Lepisosteus osseus is widely distributed throughout the eastern United States. L. osseus can be found along the eastern seaboard from the Delaware River, N.J. to central Florida and in the upper Midwest in the St. Lawrence River, Quebec and all of the Great Lakes except Superior. It lives throughout the entire Mississippi River basin and can be found as far south as the Rio Grande drainages of Texas and Mexico (Page and Burr, 1991).
Biogeographic Regions: nearctic (Native )
The large, greenish eggs of L. osseus are toxic to humans, other mammals and birds and should not be eaten (Netsch and Witt, 1962). Historically, the heavy rhomboid scales of the gar were often used by local Indians for arrow points, ornaments, and other instruments (Suttkus, 1963).
The communication of L. osseus is not well understood. They are a gregarious fish though, often found in groups of two to five, sometimes along with shortnose gar (Lepisosteus platyrhincus) (Holloway, 1954).
Perception Channels: tactile ; chemical
L. osseus is not listed on the IUCN list, the United States Endangered Species Act list or the CITES appendices.
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
L. osseus eggs typically hatch 3-9 days after they have been laid and the larvae are approximately 8-10 mm long at hatching (Yeager and Bryant, 1983; Becker, 1983). The yolk sac is absorbed at approximately 12 mm TL and fins form around 30 mm TL (Simon and Wallus, 1989). Early-stage L. osseus larvae (sac-fry) are relatively inactive and possess an adhesive structure at the tip of the snout by which they attach to objects in the water. By 10 to 11 days after hatching, L. osseus are 18-20 mm long. Young longnose gar grow rapidly and studies have shown that they can gain 3.2 mm and 1.8 grams per day, when maintained in aquaria with an unlimited food supply (Riggs and Moore, 1960). Male longnose gar will typically mature at three to four years of age while females do not mature until six years (Ross, 2001).
L. osseus have historically been perceived as detrimental to game species, such that gar management has emphasized removing the species from aquatic environments (Johnson and Nolte, 1997). In addition, the longnose gar has a propensity for becoming entangled in nets and is considered a pest by commercial fisherman (Ross, 2001). Forbes and Richardson (1920) stated: “it is a wholly worthless and destructive nuisance in relation to mankind. It has, in fact, all the vices and none of the virtues of a predaceous fish” (Netsch and Witt, 1962).
L. osseus, although palatable, are not particularly popular or sought after by anglers. There is a commercial fishery for longnose gar in Arkansas though (Ross, 2001). Consideration has been given to gars as a possible aid in controlling overpopulation of sunfish and yellow perch as well (Niemuth et al., 1959). Additionally, gar skins have been used to a small extent for covering picture frames, purses, and the like. The gar scales are very hard and take on a fine polish (Forbes & Richardson, 1920).
Positive Impacts: pet trade ; food ; controls pest population
The general perception of L. osseus is that it is a nuisance or “trash” fish. However, all species of gar serve as hosts to the parasitic young (glochidia) of the yellow sandshell, a freshwater mussel. Without gar, this mussel would disappear unless it was maintained by artificial means (Becker, 1983).
By 10-11 days after hatching, young gar begin feeding on small crustaceans, such as cladocerans and copepods, and insects, including various dipterans such as chironomids. L. osseus quickly switch to a diet of primarily fish. Gars are active night feeders and much of the feeding is surface-oriented (Becker, 1983). They catch their prey sideways in their well-toothed jaws by lying motionless or slowly stalking prey until the smaller fish are within reach. L. osseus slashes its beak from side to side, impaling the prey on its teeth. The prey is then maneuvered into position to be swallowed headfirst (Branson, 1966).
In most studies of adult L. 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 (Eschelle, 1968). In Florida, the diet was comprised mainly of fishes, with gizzard shad, bullhead catfish, and small bluegill particularly common (Crumpton, 1971). In Missouri, Netsch (1964) found that fishes made up 98% of the diet with shiners being the most common prey. In some lakes, adult longnose gar may consume large numbers of sunfishes. Menhaden are a major food source along coasts where L. osseus move towards the mouth of bayous into higher salinity waters in the afternoon and evening to find this more prevalent prey. Longnose gar will then move back up the bayous, into the lower salinity waters in the morning (Ross, 2001).
Animal Foods: fish; eggs; insects
Primary Diet: carnivore (Piscivore )
L. osseus live in a variety of lowland habitats, preferring sluggish areas of larger rivers, lakes, reservoirs and estuaries. They can live in brackish water and are common in the deeper bayous along the Gulf Coast (Goodyear, 1967). L. osseus can tolerate high water temperatures and can often be found near the water surface on warm days or nights (Becker, 1983).
Habitat Regions: saltwater or marine ; freshwater
Aquatic Biomes: lakes and ponds; rivers and streams; coastal
Other Habitat Features: estuarine ; intertidal or littoral
Longnose gar can be aged by annular marks on their branchiostegal rays. Female L. osseus grow more quickly and live longer than males. They are capable of living well beyond 17 years and some have reached 22 years in the wild. In captivity, female L. osseus have lived up to 30 years (Ross, 2001). Male longnose gar typically do not live longer than 11 years in the wild. A study by Netsch and Witt (1962) in Missouri did not find any males older than 17 years of age.
Range lifespan
Status: wild: 22 (high) years.
Range lifespan
Status: captivity: 30 (high) years.
Typical lifespan
Status: wild: 17 (high) years.
Average lifespan
Status: captivity: 20.0 years.
Average lifespan
Status: captivity: 24.0 years.
Longnose gar have long, narrow snouts more than twice as long as the rest of the head and they have abundant, sharp, villiform teeth. Mature L. osseus are olive brown in color with a white belly. Dark spots can be found on the median fins and, in individuals from clear water, on the body. Young L. osseus have a narrow brown stripe along their back and a broad dark brown strip along their sides (Page and Burr, 1991; Becker, 1983). The dorsal and anal fins of the longnose gar are located far back on the body, which is encased in a heavy armor of interlocking, rhomboid, ganoid scales (Ross, 2001).
Range mass: 5 to 18600 g.
Range length: 8 to 1830 mm.
Average length: 660-838 mm.
Other Physical Features: bilateral symmetry
As previously mentioned, L. osseus are encased in a heavy armor of interlocking, rhomboid, ganoid scales. The ganoid scales are composed of two layers, an outer layer of ganoin and an inner layer of isopedine, both of which are penetrated by blood vessels. As a result of this armor, the longnose gar has no major predators. There have been occurrences of longnose gars being attacked by alligators, but research suggests that these may have been opportunistic events (McCormack, 1967).
Known Predators:
During the mating process as many as 15 males may approach the female. If she is ready, she will lead them in an elliptical pattern for up to 15 minutes prior to spawning. Once over the spawning bed, the males will nudge the female with the ends of their snouts in the pectoral, lateral, and ventro-lateral areas. During this phase, frequent surfacing and gulping take place. Ultimately, the spawning group will position itself at one place with heads down and snouts very close to the bottom. Rapid and violent quivering follows as the sperm and eggs are released (Haase, 1969).
Mating System: polyandrous
Spawning occurs in the spring and summer for L. osseus. In rivers, longnose gar make upstream spawning runs during the spring period of high water, then move downstream into larger pools. They have also been seen spawning in open, wind-exposed areas over rocks as well as gravelly, weedy sites. Spawning takes place in shallow water resulting in the backs of the fish sometimes being exposed. Often, more than one male will attend to the larger female during spawning. She will not release all of her eggs at the same time. Once shed, the eggs become very sticky and adhere to solid objects on the substrate (Ross, 2001). Females produce about 30,000 eggs per year; 77,000 eggs were once recorded in a female observed in Tennessee (Etnier and Starnes, 1993).
Breeding season: Spring/Summer
Range number of offspring: 4,273 to 77,000.
Average number of offspring: 30,000.
Range gestation period: 3 to 9 days.
Range age at sexual or reproductive maturity (female): 3 to 6 years.
Range age at sexual or reproductive maturity (male): 3 to 6 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; sexual ; fertilization (External ); oviparous
L. osseus provide no parental care. Research has shown frequent occurrences of the longnose gar laying eggs in smallmouth bass nests, where the male bass guarding the nest provides protection for the young gar in addition to its own young (Goff, 1984).
Parental Investment: pre-fertilization (Provisioning)
The longnose gar (Lepisosteus osseus), commonly referred to as the needlenose gar, is a species of ray-finned fish believed to have diverged from the rest of the Actinopterygii class long ago. Lepisosteiforme fossils have been found from the late Cretaceous period, about 66 million years ago, when they first evolved from a shared common ancestor with other teleost fish (McGrath, 2010). They have long, slender and usually spotted bodies with a thick armor of diamond shaped scales for protection. Their most distinctive feature, however, is their beak-like mouth from which it gets its name.
On average, gars have a lifespan of 17 years in the wild but can range anywhere between 15 and 20 years of age. Like most other vertebrates, gars are sexually dimorphic with females being the larger sex. Their behaviors displayed from the moment they hatch to their hunting tactics as adults shine a light on their unique life history and continuation as a species today.
HUNTING AND FEEDING
Longnose gars can feed at any time of day but prefer to hunt nocturnally (McCormack, 1969). They have been known to ambush their prey instead of chasing it down, a method that works best when diurnal species of fish are quiescent (McCormack, 1969). Gars have special adaptations such as a lateral line system that may help them sense prey in turbid waters and low light. The small hairs that make up this lateral line are able to detect vibrations and slight movements, guiding the predator in the direction of its prey.
After a potential prey has been detected, the gar will wait quietly near the surface of the water, keeping any movements to a minimum. To other fishes, the immobile gar looks like dead vegetation or a piece of wood. Although they do swim towards their prey, chasing after them introduces the problem of pushing the food item away in the predator’s attempt to swim forward. Suction feeding is a common solution, but not feasible due to the mouth morphology of the gars. Instead, gars will inconspicuously swim towards their prey sideways and attack from that angle. Swimming sideways allows the gar to move forward without creating much drag or resistance in the water. Additionally, this technique will prevent the prey from being pushed forward, minimizing both the predator’s time and effort in hunting. After attacking, the gar, using its jaw, will then turn its prey item so that it can be swallowed headfirst (McCormack, 1969).
In a study of the stomach content of longnose gars in Lake Texoma, a lake located on the shared border between Texas and Oklahoma, the ratio of fish to insects (including terrestrial invertebrates that are attracted to aquatic vegetation within gar territory) was approximately 9:1 (Echelle, 1968). This disparity can be explained in part by the gars’ previously mentioned preferred method of hunting as they transition from juveniles into adults with larger caloric requirements.
Schools of fish that stay near the surface of the water to feed are susceptible to predation in general but gars will most often hunt solitary or stray individuals (Echelle, 1968). Particular delicacies for adult gars include herrings, shads, and perches. Increased nocturnal swimming and foraging activity is also something observed most frequently in adult gars. The diurnal hunting of juveniles differs slightly from that of adults. Although they use many of the same techniques. Younger gars are less likely to feed at the water’s surface due to their tendency to hunt during the day when other fish are more alert. Juveniles begin to feed on small crustaceans and insect larvae at a young age. By the time they reach maturity (between 6-7 years after hatching for females and 2-3 years for males) they will have developed full-sized elongated mouths with sharp teeth adapted to piscivory (Echelle, 1968).
Different species of gars studied in the Brazos River, Texas showed preferences for different food types. While spotted gars (Lepisosteus oculatus) tend to consume the most abundant fish in its habitat, longnose gars in the river channels selected against smaller fish such as minnows almost entirely. Despite the smaller prey being available at all times, longnose gars tended to avoid them whenever possible to decrease they energy expenditure during hunting and instead went after fish that would provide a larger benefit given the costs (Robertson et al, 2007). This particular behavior of food selectivity is in accordance with the optimal foraging theory (OFT) model, which states that although an animal will obtain energy by consuming the prey it has hunted, the act of hunting itself requires time and energy that must be taken into account by the predator. Thus, a predator will choose prey that results in a net-positive return on energy (Pyke, 1984). Ultimately, the individual’s behavior while foraging will determine its survival and fitness.
