The Cuban gar (''Atractosteus tristoechus''), also known as the manjuarí, is a

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...

in the family

Lepisosteidae Gars are members of the family Lepisosteidae, which are the only surviving members of the Ginglymodi, an ancient holosteian group of ray-finned fish, which first appeared during the Triassic, over 240 million years ago. Gars comprise seven livin ...

. It is a tropical, freshwater species, although it also inhabits

brackish Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estu ...

water. It is found in rivers and lakes of western

Cuba Cuba ( , ), officially the Republic of Cuba ( es, República de Cuba, links=no ), is an island country comprising the island of Cuba, as well as Isla de la Juventud and several minor archipelagos. Cuba is located where the northern Caribbea ...

and the Isla de la Juventud. The flesh of the fish is edible, but the eggs are poisonous for humans.Lee, D.S., S.P. Platania and G.H. Burgess, 1983. Atlas of North American freshwater fishes, 1983 supplement. Occasional Papers of the North Carolina Biological Survey no. 1983-6. North Carolina State Museum of Natural History, Raleigh, N.C. 67 p. Cuban gar spawn seasonally in the floodplains of large rivers.Dean B. (1895) The early development of gar-pike and sturgeon. ''Journal of Morphology'' 11, 1–53.

Behavior

Cuban gar typically hunt alone and avoid other members of their species. The exception to this is during spawning season, when larger parties of around 20 gar form to hunt. Sometimes, the groups break up into smaller groups, and two to eight males accompany a female. ''Atractosteus'' gar species generally have sex ratios skewed towards males (in the cases of tropical gar or

alligator gar The alligator gar (''Atractosteus spatula'') is a ray-finned euryhaline fish related to the bowfin in the infraclass Holostei . It is the largest species in the gar family, and among the largest freshwater fish in North America. The fossil ...

), although research has yet to show this trend in the Cuban gar.

Morphology

Adult Cuban gars are typically around in length, but can grow as large as . There is no known variance in length relative to sex. This places it as the second largest extant species of gar, after the alligator gar. The Cuban gar, along with other species of gar, is also notable for its high tolerance of high

ammonia Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous was ...

and

nitrate Nitrate is a polyatomic ion A polyatomic ion, also known as a molecular ion, is a covalent bonded set of two or more atoms, or of a metal complex, that can be considered to behave as a single unit and that has a net charge that is not zer ...

levels in water, its ability to breathe some atmospheric air in absence of sufficiently oxygenated water, and its disease resistance.

Larval development

After hatching, Cuban gar larvae undergo three stages of

organogenesis Organogenesis is the phase of embryonic development that starts at the end of gastrulation and continues until birth. During organogenesis, the three germ layers formed from gastrulation (the ectoderm, endoderm, and mesoderm) form the internal org ...

and development: Attached (days 1-3), transitional (days 4-10), and free-swimming (days 11-18).Comabella, Y., Mendoza, R., Aguilera, C. et al. Fish Physiol Biochem (2006) 32: 147. https://doi.org/10.1007/s10695-006-0007-4 During the attached stage, the larvae develop rudimentary intestines, stomachs, pancreases, and esophagi that help the larvae transition from feeding off the egg yolk to normal feeding, which begins during the transitional phase. The transitional phase is marked by further development of these organs and a lack of obvious yolk. During this phase, teeth also develop. Once separation occurs between the stomach and intestines—increased organ size and complexity, and completely exotrophic behavior has arisen—the larvae are considered “free swimming”. While they are larvae, Cuban gar grow from around in length in the attached phase, to in length in the free-swimming phase.

Ecology

Like other species of gars, Cuban gar are top-level predators in freshwater ecosystems.Mendoza Alfaro, R., González, C. A. and Ferrara, A. M. (2008), Gar biology and culture: status and prospects. Aquaculture Research, 39: 748–763. doi:10.1111/j.1365-2109.2008.01927.x Adults feed on freshwater fishes and birds. Young are prey to the introduced

largemouth bass The largemouth bass (''Micropterus salmoides'') is a carnivorous freshwater gamefish in the Centrarchidae ( sunfish) family, a species of black bass native to the eastern and central United States, southeastern Canada and northern Mexico, but ...

''(Micropterus salmoides)''. As an animal with a high

trophic level The trophic level of an organism is the position it occupies in a food web. A food chain is a succession of organisms that eat other organisms and may, in turn, be eaten themselves. The trophic level of an organism is the number of steps it ...

, the gar has lost much of its population due to overfishing and habitat loss. Attempts to restore natural fish populations using them in aquaculture are currently in progress, but these ideas have yet to reach implementation. Cuban gar are currently under research for use in broodstocking, both due to the threatened status of gar species and due to the potentially valuable role of gar in reducing the pressure of fisheries on natural aquatic ecosystems.Mendoza R., Aguilera C., Rodríguez G. & Márquez G. (2000) Estrategias para la domesticación de especies en acuacultura: El catán (''Atractosteusspatula''). In: ''Redes Nacionales de Investigación en Acuacultura, Memorias de la V Reunion'' (ed. by Ramírez-FloresÁlvarez Torres & Torres-RodríguezY Mora-Cervantes), pp. 95–102. Instituto Nacional de Pesca-SEMARNAP, Distrito Federal, México. No implementation of Cuban gar broodstocking for ecological protection has yet occurred, however.

References

{{Taxonbar, from=Q1790887 Lepisosteidae Fish described in 1801 Freshwater fish of Cuba Fish of the Caribbean Endemic fauna of Cuba Apex predators