Geographic Range
Convict tangs are found throughout the Indo-Pacific region, as well as the eastern
Pacific Ocean from the lower Gulf of California to Panama. They are also known as
convict surgeonfish or Manini.
- Biogeographic Regions
- indian ocean
- pacific ocean
Habitat
Convict tangs are surgeonfish that prefer to occupy coral reefs, but are also found
in tidepools and other nearshore habitats such as shallow, low current beach communities.
They are tropical reef fish whose latitudinal range is 26ºN to 36ºS with a longitudinal
range from 25ºE to 85ºW. Convict tangs are mainly found in temperatures ranging from
24-26ºC and at depths of 0-90 m.
- Habitat Regions
- tropical
- saltwater or marine
Physical Description
Convict tangs have a pale body color varying from white/greenish-white to gray or
even yellow. This background is overlaid with distinct, vertical black stripes, including
one going through each eye. They are highly laterally compressed and have small scales,
gill rakers, dorsal spines and anal spines. Their average length is 17.0 cm, with
a maximum length of 27.0 cm.
- Other Physical Features
- ectothermic
- bilateral symmetry
Development
Convict tang eggs hatch into clear pelagic larvae. In Hawaiian populations it takes
about 2.5 months for these planktonic larvae to develop into juveniles in a reef or
tidepool; larvae typically adapt to their benthic surroundings within 24 hours. Initially,
juveniles lack the vertical bars present in adults.
- Development - Life Cycle
- indeterminate growth
Reproduction
Convict tangs spawn in resident spawning aggregations. Spawning groups can be as large
as tens of thousands of fish with subgroups of 10-20 fish, although pair spawning
has also been observed. Research in Hawaii showed that individuals may migrate up
to 2 km to reach spawning sites on the seaward side of a reef or in channels connecting
lagoons to open ocean.
- Mating System
- polygynandrous (promiscuous)
Convict tang populations near the equator can spawn at any time during the year, while
populations elsewhere may only spawn seasonally (in Hawaii spawning occurs around
full moons in February and March).
- Key Reproductive Features
- iteroparous
- seasonal breeding
- year-round breeding
- gonochoric/gonochoristic/dioecious (sexes separate)
- sexual
- fertilization
- broadcast (group) spawning
- oviparous
Convict tangs are broadcast spawners and provide no parental investment to offspring.
- Parental Investment
- no parental involvement
Lifespan/Longevity
Convict tangs have a typical lifespan of 5-7 years in captivity. Their average lifespan
in the wild is currently unknown.
Behavior
Convict tangs are often found in schools (large and small) but may also be found individually.
While less territorial than other tangs, tank size is still an important consideration
for those keeping this species. Convict tangs have been observed in the wild exhibiting
tonic immobility (death feigning).
- Key Behaviors
- natatorial
- motile
- solitary
- territorial
- colonial
Home Range
There is currently no published information regarding the home range or territory size of Convict tangs.
Communication and Perception
Convict tangs are able to perceive their environments through a number of sensory
pathways, including sight, olfaction, sound and vibrations (detected by their lateral
lines). Information regarding which of these senses are important in intra- and interspecific
communication is currently unavailable.
- Perception Channels
- visual
- tactile
- acoustic
- vibrations
- chemical
Food Habits
Convict tangs are herbivores, grazing on algae found on rocks and corals. Adaptations
to their algivorous diet include mouths that are slightly downwardly-directed and
flexible, comb-like teeth.
- Primary Diet
-
herbivore
- algivore
- Plant Foods
- algae
Predation
Convict tangs have been observed exhibiting tonic immobility, which may be a response
to the presence of a predator. As with other surgeonfishes, they have sharp blades
on either side of the tail; however, these blades are poorly developed in convict
tangs and not typically used for defense. Instead, this species relies on traveling
in large schools, as well as its disruptive color pattern, for protection. Although
undoubtedly not a complete list of predators, convict tangs are known to be preyed
upon by argus grouper, ash-colored conger eel, honeycomb grouper, cornet fish, and
black-tail snapper. Eagle rays are also known to feed on convict tang gametes during
spawning.
- Anti-predator Adaptations
- cryptic
Ecosystem Roles
The grazing of convict tangs on algae helps keep algal populations in check. Convict
tangs also host symbiotic unicellular organisms in their gut, including one of the
largest known bacterial species (
Epulopiscium fishelsoni
). Convict tangs are host to endoparasitic nematodes and trematodes, as well as at
least one ectoparasitic copepod species.