BREATHING
Fluctuating environmental and habitat conditions can have an impact on gar behavior. For example, in poorly oxygenated waters, the gars’ highly vascularized swim bladder allows it to survive by breathing in atmospheric air (Icardo et al, 2015). Gars are able to control their buoyancy in water by inflating or deflating their swim bladder. The apical surface of their bladder is lined with mucociliated epithelium. The inside is covered by a respiratory epithelium that produces surfactant to keep the area of diffusion moist while capillary walls run along the respiratory surface to aid in gas exchange (Icardo et al, 2015). Although gars can use both structures (gills and the swim bladder) to breathe, in regions of low oxygen levels, they are able to cover their gills and use only the swim bladder to obtain all their oxygen (Icardo et al, 2015). Additionally, gars will often surface to exhale and inhale before returning underwater for longer periods of time (McCormack, 1969).
SPAWNING PREPARATION AND COURTSHIP
To reproduce, longnose gars travel away from their usual slow moving streams, rivers, and brackish waters in search of favorable environmental conditions (i.e. warm temperatures and high stream flow) for their eggs to thrive in. They migrate to smaller freshwater streams to spawn in fast moving streams with shallow riffles (Johnson and Noltie, 1996). Observations of their mating behaviors by Johnson and Noltie (1996) began as early as April and lasted until late May. Occurrences of matings were the most frequent when water levels and stream flow were high, however, these behaviors were less likely to be observed in colder temperatures. Some of these migrations to shallower, warmer waters may be “triggered” by a temperature minimum in their current location (Johnson and Noltie, 1996).
The mating rituals that gars partake in can involve various males all with the common goal of pursuing a single female. She will lead them to the spawning beds located in shallow water where the courting process can begin. The group of males swims around in an elliptical pattern for some time before one of the males nudges the female on her pectoral or lateral side to signal mating. The male’s total length, weight, and anal fin height all play a role in the female’s mate choice (McGrath, 2010).
Nests are not prepared by either sex and eggs are only deposited in convenient locations within the spawning beds themselves. The female will deposit her eggs in batches in different areas of the bed but the dominant male of the group will quickly fertilize them all at once and chase off the subordinates (Johnson and Noltie, 1996). Parental care is absent; however, there is an alternative method used by both sexes, involving brood parasitism, to increase the likelihood of offspring survival.
BROOD PARASITISM
A study of eggs from the nests of smallmouth bass (Micropterus dolomieu) revealed foreign eggs and larvae from an unknown species (Goff, 1984). These eggs were hatched at an aquaria and revealed to be longnose gars (Goff, 1984). In experiments, the longnose gar eggs were significantly larger than those of the bass, yet regardless of the size, appearance, or olfactory cues they released, the male smallmouth bass would protect everything in his nest, including the brood-parasitic gar eggs. Interspecific brood care is especially beneficial for the gars because adults do not particularly provide any sort of parental care following the process of fertilization.
While male bass are extremely territorial of their nests during the day, they become more quiescent at night. Adult gars take advantage of this opportunity to parasitize bass nests during this time. Male gars will court females like normal but instead of shedding her eggs for the male to fertilize in spawning beds, she will use the bass nests. The male bass will vigilantly guard the eggs, chasing off predators that he is able to take on but only while he is awake and alert. The disparity in size of the eggs in the bass nest will also often attract a great deal more predators (Goff, 1984). Other piscivores that would normally ignore the smaller eggs of the smallmouth bass are now more attracted to the nest. Gar eggs are toxic to humans but other aquatic species, they are the perfect prey item. For the bass, this means a greater chance of survival for their own young as gar eggs are usually the first if not the only ones to be eaten by predators (Goff, 1984).
Gars are primarily freshwater fish found only in North America. There are seven known species of gar, four species of which are within the genus Lepisosteus (Herrington et al., 2008). The other three species are in the genus are the spotted gar (L. oculatus), shortnose gar (L. platostomus) and the Florida gar (L. platyrhincus). Gars all have long slender bodies, beak-like jaws, and large, thick, diamond shaped scales. The longnose gar is easily distinguishable from other gar species by its extremely long and narrow snout (Kentucky Department of Fish & Wildlife, Gandy et al., 2012). Aside from snout length, a single row of sharp villiform teeth in the upper jaw distinguishes this species from the others (Gandy et al., 2012). Longnose gar bodies, like other gar species, are covered with rhomboidal ganoid scales. The outer layer of these scales is made of ganoin, a shiny substance that resembles enamel, and the inner layer is made of isopedine, which is composed of connective tissue embedded with bone, both penetrated by blood vessels.
Juvenile longnose gars have a pronounced broad, dark mid-lateral stripe that runs from the snout to the base of the caudal fin with a distinct white stripe directly below it, which is lost in adults. The typical coloration of adult longnose gar is olivaceous brown dorsally and laterally, fading into a pale yellow or white ventrally (Gandy et al., 2012). The longnose gar also has spots on its dorsal, anal, and caudal fins (Goddard 2010).
Sexual size dimorphism is the easiest way to tell males and females apart. Females are significantly larger than males before the spawning season. Most females then undergo weight loss during spawning, although it is not a significant weight loss. This weight loss is from the eggs they release (Johnson and Noltie, 1997). Males also tend to have larger mid-snout width, head width and anal-fin base length (McGrath and Hilton, 2012).
Although most wild-caught longnose gars fit the normal coloration patterns and can be identified using the diagnostic characteristics listed above, there are some exceptions. A study in 2008 recorded the first known lab-reared gar hybrids between a female longnose gar and a male alligator gar. These hybrids’ body coloration and transverse scale rows were similar to those of a longnose gar; snout length and shape fell between those of the longnose and alligator gars; and the hybrids had two rows of teeth on the upper jaw like alligator gars. Although no research has been done on wild longnose gar/ alligator gar hybrids, there are many claims by fishermen catching such individuals in some rivers of the southeastern United States (Herrington et al., 2008). Although there are other gar species that are more closely related to the longnose gar, there are not current studies documenting hybridization between those species and the longnose gar.
Melanistic deviations from the normal pattern have been found in individuals from river systems that drain into the Atlantic Ocean. These individuals range from entirely black with the typical pattern completely unidentifiable, to individuals with dark olivaceous, brown backs and black sides and venter. The cause of melanism is not a response to environmental factors, but rather genetically controlled (Woolcott and Kirk, 1975). Although Woolcott and Kirk’s findings support this claim because both melanistic and normally pigmented fish were taken from the same areas, others believe coloration varies in relation to water clarity, with individuals having a deeper green coloration and stronger brown hues in murky waters (Gandy et al., 2012).
In the Actinopterygii (ray-finned fish), morphological and molecular evidence support a subclass called the Neopterygii, which is composed of three extant clades: teleosts, amiids, and lepisosteids (Nelson 2006; Hurley et al. 2007). The longnose gar is classified as a lepisosteid in the Order Semionotiformes (Nelson 2006; Hurley et al. 2007). The amiids, or bowfins, are in Order Amiiformes with only one surviving species, Amia calva (Nelson 2006; Hurley et al. 2007). The teleosts (Order Teleosti) are the major lineage of ray-finned fish, having at least 23,453 species (Volff 2005).
Since they are descendants of the ancestral ray-finned fish, gars and bowfins share some common ancestor with teleosts (Groff and Youson 1997). Using morphological evidence, Geoff and Youson (1997) and Nelson (2006) concluded that gars diverged into a separate lineage before amiids and teleosts, indicating that amiids and teleosts are sister taxa, that in turn share a most-recent common ancestor with the gars. However, this phylogenetic relationship has been challenged by molecular data, which strongly support a gars/amiids sister taxa relationship, the Holostei, and the relationships have been debated since (Hurley et al. 2007).
Grande (2010) compared skeletal structures of all living and fossil gars, specifically focusing on the longnose and alligator gar as the type species for their respective genera, to attempt to resolve this evolutionary controversy. During this research, Grande (2010) recognized nine new fossil Lepisosteus, a new fossilized Lepisoteidae genus called Cuneatus, and a new fossilized family of gars, Obaichthyidae, that contains four species divided into two genera, Obaichthys and Dentilepisosteus. This research helped to support the hypothesis that bowfins and gars are indeed sister taxa based on shared skeletal similarities, including the loss of the pterotic bone in the ear and the presence of a supra angular bone in the jaw, paired vomer (facial bone), and large nasal process.
Developmental studies may also shed light on early branches of the Actinopterygian tree. Teleosts, bowfins, and gars all have spermatozoa without an anterior cap-like structure called an acrosome, suggesting that this is an ancestral character (Jaroszewska and Dabrowski 2009). In contrast, Jaroszewska and Dabrowski (2009) reviewed gar embryology studies from the nineteenth century, finding that gar development was different from bowfin and teleost development. This developmental difference suggested that bowfins and teleosts were sister taxa. Specifically, gar development differed because gars form a distinct layer of yolk called a periblast, and have surface cells that fold into the interior of the gastrula. Gars also go through mesoblastic or partial cleavage (Long and Ballard 2001). The similarities among their developmental characteristics supports that gars, bowfins, and teleosts are all part of the Neopterygii subclass.
To describe the evolutionary relationships among the gar species (i.e., Order Semionotiformes), several studies used molecular phylogenetics. Wright et al. (2012) used one mitochondrial gene and seven nuclear genes sequenced among the gars. Sipiorski (2011) used four mitochondrial loci and one nuclear locus for comparison. For his phylogenetic analysis, Cavin (2010) used 43 characters, including presence or absence of the basisphenoid (bone in base of cranium), interopercle (membrane bone between other gill bones), and opisthotic (bone in the ear).
Both Cavin (2010) and Sipiorski (2011) estimated that the last common ancestor of bowfins and gars lived 244 million years ago in the Middle Triassic Period, while Lepisosteidae diverged from other gar families 100 million years ago in the Cretaceous Period. The genus Lepisosteus diverged 50 million years ago in the Tertiary Period. Unlike Grande (2010) who placed the longnose gar as sister taxon to the spotted and Florida gar, with those three gars were sister to the shortnose gar, both Wright et al. (2012) and Sipiorski (2011) found that the longnose gar shared a more recent common ancestor with the shortnose gar, relative to the other gars in the study. Sipiorski (2011) estimated that shortnose and longnose gar diverged about 28 million years ago, while the spotted and Florida gar diverged approximately 23 million years ago, making them sister taxa to the shortnose and longnose gar.
Oguri (1987) examined the interrenal cells of longnose gar for comparison with cartilaginous and holostean fishes. In the gar, many scattered cells form the interrenal gland of the longnose gar on top of their kidney. Oguri (1987) discovered that the interrenal cells of longnose gar had numerous fat droplets. Although their specific function in longnose gar is unknown, the fat droplets most likely store and synthesize cholesterol (Jeon 2003). Such fat droplets are found in the cartilaginous fish (sharks: Chondrichthyes), but not in teleosts, suggesting that loss of fat droplets is a derived trait.
As a family, gars can breathe air, have a shortened heterocercal tail for more effective swimming, have ganoid scales, which are shaped like diamonds and coated with hard ganoin, and have some parts of a spiral valve in their small intestine that allows for increased nutrient absorption (McGrath 2010). Both bowfins and gars have a respiratory gas bladder that evolved to not only control their position in the water but also breathe in oxygen from the air (Graham 1997). Their respiratory gas bladder is similar to a flattened bag with a dorsal aorta located on top of it to provide adequate blood circulation (Lukáš 1989). Inside the gas bladder, smaller compartments and alveoli are created by many connecting septa composed of flat epithelial cells layered on top of muscle fibers for gas exchange. These characters help to further support gars as the sister taxa of bowfins.
