|Scientific Name:||Canthigaster jactator (Jenkins, 1901)|
Tropidichthys jactator Jenkins, 1901
|Taxonomic Notes:||The genus Canthigaster is hypothesized to undergo fast morphological/colour differentiation and slow mtDNA evolution (Randall et al. 2008).
Using a number of nuclear and mitochondrial markers, Alfaro et al. (2007) detected almost no difference between the Hawaiian C. jactator and the Indo-Pacific C. janthinoptera.
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor(s):||Shao, K., Matsuura, K., Leis, J.L., Hardy, G., Jing, L. & Liu, M.|
|Facilitator/Compiler(s):||Carpenter, K.E., Comeros-Raynal, M., Harwell, H. & Sanciangco, J.|
Canthigaster jactator is endemic to the Hawaiian Islands and Johnston Atoll, where it is common and locally abundant. Canthigaster jactaror is a reef-associated species, which can be found in a variety of habitats at depths ranging from 1–89 metres. It is an opportunistic generalist, feeding on a variety of vertebrate and invertebrate prey. Canthigaster jactator is a component of the marine aquarium trade, however there are no indications of population declines from harvesting at present time. There have been no documented population declines in C. jactator. There are no species-specific conservation measures in place for C. jactator, however its distribution overlaps with several marine reserves in parts of its range. It is therefore listed as Least Concern. We recommend monitoring of harvest levels for the aquarium trade.
|Range Description:||Canthigaster jactator is endemic to the Hawaiian Islands and Johnston Atoll (Randall 1996). It is found at depths ranging from 1–89 metres.|
Native:United States (Hawaiian Is.); United States Minor Outlying Islands (Johnston I.)
|FAO Marine Fishing Areas:|
Pacific – eastern central; Pacific – northwest
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||Canthigaster jactator is the most abundant species in its family in Hawaii (Hourigan and Reese 1987). In a study of black coral communities and their associated deep-water communities in Maui, Hawaii, C. jactator was routinely observed to use deep-water black coral patches (Antipathes spp.) during the day and was among the top 20 most frequently-sighted fish species (Boland and Parrish 2005). Thirty by four metre transect surveys (120 m2) in Hawaii showed this species to occur at densities of 3.8–4.5 fish per transect (Reavis and Barrett 2001).|
Specimens of C. jactator are very common in museum collections (FishNet2 searched 28 March 2012).
Due to its affinity with coral reefs, C. jactator may be experiencing population declines due to habitat loss in parts of its range.
|Current Population Trend:||Unknown|
|Habitat and Ecology:||Canthigaster jactator is a diurnal species which is commonly found on lagoon and seaward reefs (Lieske and Myers 1994) over coral, rock, rubble, and sand at depths ranging from 1–89 metres (Mundy 2005). This species can be found within man-made harbours and near other artificial structures and is thought to be an opportunistic species with generalist habitat requirements (Brock 1981). It feeds on sponges, algae, detritus, tunicates, polychaetes, bryozoans, sea urchins, brittle stars, crabs, peanut worms, shrimps, zooanthids, fishes, amphipods and foraminiferans (Randall 1985). This species is also known to be a carnivorous cleaner of the green sea turtle, Chelonia mydas (Zamzow 2000). Canthigaster jactator is coated in a protective mucous which renders it black when seen at with a 340 nm filter (Zamzow and Losey 2002). A Philometra sp. nematode is known to infect the abdominal cavity of this species in Hawaii, causing severe abdominal bloating (Deardorff and Stanton 1983) and delaying or inhibiting sexual maturation (Reavis and Barrett 2001). This species is a routine diurnal user of deepwater black-coral patches (Antipathes spp.) in Hawaii and remained within one meter of the coral, using it for cover in transit though not residing on a particular coral tree (Boland and Parrish 2005).|
There is no information on the spawning or social structure of C. jactator available. However, spawning, sexual dimorphism, and social structure have been observed in the field in other species of Canthigaster. In all species for which spawning has been described, males are larger than females and defend territories that include multiple females. Spawning occurs during the day and involves the preparation of an algal nest on the substratum by the females into which eggs are deposited and fertilized by the male, and spawning occurs in multiple bouts, with no parental care after the last bout. This is consistent with field observations of spawning, social organization, and sexual dimorphism in other Canthigaster species (Gladstone 1987, Kobayashi 1988, Sikkel 1990, Sikkel and Sikkel 2012).
Canthigaster spp. are known for their general lack of characters, and are generally differentiated on the basis of colour differences.
|Use and Trade:||
Canthigaster jactator is collected and exported from Hawaii for the aquarium trade. From 1967–2003, 69,869 individuals, valuing $66,760.97 USD, were collected (Walsh et al. 2003).
Canthigaster jactator is a component of the marine aquarium trade, however there are no data at present indicating declines from harvesting.
There have been no confirmed population declines in C. jactator. However, because of its affinity with coral reefs, we infer that C. jactator may be experiencing population declines due to habitat loss in parts of its range.
As of 2008, fifteen percent of the world’s coral reefs were considered under imminent threat of being “Effectively Lost” (with 90% of the corals lost and unlikely to recover soon), with regions in East Africa, South and South-east Asia, and the wider Caribbean being the most highly threatened (Wilkinson et al. 2008).
Of 704 zooxanthellate reef-building coral species which were assessed by using the International Union for Conservation of Nature Red List Criteria, 32.8% are in categories with elevated risk of extinction (Carpenter et al. 2008).
There are no known species-specific conservation measures in place for C. jactator, however its distribution overlaps with several marine protected areas.
|Citation:||Shao, K., Matsuura, K., Leis, J.L., Hardy, G., Jing, L. & Liu, M. 2014. Canthigaster jactator. The IUCN Red List of Threatened Species 2014: e.T193663A2256343.Downloaded on 21 November 2017.|
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