- Epulopiscium fishelsoni (Class Clostridia, Kingdom Bacteria)
- Spirocamallanus colei (Class Secernentea, Phylum Nematoda)
- Hysterolecitha acanthuri (Class Trematoda, Phylum Platyhelminthes)
- Caligus flexispina (Subclass Copepoda, Subphylum Crustacea)
Economic Importance for Humans: Positive
Convict tangs are part of the human diet in tropical regions. They are also sold
in the aquarium trade.
Economic Importance for Humans: Negative
There have been reports of humans suffering from ciguatera poisoning after consuming
convict tangs, although the species is generally considered safe to eat.
- Negative Impacts
- injures humans
Conservation Status
Convict tangs currently have no special conservation status.
Other Comments
Genetic studies on Polynesian populations of convict tangs indicate that, despite
the pelagic larval stage, most populations exhibit limited recruitment through dispersal.
The large bacterium
Epulopiscium fishelsoni
was first isolated from the gut of brown surgeonfish (
A. nigrofuscus
); similar morphotypes, collectively called "euplos", have since been found in other
surgeonfish species, including convict tangs. Euplo morphotypes found in convict tangs
are 20 times longer than they are wide, which is much longer and thinner than those
found in other species of surgeonfish.
Additional Links
Contributors
Rex Gamoke (author), Sierra College, Jennifer Skillen (editor), Sierra College, Jeremy Wright (editor), University of Michigan-Ann Arbor.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- Pacific Ocean
-
body of water between the southern ocean (above 60 degrees south latitude), Australia, Asia, and the western hemisphere. This is the world's largest ocean, covering about 28% of the world's surface.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- tropical
-
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
- saltwater or marine
-
mainly lives in oceans, seas, or other bodies of salt water.
- pelagic
-
An aquatic biome consisting of the open ocean, far from land, does not include sea bottom (benthic zone).
- benthic
-
Referring to an animal that lives on or near the bottom of a body of water. Also an aquatic biome consisting of the ocean bottom below the pelagic and coastal zones. Bottom habitats in the very deepest oceans (below 9000 m) are sometimes referred to as the abyssal zone. see also oceanic vent.
- reef
-
structure produced by the calcium carbonate skeletons of coral polyps (Class Anthozoa). Coral reefs are found in warm, shallow oceans with low nutrient availability. They form the basis for rich communities of other invertebrates, plants, fish, and protists. The polyps live only on the reef surface. Because they depend on symbiotic photosynthetic algae, zooxanthellae, they cannot live where light does not penetrate.
- coastal
-
the nearshore aquatic habitats near a coast, or shoreline.
- ectothermic
-
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
- 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.
- indeterminate growth
-
Animals with indeterminate growth continue to grow throughout their lives.
- polygynandrous
-
the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.
- 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).
- seasonal breeding
-
breeding is confined to a particular season
- year-round breeding
-
breeding takes place throughout the year
- sexual
-
reproduction that includes combining the genetic contribution of two individuals, a male and a female
- fertilization
-
union of egg and spermatozoan
- external fertilization
-
fertilization takes place outside the female's body
- oviparous
-
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
- natatorial
-
specialized for swimming
- motile
-
having the capacity to move from one place to another.
- solitary
-
lives alone
- territorial
-
defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement
- colonial
-
used loosely to describe any group of organisms living together or in close proximity to each other - for example nesting shorebirds that live in large colonies. More specifically refers to a group of organisms in which members act as specialized subunits (a continuous, modular society) - as in clonal organisms.
- visual
-
uses sight to communicate
- tactile
-
uses touch to communicate
- acoustic
-
uses sound to communicate
- vibrations
-
movements of a hard surface that are produced by animals as signals to others
- chemical
-
uses smells or other chemicals to communicate
- cryptic
-
having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.
- pet trade
-
the business of buying and selling animals for people to keep in their homes as pets.
- food
-
A substance that provides both nutrients and energy to a living thing.
- poisonous
-
an animal which has a substance capable of killing, injuring, or impairing other animals through its chemical action (for example, the skin of poison dart frogs).
- herbivore
-
An animal that eats mainly plants or parts of plants.
References
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