The roe (external eggs) of the longnose (Lepisosteus osseus), spotted (Lepisosteus oculatus), and alligator (Atractosteus spatula) gars contain ichthyootoxin, a toxin known to be poisonous to at least laboratory mice, humans, and domesticated mammals (Colby 1943; Netsch and Witt 1962; Fuhrman et al. 1969). Of course, none of these vertebrates are natural predators of gar eggs, so they cannot speak to whether the toxin evolved as a predator defense. In contrast, several studies have been conducted to test the toxicity of ichthyootoxin on the natural predators of gar roe, including crayfish, sunfish, and catfish (Burns et al. 1981; Ostrand et al. 1996). Based on an experiment conducted by Burns et al. (1981), regardless of whether they were fed or injected with alligator gar roe extract, all crayfish (sex and species unknown due to immaturity) died within one day; more crayfish died from longnose gar roe than spotted gar roe within two days, suggesting that longnose gar roe had intermediate toxicity relative to alligator and spotted gar roe. Regardless of which gar’s toxin was used and crayfish mortality, after injection, all the crayfish experienced short-term changes in behavior, including overall joint stiffness in walking, restlessness, twitching of back legs, and loss of coordination in movement (Burns et al. 1981). Crayfish are likely predators on longnose gar roe because there are often many young crayfish in the places where longnose gar spawn, so the toxin may act to protect roe against these predators and increase the fitness of the parents whose roe are toxic (Burns et al. 1981). Thus, toxic eggs are probably adaptive. In addition, roe toxicity may be an adaptation to crayfish because longnose gar have more visibly colored eggs and spawn in sparsely vegetated locations, decreasing the longnose gar roe’s crypticity and increasing its predator vulnerability (Burns et al. 1981). Since fish are also visual predators, experiments that use longnose gar roe instead of alligator gar roe are needed to test whether predatory fish are affected by longnose gar ichthyootoxin. Further research to examine the potential evolutionary relationship between roe color and ichthyootoxin has not been conducted, so whether longnose gar roe color is an aposematic signal or not is currently unknown.
Although crayfish mortality was high in those crayfish that ate gar roe, alligator gar roe did not cause any bluegill sunfish deaths (Burns et al. 1981). Alligator gar roe was the most toxic of the three gar species tested, according to the crayfish survey; thus, it is unlikely that the less toxic longnose gar roe causes mortality in bluegill sunfish, though this was not tested directly, and vertebrate reactions to toxins are likely to differ from that of invertebrates. However, assuming that longnose gar roe does not cause any negative side effects or death of predatory fish, the data suggest that ichthyootoxic gar roe likely evolved as an adaptation to crayfish predation and that fish predation on gar eggs is a weaker selective force.
Consistent with this generalization, Netsch and Witt (1962) found that the roe of a different gar (shortnose gar) did not cause mortality in bluegill sunfish (Lepomis macrochirus) or another predatory fish (northern river carpsucker; Carpiodes carpio). Similarly, Ostrand et al. (1996) fed spotted gar roe to green sunfish (Lepomis cyanellus) and channel catfish (Ictalurus punctatus), and both predatory fish survived, so it seemed that the spotted gar roe toxin had no effect on the predatory fish. Both predatory fish had no measured weight loss, and some even gained weight, indicating that spotted gar roe may be part of their natural prey (Ostrand et al. 1996). Therefore, Ostrand et al. (1996) concluded that spotted gar toxin was unlikely to be used as a method of defense against fish and that the toxin might have been the result of a mutation in another chemical compound that had widespread (pleiotropic) effects, being toxic to crayfish, thereby, through chance. However, since the experiments did not test longnose gar roe, which had potentially greater toxicity than the spotted gar roe, further studies are needed to clarify whether longnose gar roe ichthyootoxin is adaptive for specific or general predator protection, exists for some other function, or is the result of drift and contingency. The location of the longnose gar in its phylogeny allows further speculation of the role of ichthyootoxin.
Within the Class Osteichthyes, or the bony fish, longnose gars are an early branch of Actinopterygii, or ray-finned fish (Alfaro et al. 2008). Longnose gars (L. osseous) are a member of the genus Lepisosteus along with three other species, including the shortnose gar (L. platostomus), spotted gar (L. oculatus), and Florida gar (L. platyrhincus) (Alfaro et al. 2008). Besides the genus Lepisosteus, the gar family, Lepisosteidae, includes the genus Atractosteus, which is composed of the alligator gar (A. spatula), Cuban gar (A. tristoechus), and tropical gar (A. tropicus) (Alfaro et al. 2008). Since longnose gar are in the same genus as the shortnose and spotted gar and the same family as alligator gar, and none of the species caused any negative effects on fish predators, it is likely that ichthyootoxin is an evolutionarily shared trait at least at the family level. If ichthyootoxin is an evolutionarily shared trait, then it cannot be considered a derived trait that only longnose gar have and supports that it is not a functional adaptation in longnose gar. However, since longnose gar roe has not been experimentally fed to predatory fish, if future experiments conducted on longnose gar roe show that they cause predatory fish mortality, it would suggest that ichthyootoxin evolved further in longnose gar to protect their roe from predatory fish.
The roe (external eggs) of the longnose (Lepisosteus osseus), spotted (Lepisosteus oculatus), and alligator (Atractosteus spatula) gars contain ichthyootoxin, a toxin known to be poisonous to at least laboratory mice, humans, and domesticated mammals (Colby 1943; Netsch and Witt 1962; Fuhrman et al. 1969). Of course, none of these vertebrates are natural predators of gar eggs, so they cannot speak to whether the toxin evolved as a predator defense. In contrast, several studies have been conducted to test the toxicity of ichthyootoxin on the natural predators of gar roe, including crayfish, sunfish, and catfish (Burns et al. 1981; Ostrand et al. 1996). Based on an experiment conducted by Burns et al. (1981), regardless of whether they were fed or injected with alligator gar roe extract, all crayfish (sex and species unknown due to immaturity) died within one day; more crayfish died from longnose gar roe than spotted gar roe within two days, suggesting that longnose gar roe had intermediate toxicity relative to alligator and spotted gar roe. Regardless of which gar’s toxin was used and crayfish mortality, after injection, all the crayfish experienced short-term changes in behavior, including overall joint stiffness in walking, restlessness, twitching of back legs, and loss of coordination in movement (Burns et al. 1981). Crayfish are likely predators on longnose gar roe because there are often many young crayfish in the places where longnose gar spawn, so the toxin may act to protect roe against these predators and increase the fitness of the parents whose roe are toxic (Burns et al. 1981). Thus, toxic eggs are probably adaptive. In addition, roe toxicity may be an adaptation to crayfish because longnose gar have more visibly colored eggs and spawn in sparsely vegetated locations, decreasing the longnose gar roe’s crypticity and increasing its predator vulnerability (Burns et al. 1981). Since fish are also visual predators, experiments that use longnose gar roe instead of alligator gar roe are needed to test whether predatory fish are affected by longnose gar ichthyootoxin. Further research to examine the potential evolutionary relationship between roe color and ichthyootoxin has not been conducted, so whether longnose gar roe color is an aposematic signal or not is currently unknown.
Although crayfish mortality was high in those crayfish that ate gar roe, alligator gar roe did not cause any bluegill sunfish deaths (Burns et al. 1981). Alligator gar roe was the most toxic of the three gar species tested, according to the crayfish survey; thus, it is unlikely that the less toxic longnose gar roe causes mortality in bluegill sunfish, though this was not tested directly, and vertebrate reactions to toxins are likely to differ from that of invertebrates. However, assuming that longnose gar roe does not cause any negative side effects or death of predatory fish, the data suggest that ichthyootoxic gar roe likely evolved as an adaptation to crayfish predation and that fish predation on gar eggs is a weaker selective force.
Consistent with this generalization, Netsch and Witt (1962) found that the roe of a different gar (shortnose gar) did not cause mortality in bluegill sunfish (Lepomis macrochirus) or another predatory fish (northern river carpsucker; Carpiodes carpio). Similarly, Ostrand et al. (1996) fed spotted gar roe to green sunfish (Lepomis cyanellus) and channel catfish (Ictalurus punctatus), and both predatory fish survived, so it seemed that the spotted gar roe toxin had no effect on the predatory fish. Both predatory fish had no measured weight loss, and some even gained weight, indicating that spotted gar roe may be part of their natural prey (Ostrand et al. 1996). Therefore, Ostrand et al. (1996) concluded that spotted gar toxin was unlikely to be used as a method of defense against fish and that the toxin might have been the result of a mutation in another chemical compound that had widespread (pleiotropic) effects, being toxic to crayfish, thereby, through chance. However, since the experiments did not test longnose gar roe, which had potentially greater toxicity than the spotted gar roe, further studies are needed to clarify whether longnose gar roe ichthyootoxin is adaptive for specific or general predator protection, exists for some other function, or is the result of drift and contingency. The location of the longnose gar in its phylogeny allows further speculation of the role of ichthyootoxin.
Within the Class Osteichthyes, or the bony fish, longnose gars are an early branch of Actinopterygii, or ray-finned fish (Alfaro et al. 2008). Longnose gars (L. osseous) are a member of the genus Lepisosteus along with three other species, including the shortnose gar (L. platostomus), spotted gar (L. oculatus), and Florida gar (L. platyrhincus) (Alfaro et al. 2008). Besides the genus Lepisosteus, the gar family, Lepisosteidae, includes the genus Atractosteus, which is composed of the alligator gar (A. spatula), Cuban gar (A. tristoechus), and tropical gar (A. tropicus) (Alfaro et al. 2008). Since longnose gar are in the same genus as the shortnose and spotted gar and the same family as alligator gar, and none of the species caused any negative effects on fish predators, it is likely that ichthyootoxin is an evolutionarily shared trait at least at the family level. If ichthyootoxin is an evolutionarily shared trait, then it cannot be considered a derived trait that only longnose gar have and supports that it is not a functional adaptation in longnose gar. However, since longnose gar roe has not been experimentally fed to predatory fish, if future experiments conducted on longnose gar roe show that they cause predatory fish mortality, it would suggest that ichthyootoxin evolved further in longnose gar to protect their roe from predatory fish.
The roe (external eggs) of the longnose (Lepisosteus osseus), spotted (Lepisosteus oculatus), and alligator (Atractosteus spatula) gars contain ichthyootoxin, a toxin known to be poisonous to at least laboratory mice, humans, and domesticated mammals (Colby 1943; Netsch and Witt 1962; Fuhrman et al. 1969). Of course, none of these vertebrates are natural predators of gar eggs, so they cannot speak to whether the toxin evolved as a predator defense. In contrast, several studies have been conducted to test the toxicity of ichthyootoxin on the natural predators of gar roe, including crayfish, sunfish, and catfish (Burns et al. 1981; Ostrand et al. 1996). Based on an experiment conducted by Burns et al. (1981), regardless of whether they were fed or injected with alligator gar roe extract, all crayfish (sex and species unknown due to immaturity) died within one day; more crayfish died from longnose gar roe than spotted gar roe within two days, suggesting that longnose gar roe had intermediate toxicity relative to alligator and spotted gar roe. Regardless of which gar’s toxin was used and crayfish mortality, after injection, all the crayfish experienced short-term changes in behavior, including overall joint stiffness in walking, restlessness, twitching of back legs, and loss of coordination in movement (Burns et al. 1981). Crayfish are likely predators on longnose gar roe because there are often many young crayfish in the places where longnose gar spawn, so the toxin may act to protect roe against these predators and increase the fitness of the parents whose roe are toxic (Burns et al. 1981). Thus, toxic eggs are probably adaptive. In addition, roe toxicity may be an adaptation to crayfish because longnose gar have more visibly colored eggs and spawn in sparsely vegetated locations, decreasing the longnose gar roe’s crypticity and increasing its predator vulnerability (Burns et al. 1981). Since fish are also visual predators, experiments that use longnose gar roe instead of alligator gar roe are needed to test whether predatory fish are affected by longnose gar ichthyootoxin. Further research to examine the potential evolutionary relationship between roe color and ichthyootoxin has not been conducted, so whether longnose gar roe color is an aposematic signal or not is currently unknown.
