These scales are diamond in shape and are shiny and very tough. They are cylindrical and long which can grow up to 90 cm and weigh of about 3.5 kg with an average length of about 75 cm.  They have long, beak mouth with many sharp prominent teeth used to eat their prey of fish and crustaceans. Their upper body is brown to deep olive-green, and yellowish or whitish below. The species is distinguished by the dark spots on the body, head and fins. The spotted gar has a special swim bladder which enables them to gulp air and live in very poorly oxygenated waters.

Feeding habits: The spotted gar is a voracious predator that feeds on various kinds of fishes and crustaceans starting when juveniles feeding on small crustaceans, mosquito larvae and similar organisms before they quickly shift to prey on fish such as sunfish, gizzard shad, topminnow, shrimp and others as the gar matures. The adult spotted gars do not have many natural predators. However, their early life stages such as fingerlings and juveniles could be preyed upon by a number of fish predators, although the eggs of gar are potentially toxic to many species such as the alligator gar.

Reproduction: As soon as temperature rises to the reproduction optimum temperature, the spotted gars spawn in shallow water with low flow and heavy vegetation. As females are larger than males of the same age, a single female could mate and allow more than a male partner at the same time to fertilize her eggs. On the average, a female lays about 12,000 eggs while could reach up to 20,000 adhesive eggs of green color. Eggs which are laid once/year are attached to the leaves of aquatic plants. There is no parental care after the eggs are laid. Depending on water temperature, eggs hatch after 7-14 days into about 2.5 cm long hatchlings which have specialized pads on their upper jaws that allow them to adhere to vegetation. The larvae remain attached to plants until the yolk sac is absorbed and then the pad is no longer there. Growth is rapid in the first year of life reaching a length of about 25 cm after the first year. Males mature in about two to three years while females mature at three to four years.

Advertisements

Permanent link to this article: https://fishconsult.org/?p=9754

%d bloggers like this: