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| Longnose gar | |
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| At theNew England Aquarium | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Clade: | Ginglymodi |
| Order: | Lepisosteiformes |
| Family: | Lepisosteidae |
| Genus: | Lepisosteus |
| Species: | L. osseus |
| Binomial name | |
| Lepisosteus osseus | |
| Synonyms[2][3] | |
list
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Thelongnose gar (Lepisosteus osseus), also known aslongnose garpike orbilly gar, is aray-finned fish in the familyLepisosteidae. The genus may have been present in North America for about 100 million years.[4] References are made to gars being a primitive group of bony fish because they have retained some primitive features, such as aspiral valve intestine, but they are not primitive in the sense of not being fully developed.
They have an olive brown to green, torpedo-shaped body armored withganoid scales, elongated jaws that form a needle-like snout nearly three times the length of its head, and a row of numerous sharp, cone-shaped teeth on each side of the upper jaw.[5][6] They typically inhabit freshwater lakes,brackish water near coastal areas, swamps, and sluggish backwaters of rivers and streams. They can breathe both air and water, which allows them to inhabit aquatic environments that are low in oxygen.
Longnose gar are found along the east coasts of North andCentral America, and range as far west in the US as Kansas, Texas, and southern New Mexico. They are the only species of the family Lepisosteidae found in New Mexico. Their populations are stable and in some areas abundant in the interior portions of their range.[5]
The longnose gar was first described byCarl Linnaeus (1758), who gave it the nameEsox osseus.[7] The generic nameEsox, which is for pike, was later changed toLepisosteus, the genus for slender gars.Lepisosteus osseus (Linnaeus, 1758), the scientific name for longnose gar, originated by combininglepis, which is Greek for scale, andosteos, the Latin word for bony. The latter references the bone-like,rhomboidal-shaped ganoid scales that protect gars against predation.[7]
Gars have been referred to as primitive fish or living fossils because they have retained some morphological characteristics of their earliest ancestors, such as a spiral valve intestine, and a highlyvascularizedswim bladder lung that supplements gill respiration for breathing both air and water.[8][9][10] Referring to gars as primitive fish simply means they have existed for a long time, having evolved over millions of years into a more perfected morphological state, not that the animal is primitive in the sense that it is not fully developed.[11]
Fossils of the genus dating from 100 million years ago (Mya) have been found in Africa, Asia, Europe, North America, and South America. In the US, fossils of the modern species date back to thePleistocene, where they were discovered in the Kingsdown Formation inMeade County, Kansas, and date back to theIrvingtonian (1.8–0.3 Mya).[12] Longnose gar are found in Central America,Cuba, North America, and theIsla de la Juventud.[13]
Longnose gar are frequently found in fresh water in the eastern half of the US, but some gar were found insalinities up to 31 ppt.[14] Their microhabitats consist of areas near downed trees, stone outcrops, and vegetation.[15]
The most common prey of longnose gar are small fish and occasionallyinsects and smallcrustaceans; they mostly feed at night.[16] In most studies of adultL. osseus, a variety of species made up a majority of the diet, with the dominant prey changing among locations.Inland silversides were particularly common prey of juvenile gar in Lake Texoma, making up 84% of the diet, with gamefishes accounting for less than 1% of the diet.[17][failed verification] In Florida, their diet consisted mainly of fishes, withgizzard shad,bullhead catfish, and smallbluegill particularly common.[18][failed verification] In Missouri, fishes made up 98% of the diet withshiners being the most common prey.[19][failed verification] In some lakes, adult longnose gar may consume large numbers ofsunfish.Menhaden are a major food source along coasts whereL. osseus moves towards the mouths of bayous into higher-salinity waters in the afternoon and evening to find this more prevalent prey. Longnose gar then move back up the bayous, into the lower-salinity waters in the morning.[20][failed verification] Their main competitors are other garfishes, and somewhat commonly, large gar to feed on smaller ones.[21] Historically, Native Americans and early colonists harvested longnose gar as a main food source.[22] Over time, longnose gars have gained in popularity as a sportfish rather than as a food source, but some people consider gar meat a delicacy.[citation needed] Adult longnose gar are consideredapex predators in their aquatic habit, and have few predators, which include humans and in the southern reaches of their range theAmerican alligator.[5] They are most vulnerable to predation when they are young, and are preyed upon by other garfishes, larger fishes, birds of prey, snapping turtles, and water snakes.[23]
Longnose gar have a typical lifespan of 15–20 years with a maximum reported age of 39. This long lifespan allows the female to sexually mature around 6 years old. Males mature sexually as early as 2 years of age. Longnose gar are sexually dimorphic; the females are larger than the males in body length, weight, and fin length. They generally have a clutch size close to 30,000, depending on the weight-to-length ratio of the females; larger females bear larger clutch sizes. They spawn in temperatures close to 20 °C (68 °F) in late April to early July.[24] Eggs have a toxic, adhesive coating to help them stick to substrates, and they are deposited onto stones in shallow water, rocky shelves, vegetation, orsmallmouth bass nests.[25] Their hatch time is 7–9 days; young gar stay in vegetation during the first summer of life.[16] Longnose gar reach a typical length of 28–48 inches (71–122 cm), with a maximum length around 6 feet (1.8 m) and 55 lb (25 kg) in weight.
Currently,[when?] no management of this species is being conducted, nor is it federally listed as endangered, although some states have reported it as threatened (South Dakota,Delaware, andPennsylvania).[26] In the early 1900s, longnose gar were considered as destructive predators. Soon after this characterization, gar population reduction methods were established. Their declining populations are due tooverfishing,habitat loss, dams,road construction, pollution, and otherhuman-caused destruction of the aquatic systems. Because of their long lifespans and older sexual maturity age, factors affecting their reproduction are an issue in preserving them.[27] Overfishing is a large issue for this fish, especially when the fish have not reached sexual maturity due to the female not reaching sexual maturity until about 6 years of age.[27]