Although crayfish mortality was high in those crayfish that ate gar roe, alligator gar roe did not cause any bluegill sunfish deaths (Burns et al. 1981). Alligator gar roe was the most toxic of the three gar species tested, according to the crayfish survey; thus, it is unlikely that the less toxic longnose gar roe causes mortality in bluegill sunfish, though this was not tested directly, and vertebrate reactions to toxins are likely to differ from that of invertebrates. However, assuming that longnose gar roe does not cause any negative side effects or death of predatory fish, the data suggest that ichthyootoxic gar roe likely evolved as an adaptation to crayfish predation and that fish predation on gar eggs is a weaker selective force.
Consistent with this generalization, Netsch and Witt (1962) found that the roe of a different gar (shortnose gar) did not cause mortality in bluegill sunfish (Lepomis macrochirus) or another predatory fish (northern river carpsucker; Carpiodes carpio). Similarly, Ostrand et al. (1996) fed spotted gar roe to green sunfish (Lepomis cyanellus) and channel catfish (Ictalurus punctatus), and both predatory fish survived, so it seemed that the spotted gar roe toxin had no effect on the predatory fish. Both predatory fish had no measured weight loss, and some even gained weight, indicating that spotted gar roe may be part of their natural prey (Ostrand et al. 1996). Therefore, Ostrand et al. (1996) concluded that spotted gar toxin was unlikely to be used as a method of defense against fish and that the toxin might have been the result of a mutation in another chemical compound that had widespread (pleiotropic) effects, being toxic to crayfish, thereby, through chance. However, since the experiments did not test longnose gar roe, which had potentially greater toxicity than the spotted gar roe, further studies are needed to clarify whether longnose gar roe ichthyootoxin is adaptive for specific or general predator protection, exists for some other function, or is the result of drift and contingency. The location of the longnose gar in its phylogeny allows further speculation of the role of ichthyootoxin.
Within the Class Osteichthyes, or the bony fish, longnose gars are an early branch of Actinopterygii, or ray-finned fish (Alfaro et al. 2008). Longnose gars (L. osseous) are a member of the genus Lepisosteus along with three other species, including the shortnose gar (L. platostomus), spotted gar (L. oculatus), and Florida gar (L. platyrhincus) (Alfaro et al. 2008). Besides the genus Lepisosteus, the gar family, Lepisosteidae, includes the genus Atractosteus, which is composed of the alligator gar (A. spatula), Cuban gar (A. tristoechus), and tropical gar (A. tropicus) (Alfaro et al. 2008). Since longnose gar are in the same genus as the shortnose and spotted gar and the same family as alligator gar, and none of the species caused any negative effects on fish predators, it is likely that ichthyootoxin is an evolutionarily shared trait at least at the family level. If ichthyootoxin is an evolutionarily shared trait, then it cannot be considered a derived trait that only longnose gar have and supports that it is not a functional adaptation in longnose gar. However, since longnose gar roe has not been experimentally fed to predatory fish, if future experiments conducted on longnose gar roe show that they cause predatory fish mortality, it would suggest that ichthyootoxin evolved further in longnose gar to protect their roe from predatory fish.
The longnose gar (Lepisosteus osseus) inhabits a wide variety of aquatic ecological niches, occurring frequently in slow moving areas such as backwaters, quiet currents, and sluggish areas of water close to vegetation (Goodyear 1967).They tend to prefer shallow and weedy areas of medium to large rivers (typically over 12m in width), lakes, estuaries, reservoirs, and can occasionally be found in the brackish waters of coastal inlets and deeper stretches of bayou habitat along the Gulf Coast (Goodyear 1967). Some longnose gars are even known to use sewers to travel from larger bodies of water such as lakes and rivers to smaller ponds and streams. Despite this great variation in habitat use, however, they tend to prefer areas with wide floodplains where seasonally shallow waters provide their young with some protection from predators (Becker, 1983).
Spawning L. osseus often congregate near the surface in littoral shallows, and spawning can occur over vegetated beds on river banks, in grasses and weeds in shoal water in lakes, or near stone piles of railroad bridges or gravel bars in streams.The eggs require areas of low flow water to keep from getting washed away, as they have a minimal adhesive substance keeping them in place. As they mature, young gar tend to occupy shallows, and larger individuals can be found in deeper waters of pools, backwaters, and oxbows of medium to large rivers and lakes (Becker, 1983). For many gar species, human construction and agriculture have dramatically altered their riverine ecosystems.The loss of aquatic vegetation, increase of sedimentation, and contamination in the freshwater systems in North America has largely eliminated their preferred spawning habitats (Jean, 1946). This loss of habitat has contributed to population declines across much of the animal’s range.
Gars have unique physical modifications that allow them to survive in limnetic environments typically unsuitable for other species of fish. They are capable of gulping air into their swim bladders, which provides a secondary method of oxygen intake that most fish do not possess (Rahn et al. 1971). Because they do not exclusively rely on getting oxygen through their gills, gars can survive in waters with oxygen levels too low for many other species, and sometimes even through temporary, total oxygen depletion.
In general, the family Lepisosteidae is currently known to inhabit fresh, brackish, and occasionally marine waters in Eastern North America, Central America, and Cuba (Wiley, 1976). Within North America, the longnose gar is found east of the Mississippi River from Canada all the way down to Florida, and as far west as Kansas, Texas, and southern New Mexico. Lepiosteus osseus inhabits the drainage basins of the Mississippi River, Lake Michigan, and Lake Superior, and is extremely common in Mississippi, Ohio and Wisconsin rivers. However, fossils indicate that the family’s range in used to be much larger. Fossil Lepisostids from the Mesozoic and Cenozoic eras are found in Europe, India, South America and North America (Wiley, 1976).
Extensive studies on the distribution of L. osseus have been completed in Wisconsin, indicating specific rivers and lakes in which they can be found (Haase, 1969 and Becker, 1983). These studies in Wisconsin also found different substrates associated with L. osseus habitat. The frequency of substrates associated with L. osseus is 29% gravel, 25% sand, 17% mud, 13% clay, 8% silt, 4% rubble, and 4% boulders, with the percentage values representing the proportion of time longnose gar are found in habitats composed of the substrates (Becker, 1983).Current research on the longnose gar is lacking, so it is unclear whether this frequency distribution is uniform across all habitats.
The longnose gar (Lepisosteus osseus) is a member of the family Lepisosteidae, a group of freshwater fishes collectively known as garfish that are most closely related to bowfins in the infraclass Holostei. Within the genus Lepisosteus, which contains four species, the longnose and shortnose (Lepisosteus platostomus) gars are more closely related to each other and are sister taxa to the Spotted (Lepisosteus oculatus) and Florida (Lepisosteus platyrhincus) Gars. The longnose gar is primarily a freshwater fish, with some populations existing in brackish waters and very few in marine environments. Typical gar habitat consists mainly of slow moving rivers, lakes, and other bodies of water where water is shallow and vegetation is present. The longnose gar is found in North America, from southern portions of Quebec all the way down to Cuba. Total adult population size is unknown but is likely greater than 100,000. In comparison to other gar species, the longnose gar is easily distinguishable by its extremely long and narrow snout. Aside from snout length, a single row of sharp villiform or small and slender teeth in the upper jaw allows this species to be easily distinguished. The typical coloration of an adult longnose gar is olivaceous brown dorsally and laterally, which fades into a pale yellow or white ventrally. The longnose gar also has spots on its dorsal, anal, and caudal fins. Similar to other gars, longnose gar roe (external eggs) contains ichthyootoxin, but scientists are uncertain as to whether the toxin has evolved for egg defense or as a byproduct of other processes during development. Crayfish that eat longnose gar roe are negatively affected and can die, but other natural predators, like sunfish, are not affected. Gars are generally considered nuisances by fisherman because of their consumption of and competition with game species and their tendency to become entangled in nylon nets. Gars are carnivores but not necessarily strict piscivores. The diet of these nocturnal hunters consists of smaller fish such as herrings and shads but will also include insect larvae until gars have reached adult age. Gars both feed and breed in shallow waters. Female gars shed their eggs in occupied nests of smallmouth bass, allowing male smallmouth bass to provide parental care and protection that they themselves do not provide.
Lepisosteus osseus has been present in North America for over 100 million years, and is currently distributed throughout the eastern two-thirds of the United States (Johnson and Noltie, 1997, Sutton et al., 2009). Populations inhabit watersheds in the St. Lawrence River drainage, the Atlantic coast from New Jersey to Florida, the Great Lakes and Mississippi River system, and as far west as the Rio Grande River drainage (Gilbert and Williams, 2002). Longnose gar typically inhabit freshwater, although individuals have been caught at salinities as high as 33 practical salinity units (1 psu=1g/kg), (Gandy et al., 2012). Longnose gar occurs naturally through Florida, but there is no record of its presence in natural habitats in extreme southern Florida, including the Everglades. In southern Florida they only appear in man-made canals. The source population for the gars in the canals is hypothesized to be from Lake Okeechobee due to its connectivity to south Florida’s canals, but the exact source is still unknown (Gandy et al., 2012). Total adult population size is unknown but likely greater than 100,000 across the entire range (Page and Burr 2011).
Reproduction takes place from April to August, varying with temperature differences in different geographic areas (McGrath et al., 2012). During reproduction, longnose gars migrate to small, clear, faster moving streams to spawn. Even lacustrine longnose gars make such migrations, traveling into lake tributaries to spawn (McGrath et al., 2012). Spawning migrations are triggered by changes in temperature. Once lake temperatures pass a minimum threshold between 15°C and 16.7°C, longnose gars begin migrating to their stream spawning sites (Johnson and Noltie, 1997). During spawning one female is usually accompanied by two to four males that swim alongside her. She releases her eggs, which are fertilized by the males before sinking to the bottom and sticking to the substrate. Egg counts can range from 30,000 to 77,000 from a single fish during a spawning event; these egg counts are positively correlated to fish length (Holloway, 1954). The eggs then hatch in three to nine days, depending on water temperature (Goddard 2010).
In a river population of longnose gars, the average age is between 3 and 7 and individuals can live to be up to 16 years old. Longnose gars are estimated to live anywhere between 4 and 10 years (Sutton et al., 2009) and the age of reproductive maturity is estimated to be from 3 to 4 years old for males while females do not mature until 6 years (Goddard 2010). Residence times at spawning sites range from 15 to 94 days, with males staying longer than females (McGrath et al., 2012). But, complete residency times from this particular study were underestimates because it is unknown when the fish first arrived at the spawning site ((McGrath et al., 2012). After spawning, individuals have been recorded relocating from freshwater regions, traveling through brackish water, to another freshwater region at distances up to 74 km (McGrath et al., 2012). Juvenile gars primarily use shallow backwater pools that support aquatic macrophytes. Adults use these areas as well as larger deeper riverine pool habitats (Sutton et al., 2009).
The sex ratio of adult spawning longnose gar populations is male biased (between 1.67:1 to 2.07:1). This is statistically significantly skewed in comparison with populations assessed outside of the spawning season, in which the sex ratio is closer to 1:1 (Johnson and Noltie 1997).
Gars are well known among fishermen and boaters in North America because they regularly occur in the same areas as game fish and are frequently spotted “breaking” the surface (a behavior associated with gulping air), making them much more visible to fisherman than other species. Historically, gars have been regarded as a nuisance species to fisherman because they can damage lures and nets with their small sharp teeth and are considered predators of more desirable game fish.They have been studied very little compared to other fish, even though recreational and commercial fisheries currently exist for several species of gar.Because of their predation of game fish, gar management has long emphasized removing the species (Johnson and Nolte, 1997). However, other recent management consideration has promoted higher populations of gars as a possible means of controlling the overpopulation of sunfish and yellow perch (Niemuth et al., 1959).
