Osteoglossum bicirrhosumArawana

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Geographic Range

Osteoglossum bicirrhosum are native to the Amazon drainage system, the western Orinoco and the Rupununi and Essequibo systems of the Guianas. When found in other locations it is because of introduction by man. For example, they have been introduced in secluded areas of California and Nevada. It is also thought that the fish have not distributed themselves further up river because they cannot pass through rapids successfully. (Goulding, 1980; Nico, July 18, 2000)

Habitat

Osteoglossum bicirrhosum live in both the white and black water floodplains of the Amazon as documented in a recent study of the fish communities. In both types of water they were most abundant in the flooded/swamp areas. Osteoglossum bicirrhosum are usually found in the shallower of these waters because of their predatory behavior. (Goulding, 1980; Saint-Paul, et al., March 2000)

  • Aquatic Biomes
  • rivers and streams

Physical Description

Osteoglossum bicirrhosum are characterized by remarkable scale arrangements in which the scales are large, stout, bony and ornamented in a way that the radii form a course pattern. The scales are a pearly silver in color and change to reds, blues and greens as the fish ages. They are also well known for their bony tongue, after which it is named. Osteoglossum bicirrhosum are laterally compressed with a huge oblique mouth. Many oral bones bear teeth, including the jaw, palate, tongue and pharynx. They reach a maximum length of about 120 cm. (Goulding, 1980; Nico, July 18, 2000)

  • Average mass
    4600 g
    162.11 oz
  • Average mass
    2530 g
    89.16 oz
    AnAge
  • Range length
    120 (high) cm
    47.24 (high) in

Reproduction

Osteoglossum bicirrhosum spawn at the beginning of the floods, December and January. The females produce a rather small number of large eggs. The males carry the eggs, larvae and early juveniles in their mouths until the yolk sac has been absorbed, which is about 2 months. (Froese, March 7, 2000; Goulding, 1980)

  • Breeding interval
    These fish breed once a year.
  • Breeding season
    Osteoglossum bicirrhosum spawn at the beginning of the floods, December and January

Lifespan/Longevity

  • Average lifespan
    Status: captivity
    6.5 years
    AnAge

Behavior

Osteoglossum bicirrhosum have a unique predatory behavior. They stay close to shore and wait for prey to swim by. They usually keep lateral with a downed tree, to hide. Then they attack their prey, which usually involves jumping out of the water, to either catch large insects, other fish, or small birds in low hanging branches. This behavior has earned the fish the nickname "water-monkey" (Goulding 1980).

Communication and Perception

Food Habits

Osteoglossum bicirrhosum are not picky eaters. In a study of their stomach contents, the majority of food items included insects and spiders, most of which were beetles. Also found in the stomachs were crabs, snails, fish, birds, snakes, monkey feces and plant material. It is thought that the snakes and monkey feces were consumed during a flooding. The plant material was probably a result of the predatory behavior of the fish, as explained below (Goulding 1980).

Economic Importance for Humans: Positive

Osteoglossum bicirrhosum are of great economic value to the local fisherman. According to Junk (1976) these fish provide the largest source of protein in comparison to other Amazon fish. Also, because of its low fat content, they are considered the most digestable and least likely to bring about sickness. Osteoglossum bicirrhosum are also of great value in the aquarium business, as noted by the sale of them on many commercial internet sites (Foeshe 2000, Smith 1981).

Economic Importance for Humans: Negative

Unknown

Conservation Status

Other Comments

Osteoglossum bicirrhosum is thought by the Caboclo people of the Amazon to be very beneficial to women after they have recently given birth. In fact, they are one of the few things women are allowed to eat during this vulnerable point in life (Goulding 1980).

Contributors

William Fink (editor), University of Michigan-Ann Arbor.

Kelly Birchmeier (author), University of Michigan-Ann Arbor.

Glossary

Neotropical

living in the southern part of the New World. In other words, Central and South America.

World Map

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

external fertilization

fertilization takes place outside the female's body

fertilization

union of egg and spermatozoan

freshwater

mainly lives in water that is not salty.

heterothermic

having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

natatorial

specialized for swimming

native range

the area in which the animal is naturally found, the region in which it is endemic.

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

tactile

uses touch to communicate

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

References

Froese, R. March 7, 2000. "Species Summary for Osteoglossum bicirrhosum" (On-line). Accessed October 25, 2000 at http://www.fishbase.org/Summary/SpeciesSummary.cfm?ID=6234.

Goulding, M. 1980. The Fishes and The Forest. Los Angeles: University of California Press.

Nico, L. July 18, 2000. "Nonindigenous Aquatic Species: Osteoglossum bicirrhosum" (On-line). Accessed October 19, 2000 at http://nas.er.usgs.gov/fishes/accounts/osteoglo/os_bicir.html.

Saint-Paul, U., J. Zuanon, M. Villacorta, M. Garcia, F. Noemi. March 2000. Fish communities in central Amazonian white- and blackwater floodplains. Environmental Biology of Fishes, 57(3): 235-250.

Smith, N. 1981. Man, Fishes, and The Amazon. New York: Columbia University Press.