Threats to Lepisosteus osseus populations are mainly the result of human manipulation of aquatic ecosystems. The species is also affected by overfishing via bycatch, habitat loss, dams, road construction, pollution, and other human caused destruction of these systems. The damage to the shorelines of aquatic ecosystems can be extremely harmful to their breeding process, since eggs are generally laid in shallow water and young gar spent a majority of their time in shallow vegetated areas (Scarnecchia, 1992). The species is also often unintentionally caught in many types of fishing nets and seines. In some states, L. osseus has been classified as a threatened species (South Dakota, Delaware, and Pennsylvania).
About the longnose gar, in the flowery language of the era, Forbes and Richardson (1920) stated: “[the longnose gar] is a wholly worthless and destructive nuisance in relation to mankind. It has, in fact, all of the vices and none of the virtues of a predaceous fish.” That is, longnose gar were long considered rough fish (or “trash fish”) due to how undesirable they were to anglers and sport fisherman (Spitzer 2010).In recent times, however, the longnose gar has become more of a sport fish and some people have found their meat to be appetizing.There is a commercial fishery for longnose gar in Arkansas, and the species has been taken from the Wisconsin and Mississippi rivers as well (Becker, 1983). The typical method of purposeful capture is entangling the teeth in nylon threads of a net or by bow fishing using specialized archery equipment. In Texas, specimens in excess of 80 pounds have been landed using a bow and arrow (Texas Parks and Wildlife). Some ethnic groups in Louisiana and in the southern US eat the meat of longnose gar, forgoing filleting (due to the hassle of sorting through lots of small bones) to roll the meat into “gar balls”.
It should be noted that gar eggs may be highly toxic to mammals and birds if ingested (Niemuth et al., 1959).The toxin has yet to be identified, but current speculation is that the toxin is a protein of some kind, potentially an algaecide or fungicide.Surprisingly though, gar eggs have not been shown to be toxic to any other fish species.
Gar skins consist of ganoid scales, which provide a sturdy, bony frame, and thus have been used to a small extent as luxury items; e.g., picture frames, purses, and fancy boxes (Forbes and Richardson, 1920). The hard bony plates in the skin were also used by Native Americans as arrowheads, and native Caribbean people used the skin for breastplates. There are records of Creek and Chickasaw people having ritual “Gar Fish Dances”.The Gar Fish Dance is considered the only true surviving Chickasaw dance and occurs during a ceremony in which the teeth of a gar are used in purification rituals (Spitzer 2010). Even early American pioneers have records of covering the blades of their plows in gar skins.
Uzunburun zirehli (lat. Lepisosteus osseus) - kayman balığı cinsinə aid heyvan növü.
Der Gemeine Knochenhecht (Lepisosteus osseus) oder Langschnauzen-Knochenhecht ist ein einzelgängerischer, bis zwei Meter langer Raubfisch.
Die Tiere haben die typische langgestreckte Gestalt aller Stoßräuber. Die Schnauze macht mehr als zwei Drittel, manchmal auch 80 %, der Kopflänge aus. Jungtier und viele Ausgewachsene Fische tragen ein Band, oder ein Fleckenmuster entlang den Flanken. Rücken- und Afterflosse sitzen weit hinten am Rumpf und bilden zusammen mit der heterocerken Schwanzflosse das Antriebsorgan.
Er lebt im Westen der USA von Wisconsin, dem Eriesee und den Flüssen Vermonts bis zum Rio Grande und Florida. Ein ehemaliges Vorkommen im Michigansee ist erloschen. Sie halten sich normalerweise zwischen Vegetation auf, wo sie als Stoßräuber auf Beute lauern. Ausgewachsene Fische gehen auch ins Brackwasser, vor allem in den Wintermonaten.
Der Gemeine Knochenhecht laicht in Gruppen aus einem Weibchen und zwei bis acht Männchen. Die Männchen zeigen dabei keine Aggression gegeneinander. Es werden bis über 35.000 Eier in flaches Wasser gelegt. Die Eier sind giftig und sollen kurzes Austrocknen vertragen. Nach dem Schlupf heften sich die Larven mit einem Saugnapf an der Stirn zunächst senkrecht an Wasserpflanzen oder Steine, bis der Dottersack aufgezehrt ist. Danach ernähren sie sich zunächst von kleinen Krebstieren. Ab einer Länge von fünf Zentimeter jagen sie andere kleine Fische.
Der Gemeine Knochenhecht (Lepisosteus osseus) oder Langschnauzen-Knochenhecht ist ein einzelgängerischer, bis zwei Meter langer Raubfisch.
Taxonavigaçion
Lepisosteus osseus
The longnose gar (Lepisosteus osseus), also known as longnose garpike or billy gar, is a ray-finned fish in the family Lepisosteidae. 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 a spiral 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 with ganoid 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 and Central 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 by Carl Linnaeus (1758), who gave it the name Esox osseus.[7] The generic name Esox, which is for pike, was later changed to Lepisosteus, the genus for slender gars. Lepisosteus osseus (Linnaeus, 1758), the scientific name for longnose gar, originated by combining lepis, which is Greek for scale, and osteos, 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 highly vascularized swim 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 the Pleistocene, where they were discovered in the Kingsdown Formation in Meade County, KS and date back to the Irvingtonian (1.8 - 0.3 Mya).[12] Longnose gar are found in Central America, Cuba, North America, and the Isla de la Juventud.[13]
Longnose gar are frequently found in fresh water in the eastern half of the United States, but some gar were found in salinities 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 occasionally insects and small crustaceans; they mostly feed at night.[16] In most studies of adult L. 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] In Florida, their diet consisted mainly of fishes, with gizzard shad, bullhead catfish, and small bluegill particularly common.[18] In Missouri, fishes made up 98% of the diet with shiners being the most common prey.[19] In some lakes, adult longnose gar may consume large numbers of sunfish. Menhaden are a major food source along coasts where L. 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] 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. Adult longnose gar are considered apex predators in their aquatic habit, and have few predators, which include humans and in the southern reaches of their range the American 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, or smallmouth 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, 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, and Pennsylvania).[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 to overfishing, habitat loss, dams, road construction, pollution, and other human-caused destruction of the aquatic systems. Because of their long lifespans and older sexual maturity age, factors affecting their reproduction is 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]
US distribution of longnose gar ,_published_1731-1743,_NGA_53845.jpg)
Mark Catesby, The Green Gar Fish (Esox osseus), published 1731-1743. An eighteenth-century print with Linnaeus' original name for the longnose gar. 
Longnose gar (‘’L. osseus) 
Georgia Aquarium The longnose gar (Lepisosteus osseus), also known as longnose garpike or billy gar, is a ray-finned fish in the family Lepisosteidae. The genus may have been present in North America for about 100 million years. References are made to gars being a primitive group of bony fish because they have retained some primitive features, such as a spiral 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 with ganoid 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. 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 and Central 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.
El pejelagarto narigudo, catán narigudo, catán aguja, pez picudo o pez caimán (Lepisosteus osseus) es una especie de actinopterigio holósteo de la familia Lepisosteidae. Se encuentra en la mitad este de Norteamérica y en algunos afluentes del río amazonas. Es una especie apreciada en la pesca.
Su origen se remonta a millones de años atrás, cuando dominaba en los lagos y ríos de Canadá, Estados Unidos y Norte de México, aunque en los últimos 3 siglos su hábitat y su número ha bajado por consecuencia de la actividad humana.
El pejelagarto narigudo es un pez de gran tamaño, que llega a medir entre 60 y 200 cm. Puede llegar a pesar hasta 40 kg. La coloración varía, aunque el cuerpo suele ser de color marrón u oliva, blanco en la parte inferior, con manchas oscuras en el cuerpo y las aletas. Los ejemplares juveniles presentan una característica franja negra horizontal que recorre todo el cuerpo, que desaparece con la edad. Presenta una forma alargada y estilizada. La cabeza consta de grandes ojos y un hocico alargado que se asemeja al de un cocodrilo (de ahí le viene el nombre de pez caimán), con numerosos dientes afilados. La mandíbula superior es más larga que la inferior. El cuerpo está cubierto por grandes escamas óseas no superpuestas. Las aletas dorsal y anal se sitúan cerca de la aleta caudal. No tienen espinas, y presentan pocos radios. La aleta caudal es heterocerca. La vejiga natatoria está adaptada para respirar aire. La especie presenta dimorfismo sexual: las hembras son más grandes y redondeadas que los machos, más pequeños y alargados.
El pejelagarto narigudo es un depredador agresivo que se alimenta de peces y crustáceos, a los que atrapa con sus largas mandíbulas provistas de dientes afilados. Ocasionalmente se alimenta de moluscos. Esta especie habita en el curso bajo de los ríos y en aguas estancadas con abundancia de plantas acuáticas. Se sitúa cerca de la superficie, prefiriendo espacios abiertos. Tolera altas temperaturas y puede respirar aire si el agua donde vive es pobre en oxígeno disuelto. Es un pez poco activo, que permanece quieto a la espera de presas
La hembra efectúa la puesta entre finales de primavera e inicios de verano, aunque en latitudes inferiores la puesta se efectúa en abril. La hembra deposita unos 8000 huevos por kilogramo de masa. Los huevos eclosionan en una semana, y las crías permanecen adheridas a las plantas acuáticas. Se alimentan en un principio de insectos y crustáceos, aunque incorporan peces a su dieta, practicando incluso el canibalismo. Las crías crecen con rapidez, alcanzando los 30 cm al año de vida. Esta especie puede alcanzar una edad de entre 17 y 20 años
El pejelagarto narigudo es una especie que se mantiene en cautividad en acuarios. Ocupa la sección superior del acuario, y precisa una instalación grande. Se alimenta de presas vivas y muertas, por lo que conviene mantenerlo separado de peces pequeños. No se ha conseguido reproducir en cautividad. Por otra parte, es una especie que se pesca. Se suelen utilizar métodos especializados para capturarlo, como la pesca submarina. Para la pesca con caña se suele utilizar un anzuelo circular, y pescar por la noche, pues esta especie es de hábitos nocturnos.
Actualmente rige un impedimento de 3 años que prohíbe su captura para permitir que su especie se recupere, además de que la Secretaria de Agricultura, Ganadería, Desarrollo Rural, Pesca y Alimentación (SAGARPA), la Universidad Autónoma de Nuevo León (UANL) y el Instituto Tecnológico y de Estudios Superiores de Monterrey (ITESM) mantienen programas de reproducción en cautiverio del pez para luego liberar a la crías en ríos y lagunas.
La cual decrecénta el número de especies en México.
El pejelagarto narigudo, catán narigudo, catán aguja, pez picudo o pez caimán (Lepisosteus osseus) es una especie de actinopterigio holósteo de la familia Lepisosteidae. Se encuentra en la mitad este de Norteamérica y en algunos afluentes del río amazonas. Es una especie apreciada en la pesca.
Su origen se remonta a millones de años atrás, cuando dominaba en los lagos y ríos de Canadá, Estados Unidos y Norte de México, aunque en los últimos 3 siglos su hábitat y su número ha bajado por consecuencia de la actividad humana.
Lepisosteus osseus Lepisosteus generoko animalia da. Arrainen barruko Lepisosteidae familian sailkatzen da.
Lepisosteus osseus Lepisosteus generoko animalia da. Arrainen barruko Lepisosteidae familian sailkatzen da.
Luuhauki (Lepisosteus osseus) on luuhaukien heimon yleisin laji, jota tavataan laajalla alueella Pohjois-Amerikassa aina Suurilta järviltä Floridaan ja New Mexicoon. Se viihtyy järvissä ja hitaasti virtaavissa joissa vaikka onkin vahva uimari. Se pystyy elämään myös vähähappisissa vesissä käyttämällä uimarakkoaan lisähengityselimenä, jolla se pystyy hengittämään ilmakehän happea.
Luuhauki on n. 1,5 metrin pituinen, solakka ja kapeakuonoinen kala, jonka selkä- peräevät ovat vastatusten lähellä pyrstöevää. Selkäpuoli on tummanruskea ja vatsapuoli vaaleampi. Evät ovat ruskeiden täplien kirjomat ja suu on täynnä teräviä hampaita. Se muistuttaa huomattavasti haukea (Esox lucius), vaikka ei olekaan tälle sukua. Lisäksi se erottuu hauesta toisiinsa niveltyneiden paksujen kiillesuomujensa ansiosta mikä on kaikille heimon lajeille yhteinen piirre.
Luuhauki on ahnas peto, joka vaanii muita kaloja kasvillisuuden seassa ja ampaisee nopeasti niiden kimppuun. Suurena petona sen ainoa luontainen vihollinen on mississippinalligaattori (Alligator mississipiensis).
Kutu tapahtuu keväällä matalassa vedessä. Naaras laskee kerralla n. 30 000 mätimunaa, jotka tarttuvat vesikasveihin. Munia ei vartioida, sillä ne sisältävät myrkyllistä ainetta, joka suojaa niitä mädinsyöjiltä.
Luuhauki (Lepisosteus osseus) on luuhaukien heimon yleisin laji, jota tavataan laajalla alueella Pohjois-Amerikassa aina Suurilta järviltä Floridaan ja New Mexicoon. Se viihtyy järvissä ja hitaasti virtaavissa joissa vaikka onkin vahva uimari. Se pystyy elämään myös vähähappisissa vesissä käyttämällä uimarakkoaan lisähengityselimenä, jolla se pystyy hengittämään ilmakehän happea.
Lepisosteus osseus
Le lépisosté osseux (Lepisosteus osseus) est une espèce de poissons de la famille des Lepisosteidae, vivant en Amérique du Nord, dont les œufs ont la particularité d’être toxiques.
Étymologie : Lepisosteus : écaille d’os ; osseus : osseux
Le lépisosté osseux est un grand poisson allongé et cylindrique qui mesure habituellement entre 60 et 90 cm. Le museau est typiquement mince, très effilé au bout arrondi et muni de 1 400 petites dents acérées. Les narines sont disposées au bout du museau, qui dépasse largement la mâchoire inférieure. Les nageoires sont marquées de grands points foncés. La nageoire dorsale, unique, haute mais à base courte, est insérée loin en arrière. La caudale est arrondie. Les écailles sont modérément grandes, épaisses, osseuses (ganoïdes), non imbriquées mais articulées avec rainures et languettes, formant ainsi une véritable armure. On compte 61 à 65 écailles le long de la ligne latérale. Les vertèbres des lépisostés sont remarquables et uniques en ce qu’elles sont convexes à l’avant et concaves à l’arrière.
L’adulte est brun ou vert foncé sur le dos et les flancs supérieurs, les faces latérales sont vert pale ou argent mêlé de blanc en dessous. Le corps porte des taches éparpillées d’égales grandeurs, surtout à partir des pelviennes vers l’arrière. Les jeunes portent une longue bande latérale sinueuse, brune ou noire, à partir du museau jusqu’à la caudale. Cette bande disparaît graduellement par endroits en laissant de gros points.
Le lépisosté osseux affectionne les zones herbeuses et peu profondes des lacs, des grandes rivières aux eaux chaudes, les réservoirs, les bayous et les estuaires. Il s’aventure aussi en eaux saumâtres mais très rarement en milieu marin. Les jeunes préfèrent se cacher et chasser dans les remous autour de végétaux submergés.
D’octobre à avril, le lépisosté osseux cherche les grandes profondeurs des rivières pour passer l’hiver : il reste alors presque complètement immobile, ne remontant ni pour respirer, ni pour se nourrir.
Le lepisosté osseux est largement distribué en Amérique du Nord, principalement dans l’Est : ainsi, on le retrouve dans les eaux du fleuve Saint-Laurent au Québec au Nord, le long des côtes américaines, dans tous les Grands Lacs (excepté le Lac Supérieur) jusqu’au centre de la Floride, jusqu’au Montana et le Wyoming à l'ouest, et le Texas et le Nord du Mexique au sud.
Les mâles sont sexuellement matures vers 3 ou 4 ans, les femelles ne le sont que vers 6 ans. La montaison coïnciderait avec les crues de printemps : en effet, les lépisostés fraient en groupe à la fin du printemps, d’avril à août selon les régions, en eau douce, dans les régions peu profondes des lacs et des grandes rivières. Ils utilisent un nid rudimentaire, sans le construire réellement, à une profondeur de 2 pieds (60 cm) sur fond recouvert de tiges courtes de plantes aquatiques. Durant la fraie, une femelle est habituellement accompagnée de 2 à 4 mâles, jusqu’à 15. Lorsque la femelle est prête, elle les entraîne dans un mouvement elliptique une quinzaine de minutes avant la ponte. Pendant ce temps, les mâles frôlent du museau les surfaces ventro-latérales de la femelle et remontent fréquemment à la surface. Finalement, le groupe se stabilise, la tête en bas avant de libérer violemment les œufs et le sperme. Une femelle pond en moyenne 27,800 œufs (jusqu’au record de 77,156 œufs chez un lépisosté de Floride de 142 cm). Lepisosteus osseus ne fait preuve d'aucune attention parentale, mais des études ont montré qu’il pouvait pondre dans les nids de l'achigan à petite bouche (Micropterus dolomieu), le mâle de l'achigan protégeant alors les œufs du lépisosté en plus des siens. (Goff, 1984).
Les œufs sont de grande taille, 2 à 3 mm et de coloration vert foncé. Ils sont visqueux et se collent à la végétation aquatique peu après la ponte. Les œufs éclosent en 3 à 9 jours dans des eaux chaudes. Les jeunes lépisostés mesurent 8 à 10 mm à l’éclosion et possèdent un bourrelet adhésif qui leur permet de se fixer à la végétation jusqu’à ce qu’ils aient consommé le sac vitellin (vers 9-11 jours). Ils mesurent alors 18 à 20 mm, peuvent se maintenir à l’horizontale, prennent leur première respiration aérienne et commencent à se nourrir.
Les jeunes croissent très rapidement, jusqu’à 6 fois plus vite que tout autre espèce de poissons d’eau douce de l'Amérique du Nord : des études en aquarium ont montré qu’ils gagnaient ainsi 3,3 mm et 1,8 g par jour pourvu que la nourriture soit abondante (Riggs and Moore, 1960). Le lépisosté osseux peut ainsi atteindre une taille considérable, le record de pêche étant un spécimen d'1,8 m et de 22,8 kg, capturé au Texas le 30 juillet 1954.
Il existe une différence de croissance selon les sexes : les femelles croissent plus rapidement, atteignent une taille plus importante et vivent plus longtemps que les mâles. Si le ratio mâles/femelles atteint 262/100 en début de vie, il tombe à 8/100 à 10 ans. Ainsi, les femelles peuvent atteindre 20 ans quand les mâles ne dépassent à peine la dizaine d’années. Le record de longévité serait de 36 ans en captivité (fishbase)
Les lépisostés, comme cette espèce, ont la capacité de respirer l’air à la surface grâce à la modification de la vessie natatoire en vessie gazeuse : l’épithélium s’y est soulevé en replis richement vascularisés, permettant des échanges gazeux en milieu aérien. Ce poumon primitif leur permet de survivre aisément dans les étangs d’eaux stagnantes, les marécages et les canaux dans la partie sud de leur aire de répartition, voire de survivre plusieurs heures hors de l’eau.
Ce sont surtout les juvéniles de l’espèce qui subissent la prédation, en particulier par des poissons plus gros. Les adultes, de par leur grande taille et leurs écailles ganoïdes, ont peu de prédateurs, sauf éventuellement lorsqu’ils sont hors de l’eau. Dans les régions les plus au sud de la présence du Lépisosté, des observateurs ont relevé des prises de Lepisosteus osseus par les alligators (Alligator mississippiensis), mais des études suggèrent qu’il ne s’agit alors que d’événements opportunistes. (McCormack, 1967)
Le lepisosté osseux peut être parasité par des trématodes, des cestodes, des nématodes, des acanthocéphales et par des crustacés. Il est aussi l’hôte du glochidium d’une moule de commerce importante, Lampsilis teres. Ainsi, on infecte artificiellement les lepisostés pour propager la moule.
Malgré cette utilité certaine, les adjectifs pour qualifier le lépisosté osseux sont les mêmes : malfaisant, destructeur, sans valeur, nuisible. Les adultes sont en effet connus pour endommager les filets destinés à pêcher d’autres poissons. De plus, sa chair ne présente aucun attrait particulier. Mais on lui reproche surtout de consommer des poissons de friture ou d’intérêt. Le lépisosté est probablement une espèce vorace, consommant volontiers les poissons de sport et de friture mais il peut n’être qu’une espèce opportuniste et d’autre part, il est possible que ses effets sur les espèces de valeur aient été grandement surestimés. En effet, dans le lac Texoma, 84 % des proies des juvéniles seraient des Menidia beryllina, les poissons de sport constituant moins de 1 % du régime alimentaire (Eschelle, 1968). Mieux, le lépisosté contrôlerait même la surpopulation de perche jaune (Niemuth et al., 1959).
Par ailleurs, le lépisosté osseux a mauvaise réputation à cause de la toxicité de ses œufs, qui sont vénéneux pour l’être humain comme pour tous les autres mammifères et les oiseaux. Ils sont la cause de sévères malaises chez les grands animaux et provoquent la mort chez les plus petits. Toutefois, les œufs ne semblent pas toxiques pour les poissons puisqu’ils ont été retrouvés dans des contenus stomacaux.
Commercialement, le lépisosté osseux n’a pour ainsi dire aucun intérêt pécuniaire : sa chair est fade et ses dérivés limités.
Par contre, il a un certain intérêt sportif. Il faut savoir que le lépisosté osseux n’est protégé par aucune réglementation bien que FishBase le classe en « très haute vulnérabilité ». Il se pêche à la ligne et à l’hameçon, au lacet et à la foëne.
Lepisosteus osseus
Le lépisosté osseux (Lepisosteus osseus) est une espèce de poissons de la famille des Lepisosteidae, vivant en Amérique du Nord, dont les œufs ont la particularité d’être toxiques.
Il luccio dal naso lungo (Lepisosteus osseus Linnaeus, 1758), o pesce dal becco, è un pesce della famiglia dei Lepisosteidi.
Il luccio dal naso lungo misura una lunghezza di 60 - 182 cm e pesa 0,5 - 3,5 kg; FishBase riporta una lunghezza massima di 2 m. Vive in media 17 - 20 anni. Il muso è allungato in un becco sottile munito di numerosi denti ben sviluppati. Il corpo, lungo e cilindrico, è ricoperto da scaglie ganoidi a forma di diamante. L'intero corpo è attraversato da una lunga striscia nera.
Il luccio dal naso lungo è diffuso nei fiumi e nei laghi della metà orientale degli Stati Uniti, dal Quebec meridionale e dalle estreme propaggini meridionali dell'Ontario, nella regione dei Grandi Laghi, al Messico settentrionale. Le concentrazioni più elevate si incontrano però nel Profondo Sud americano, in Texas, Alabama (bacino del Cahaba) e lungo tutto il corso del Mississippi. Predilige acque basse e calde con abbondante vegetazione.
Oltre che il più diffuso, il pesce dal becco è anche il rappresentante della famiglia più noto negli Stati Uniti ed è quindi la specie di cui si conoscono meglio e più dettagliatamente le abitudini. Come gli altri Lepisosteidi, è un animale che ama vivere solitario, preferibilmente nei corsi d'acqua tranquilli e poco profondi, con ampia disponibilità di nascondigli: nel folto dei canneti, tra la vegetazione o sotto tronchi d'albero sommersi, resta infatti immobile in agguato delle prede, senza dare altro segno di vita all'infuori dei lenti movimenti delle pinne pettorali. Con i grandi occhi scruta attentamente all'intorno e, non appena ha adocchiato una preda, comincia ad avvicinarsi con circospezione, agitando silenziosamente le pinne pettorali e l'estremità della coda, fino a portarsi con il becco all'altezza della vittima; allora, esattamente come un caimano o un coccodrillo, spalanca la bocca e, con un rapido movimento laterale del capo, afferra la preda con i denti aguzzi. Questa viene poi girata e ruotata fino a trovarsi in posizione parallela alle mascelle e quindi inghiottita in un solo boccone. Essendo il palato estremamente elastico, gli archi mascellari possono allargarsi ampiamente, il che permette al pesce dal becco di inghiottire anche prede di grandi dimensioni; in questi casi la parte inferiore del capo assomiglia al sacco giugulare di un pellicano che abbia appena inghiottito un pesce.
Durante i mesi estivi, quando il contenuto in ossigeno dell'acqua subisce una forte riduzione, il pesce dal becco è costretto a rifornirsi di aria direttamente dall'atmosfera: di quando in quando (nei corsi d'acqua particolarmente carenti di ossigeno anche 6 volte in 10 minuti), risale quindi in superficie e, giratosi leggermente di lato, espelle una grande bolla d'aria che fuoriesce gorgogliando dalle aperture branchiali. Tenendo le mascelle ampiamente sporgenti dall'acqua e la bocca leggermente aperta, inghiotte una forte quantità d'aria atmosferica, accumulandola nella vescica natatoria che ha le pareti riccamente vascolarizzate ed è suddivisa in piccole celle (alveoli). Al sopraggiungere della stagione fredda, in ottobre, questi Lepisosteidi si spostano nelle zone più profonde dei corsi d'acqua, ove rimarranno fino ad aprile immersi in una sorta di letargo: quasi completamente immobili giacciono allora sul fondo senza assumere più cibo né portarsi in superficie per respirare.
Nella tarda primavera, tra la metà di maggio e i primi di giugno, o già alla fine di aprile nelle acque caratterizzate da temperature elevate, i pesci dal becco abbandonano le loro dimore invernali per portarsi lungo le rive, in punti poco profondi e possibilmente ricchi di vegetazione, ove verranno deposte le uova. Dopo un cerimoniale amoroso particolarmente turbolento la femmina, che è in genere accompagnata da vari maschi, espelle in diverse fasi successive le uova verdognole, grandi all'incirca 3 mm, che vengono fecondate dai maschi e quindi si fissano al fondo e alle piante acquatiche. Dopo un periodo variabile, a seconda della temperatura dell'acqua, dai 10 ai 14 giorni, i gusci si schiudono lasciando uscire i piccoli che, non avendo la benché minima somiglianza con i genitori, vengono definiti «larve». Lunghi all'incirca 7 mm, sono dotati di un grande sacco vitellino, che ostacola loro i movimenti, e recano anteriormente alla bocca una ventosa munita di numerose piccole verruche, con l'ausilio della quale si tengono fissati alle piante finché non hanno consumato quasi tutto il sacco; inoltre sono privi di branchie esterne. Completamente lasciate a sé stesse, in quanto i genitori non si curano affatto di loro, le larve raggiungono dopo una settimana, durante la quale hanno assorbito parte del sacco vitellino, la lunghezza di circa 9 mm; al contempo, la mandibola si allunga in forma di proboscide, mentre la colonna vertebrale si estende, come un filamento, sopra la pinna caudale. Circa 14 giorni dopo l'uscita dall'uovo, il piccolo pesce dal becco è già in grado di nuotare liberamente e ha assunto un aspetto del tutto simile a quello dei genitori.
In taluni territori, quali la zona dei Grandi Laghi o i vasti bassopiani paludosi della Florida, i Lepisosteidi sono diffusi sovente in numero così elevato che è necessario controllarne e ridurne la popolazione per poter mantenere un effettivo equilibrio nell'attività della pesca.
in acquario si tengono spesso gli esemplari giovani, ma gli adulti sono adatti solo agli acquari pubblici. vanno tenuti da soli o con esemplari selezionati attentamente.
Il luccio dal naso lungo (Lepisosteus osseus Linnaeus, 1758), o pesce dal becco, è un pesce della famiglia dei Lepisosteidi.
De kaaimansnoek of beensnoek (Lepisosteus osseus), is een primitieve beenvis uit de familie Lepisosteidae.
Lepisosteus osseus is te herkennen aan zijn lange bek waarmee hij vissen vangt vanuit een hinderlaag tussen de waterplanten. Zijn langgerekte lichaam is bedekt met grote, ruitvormige ganoïde schubben. De rug- en aarsvin zijn ver naar achteren geplaatst. Op de kop bevinden zich beenplaten. De langgerekte kaken zijn voorzien van een groot aantal scherpe tanden. Hij kan een lengte bereiken van 2 meter en een gewicht tot 15 kg.
Deze vissen hangen meestal bewegingsloos in het water. Komt er een nietsvermoedende prooi binnen bereik, dan slaan ze genadeloos toe en klemmen de prooi soms minutenlang tussen de kaken. Ze zijn niet geliefd bij vissers, omdat ze veel schade kunnen aanrichten aan de netten.
De beensnoek komt voor in de zoetwaterrivieren van Canada tot Panama.
De kaaimansnoek of beensnoek (Lepisosteus osseus), is een primitieve beenvis uit de familie Lepisosteidae.
Multimedia w Wikimedia Commons Niszczuka długonosa[3], niszczuka[4], łuskost[5] (Lepisosteus osseus) – gatunek ryby niszczukokształtnej z rodziny niszczukowatych (Lepisosteidae).
Ciało silnie wydłużone pokryte łuskami ganoidalnymi, długi, wysmukły pysk, grzbiet brązowy, spód jasny. Osiąga do 2 m długości, maksymalna odnotowana masa ciała: 22,8 kg.
Ryba drapieżna, żywi się rybami i skorupiakami.
Niewielkie znaczenie gospodarcze, poławiana przez wędkarzy, spotykana w akwariach publicznych. Ikra jest trująca.
Niszczuka długonosa, niszczuka, łuskost (Lepisosteus osseus) – gatunek ryby niszczukokształtnej z rodziny niszczukowatych (Lepisosteidae).
O gar-bicudo (Lepisosteus osseus), também conhecido como gar-de-nariz-grande, é um peixe actinopterígeo na família Lepisosteidae. Pode ser distinguido das outras espécies de gar por seu focinho, que é mais do que o dobro do comprimento do resto de sua cabeça além de possuir um corpo mais longo, estreito e cilíndrico.
Eles normalmente habitam lagos de água doce, água salobra perto de áreas costeiras, pântanos e remansos lentos de rios e riachos. Eles podem respirar ar e água, o que lhes permite habitar ambientes aquáticos com baixo teor de oxigênio.
O gar-bicudo é encontrado ao longo da costa leste da América do Norte e Central, e varia tão a oeste nos Estados Unidos quanto Kansas, Texas e sul do Novo México. Ele é a única espécie da família Lepisosteidae encontradas no Novo México. Suas populações são estáveis e em algumas áreas abundantes no interior de sua área de distribuição.[1]
O gar-bicudo foi descrito pela primeira vez por Carl Linnaeus (1758), que lhe deu o nome de Esox osseus .[1] O nome genérico Esox, que significa lúcio, foi mais tarde alterado para Lepisosteus, o gênero dos gars. Lepisosteus osseus (Linnaeus, 1758), o nome científico do gar-bicudo, originado pela combinação de lepis, que é grego para escama, e osteos, a palavra latina para óssea. O último faz referência às escamas ganoides em formato romboidal, semelhantes a ossos, que protegem os gars contra a predação.
Fósseis do gênero que datam de 100 milhões de anos atrás (Mya) foram encontrados na África, Ásia, Europa, América do Norte e América do Sul. Nos Estados Unidos, os fósseis das espécies modernas datam do Pleistoceno, onde foram descobertos na Formação Kingsdown no Condado de Meade, KS, e datam do Irvingtonian (1,8 - 0,3 Mya).[2] Longnose gar são encontrados na América Central, Cuba, América do Norte e na Isla de la Juventud .[3]
O gar-bicudo é freqüentemente encontrado em água doce na metade oriental dos Estados Unidos, mas já foram registrados exemplares em águas salobras próximas a áreas costeiras, com níveis de salinidade de até 31 ppt.[4] Seus microhabitats consistem em áreas próximas a árvores derrubadas, afloramentos de pedra e vegetação.[5]
As presas mais comuns do gar-bicudo são pequenos peixes e, ocasionalmente, insetos e pequenos crustáceos. Ele se alimentam principalmente à noite..[6] Gars-bicudos adultos são considerados predadores de vértice em seu hábito aquático, e têm poucos predadores, que incluem humanos e no sul de sua distribuição o crocodilo americano .[1] Eles são mais vulneráveis à predação quando são jovens e são predados por outros gars de tamanho maior, peixes maiores, aves de rapina, tartarugas-mordedoras e cobras-d'água.[7]
O gar-bicudo tem uma vida útil típica de 15-20 anos, com uma idade máxima relatada de 39 anos. Esta longa vida útil permite que a fêmea amadureça sexualmente por volta dos 6 anos de idade. Os machos amadurecem sexualmente logo aos 2 anos de idade. O gar-bicudo é sexualmente dimórfico, sendo as fêmeas maiores do que os machos em comprimento do corpo, peso e comprimento das nadadeiras. Ele geralmente tem um tamanho de ninhada próximo a 30.000, dependendo da proporção peso-comprimento da fêmea; fêmeas maiores têm tamanhos de ninhadas maiores. Elas desovam em temperaturas próximas a 20 °C (68 °F[8] Os ovos têm um revestimento tico, adesivo para ajudá-los aderir a substratos, e eles são depositados sobre pedras em águas rasas, prateleiras rochosos, vegetação, ou ninhos de achigã-boca-pequena.[9] Seu tempo de incubação é de 7 a 9 dias; os jovens gar permanecem na vegetação durante o primeiro verão de vida.[6] o gar-bicudo alcança um comprimento típico de 71 a 122 cm, com um comprimento máximo de cerca de 1,8 m e 25 kg em peso.
Atualmente, nenhum manejo desta espécie está sendo conduzido, nem está listada federalmente como ameaçada, embora alguns estados tenham relatado como ameaçada ( Dakota do Sul, Delaware e Pensilvânia ).[10] No início de 1900, os gars-bicudos eram considerados predadores destrutivos. Logo após esta caracterização, métodos de redução da população foram estabelecidos. O declínio de suas populações se deve à pesca excessiva, perda de habitat, represas, construção de estradas, poluição e outras destruições de sistemas aquáticos causadas pelo homem. Por causa de sua longa expectativa de vida e maior idade de maturidade sexual, os fatores que afetam sua reprodução são um problema para preservá-los.[11] A sobrepesca é um grande problema para este peixe, especialmente quando o peixe não atinge a maturidade sexual devido à fêmea não atingir a maturidade sexual até cerca de 6 anos de idade.
O gar-bicudo (Lepisosteus osseus), também conhecido como gar-de-nariz-grande, é um peixe actinopterígeo na família Lepisosteidae. Pode ser distinguido das outras espécies de gar por seu focinho, que é mais do que o dobro do comprimento do resto de sua cabeça além de possuir um corpo mais longo, estreito e cilíndrico.
Eles normalmente habitam lagos de água doce, água salobra perto de áreas costeiras, pântanos e remansos lentos de rios e riachos. Eles podem respirar ar e água, o que lhes permite habitar ambientes aquáticos com baixo teor de oxigênio.
O gar-bicudo é encontrado ao longo da costa leste da América do Norte e Central, e varia tão a oeste nos Estados Unidos quanto Kansas, Texas e sul do Novo México. Ele é a única espécie da família Lepisosteidae encontradas no Novo México. Suas populações são estáveis e em algumas áreas abundantes no interior de sua área de distribuição.
O gar-bicudo foi descrito pela primeira vez por Carl Linnaeus (1758), que lhe deu o nome de Esox osseus . O nome genérico Esox, que significa lúcio, foi mais tarde alterado para Lepisosteus, o gênero dos gars. Lepisosteus osseus (Linnaeus, 1758), o nome científico do gar-bicudo, originado pela combinação de lepis, que é grego para escama, e osteos, a palavra latina para óssea. O último faz referência às escamas ganoides em formato romboidal, semelhantes a ossos, que protegem os gars contra a predação.
Långnosad bengädda (Lepisosteus osseus) är en fisk i familjen bengäddor som lever i Nordamerika.
En avlång, cylindrisk fisk med lång, spetsig nos[2] och en mun med talrika, spetsiga tänder. Vuxna fiskar har olivbrun kropp med vit buk och ofta mörka fläckar på fenorna; populationer som lever i klart vatten kan även ha fläckig kropp. Ungfiskarna har ett smalt, brunt streck längs ryggen, och ett brett, likaledes brunt band längs sidorna. Rygg- och analfenorna sitter långt bak på kroppen.[3] Ryggfenan har 6 till 9 mjukstrålar, medan analfenan har 8 till 10. Som mest kan arten bli 200 cm lång och väga 22,8 kg, men är vanligtvis betydligt mindre.[4]
Den långnosade bengäddan föredrar stilla eller sakta flytande vatten, som sjöar, reservoarer, långsamma floder eller flodmynningar, även med bräckt vatten.[3] Den förekommer även i kustnära saltvatten. Arten är framför allt aktiv under den mörka delen av dygnet; under dagen uppehåller den sig på grunt vatten, gärna i något gömsle. Den tycker om höga temperaturer och har påträffats i vatten så varmt som 34°C.[2] Varma dagar eller nätter händer det att fisken flyter stilla i vattenytan, något som även tjänar som ett sätt att smyga sig på födan.[5] Denna består främst av fisk; speciellt ungfiskar tar även mindre kräftdjur och insekter, framför allt larver och puppor av tvåvingar. Förutom att använda gälarna, kan arten även andas atmosfäriskt syre med hjälp av sin simblåsa, som är rik på blodkärl, ansluten till svalget och fungerar som en lunga. I fångenskap har honorna av den långnosade bengäddan blivit 30 år gamla; i det fria kan de nå en ålder av 22 år. Hanen blir knappast äldre än 17 år.[3]
Arten har inte många fiender på grund av sina kraftiga, sega fjäll, men det har förekommit att den angripits av mississippialligator.[3]
Arten leker under vår och sommar när vattentemperaturen ligger mellan 18 och 21 °C. Leken sker i grunda vatten med grus- eller klippbotten.[2] I samband med parningen närmar sig upp till 15 hanar en hona som, om hon är villig, simmar runt i en oval i upp till 15 minuter innan själva parningen sker. Under denna rundsimning nafsar hanarna henne upprepade gånger. Deltagarna stiger också ofta till ytan och snappar luft. Till slut ställer sig deltagarna med kroppen snett neråt så att nosen snuddar vid botten varvid delagarna avger ägg och mjölke samtidigt som de darrar kraftigt.[3] Mellan 1 100 till över 77 000 ägg läggs av varje hona, beroende på hennes storlek. Äggen kläcks efter 7 till 9 dagar (i undantagsfall så kort tid som 3).[2] Den lagda rommen är giftig.[4]
Arten utövar ingen egen yngelvård; däremot förekommer det att den lägger sina ägg i bon av svartabborre, där fadern bedriver yngelvård. Han kommer på så sätt att bevaka både sin egen och den långnosade bengäddans avkomma.[3]
Utbredningsområdet sträcker sig från Quebec i Kanada over de Stora sjöarna (utom Övre sjön), nordvästra och hela östra USA till Rio Grandes flodområde i Texas och norra Mexiko.[3]
Den långnosade bengäddan anses ha ett gott kött, men är ändå inte föremål för något större fiske. Ett kommersiellt fiske förekommer dock i Arkansas. Den är inte särskilt uppskattad av yrkesfiskare, eftersom det anses att den tar värdefullare fisk.[3] Arten är däremot föremål för ett visst sportfiske; bland annat i Texas fångas den med pil och båge.[6]
Långnosad bengädda (Lepisosteus osseus) är en fisk i familjen bengäddor som lever i Nordamerika.
Lepisosteus osseus là một loài cá vây tia nguyên thủy trong họ Lepisosteidae. Loài cá này có thân dài từ 60–182 cm (24–72 in) và cân nặng 0,5-3,5 kg (1,1-7,7 lb). Kỷ lục thế giới loài này có cân nặng 50,31 kg, bắt được ở sông Trinity, Texas vào năm 1954; ghi nhận của FishBase loài này có kích thước tối đa 2 m (6,6 ft). Tuổi thọ trung bình là 17 đến 20 năm. Mõm dài vào một mỏ hẹp chứa nhiều răng lớn. Chúng có thân hình dài, có hình dạng như một hình trụ, và được bao phủ với vảy có hình kim cương. Nó có một vệt đen dài trên toàn cơ thể.
Loài này được tìm thấy trong các con sông và hồ suốt nửa phía đông của Hoa Kỳ, xa về phía bắc miền nam Quebec và miền nam Ontario ở Ngũ Đại Hồ và sông Ottawa và phía nam cũng như miền bắc Mexico. Số lượng tập trung nhất của loài này được tìm thấy suốt Deep South của Mỹ, Texas, Alabama (hệ thống sông Cahaba), và bất cứ nơi nào dọc theo sông Mississippi. Loài cá này được tìm thấy trong nước ấm cạn, với thảm thực vật phong phú. Lepisosteus osseus đã hiện diện ở Bắc Mỹ cách nay 100 triệu năm.[3]
_-_bass,_bat_fish,_balloon_fish,_etc.jpg)
Bài viết Lớp Cá vây tia này vẫn còn sơ khai. Bạn có thể giúp Wikipedia bằng cách mở rộng nội dung để bài được hoàn chỉnh hơn. Lepisosteus osseus là một loài cá vây tia nguyên thủy trong họ Lepisosteidae. Loài cá này có thân dài từ 60–182 cm (24–72 in) và cân nặng 0,5-3,5 kg (1,1-7,7 lb). Kỷ lục thế giới loài này có cân nặng 50,31 kg, bắt được ở sông Trinity, Texas vào năm 1954; ghi nhận của FishBase loài này có kích thước tối đa 2 m (6,6 ft). Tuổi thọ trung bình là 17 đến 20 năm. Mõm dài vào một mỏ hẹp chứa nhiều răng lớn. Chúng có thân hình dài, có hình dạng như một hình trụ, và được bao phủ với vảy có hình kim cương. Nó có một vệt đen dài trên toàn cơ thể.
Loài này được tìm thấy trong các con sông và hồ suốt nửa phía đông của Hoa Kỳ, xa về phía bắc miền nam Quebec và miền nam Ontario ở Ngũ Đại Hồ và sông Ottawa và phía nam cũng như miền bắc Mexico. Số lượng tập trung nhất của loài này được tìm thấy suốt Deep South của Mỹ, Texas, Alabama (hệ thống sông Cahaba), và bất cứ nơi nào dọc theo sông Mississippi. Loài cá này được tìm thấy trong nước ấm cạn, với thảm thực vật phong phú. Lepisosteus osseus đã hiện diện ở Bắc Mỹ cách nay 100 triệu năm.
長吻雀鳝（Lepisosteus osseus），為雀鳝属的一種鱼类，分布於北美洲東部及中美洲的淡水或半鹹水區域。它是一种活化石，在一亿年前就存在于今天的北美洲附近海域了。[4]
本魚體延長成圓柱形，魚嘴特別細長，體背面為橄欖褐色，腹部白色，體背硬鱗。體佈滿深色斑點，背鰭軟條6至9枚；臀鰭軟條8至10枚，體長可達2公尺。
本魚棲息於淡水河川、湖泊或半鹹水的潟湖、河口，屬肉食性，以甲殼類、魚類、昆蟲等為食，雌魚在巢中卵，由雄魚守護著卵即孵化的幼魚。
可為遊釣魚或觀賞魚，卵有毒。
这是一篇小作品。你可以通过编辑或修订扩充其内容。 
ロングノーズガー（ロングノウズガー[1]、英語: Longnose gar、学名：Lepisosteus osseus）はガー科のレピソステウス属に含まれる淡水魚の1種。種小名の osseus はラテン語で"骨"を意味する。
1758年にリンネによって記載された。ガー目のうちでは、最も早く記載された種で、レピソステウス属のタイプ種でもある。
分布域はガーの中で最も広く、かつ最も北まで分布する。 北端はカナダのケベック州、南端はメキシコ北部にあたる[2]。河川では水生植物が多く流れの穏やかな場所が生息場所となる[3]。大規模な河川に多い。湖では、もっとも北に位置するスペリオル湖を除く、五大湖にも生息する。汽水域にも生息している。
レピソステウス属に含まれる4種のうちでは最大になり、全長2m、体重22.8kgの記録がある。また、ガーの中で最長の吻をもつことや細長い体が特徴として挙げられる。体形がニードルガー[4]（英語: Freshwater garfish、学名：Xenentodon cancila、ダツ目ダツ科に含まれる）に類似するが、系統はまったく異なる。
頭部の形状がガビアル（ワニ）に似ていることから、Lepisosteus gavial Lacepède, 1803という学名がつけられたこともあった。細長い吻は水の抵抗を減らし、動きが速い小魚を捕らえることに適している。収斂進化の一例ともいえる。一方で、対照的な吻をもつアリゲーターガーは、動きが鈍い大型魚を捕えることに向いている。
浮き袋が肺の機能をもち、空気呼吸ができるため、水中が無酸素状態でも生存できる。しかしその一方で、空気呼吸ができない魚に比べ鰓呼吸の機能は低く、それだけでは生存できない。これは、全てのガーやハイギョ、カムルチーなどにもいえることである。実際に、水面とふたの間の隙間が塞がったため、空気呼吸ができない状態に陥り、死亡した例がある[5]。
北部の個体群をL. osseus oxiryncus（ノーザン・ロングノーズガー）、南部の個体群をL. osseus osseus という、2つの亜種に分けられることもある。
食性は、他のガーと同じく肉食性で、主になどの小型の魚類や甲殻類を食べる。吻が細いため大きな獲物を捕獲することはできない。
繁殖期は地域によって異なるが、4月下旬ごろに群れをなして河川を遡上する。5月下旬から6月上旬にかけて産卵する。1個体のメスと複数のオスによって行われる[6]。場所は河川における浅い場所で、水生植物やメスが掘ったくぼみに産み付けられる。1個体で約27,000個の卵を産む。卵は川底の石に粘着する。
オスは約11年、メスで約22年生きる。現存する世界最高齢個体（タイ記録）は、1977年3月1日産まれ（日本産）のもので、2013年現在（36歳）も神戸市立須磨海浜水族園で飼育される[7]。日本国内で飼育される魚類の中でも最高齢である[7]。体長約50㎝と小さく、性格はおとなしいとされる[7]。1995年の阪神大震災では、停電による酸欠で多数の魚類が死亡する中、ガー特有の肺呼吸で生き延びたという[7]。1977年の産卵成功は世界初の繁殖でもある[7]。
ロングノーズガー（ロングノウズガー、英語: Longnose gar、学名：Lepisosteus osseus）はガー科のレピソステウス属に含まれる淡水魚の1種。種小名の osseus はラテン語で"骨"を意味する。
