Hemiscyllium ocellatum (New Guinea subpopulation)
|Scientific Name:||Hemiscyllium ocellatum (New Guinea subpopulation)|
|Red List Category & Criteria:||Near Threatened ver 3.1|
|Assessor(s):||Bennett, M.B. & Kyne, P.M. (SSG Australia & Oceania Regional Workshop, March 2003)|
|Reviewer(s):||Cavanagh, R.D. & Fowler, S.L. (Shark Red List Authority)|
In New Guinea Hemiscyllium ocellatum may be collected as part of a subsistence/artisanal fishery and severe degradation of its habitat occurs in parts of its range through destructive fishing practices and high pollutant loads. The species is listed as Least Concern globally, but Near Threatened (due to concern that it could meet the criterion A3cde for Vulnerable) around New Guinea, reflecting the pressures facing the species in that region.
|Range Description:||Assessment limited to the New Guinea subppulation only.|
Native:Indonesia (Papua); Papua New Guinea
|FAO Marine Fishing Areas:|
Pacific – western central
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||The population size and details of the range of this subpopulation are unknown.|
|Current Population Trend:||Unknown|
|Habitat and Ecology:||A small, slender shark of up to about 1 m total length (TL). At Heron Island Reef, Queensland, individuals did not exceed 76 cm TL and a mass of 900 g (n = 497). A species that is commonly encountered in shallow coral reef waters. It is well camouflaged and can been observed foraging over reef flats. Its activity pattern is affected by a combination of suitable tidal and light conditions: It is more active at low water and, although epaulette sharks can be found actively hunting during daylight hours, it is more active after dark and particularly around dawn or dusk. The diet comprises a variety of benthic organisms that it takes from the surface of the substrate or, by burying its head into the substrate, from a few centimetres below the surface (Heupel and Bennett 1998). Annelids and crabs account for the majority of the diet in this species, although there is a degree of ontogenetic shift in dietary preference, with shrimps becoming a more important part of the adult diet (Heupel and Bennett 1998). At rest sharks commonly hide in or beneath coral heads. If in the open, they orient themselves with their head into the oncoming water stream, presumably for station-holding and possibly for prey/threat detection (Peach 2002).
An oviparous species with males and females maturing at 54 to 62 cm TL. Mating probably occur between July and November, with females carrying eggcases found between August and December, although in captivity they have been noted to breed continuously (West and Carter 1990). Two egg capsules are produced and deposited among coral at night. A pair of egg capsules may be produced every 14 days, resulting in up to about 20 potential offspring per female per annum. Eggs hatch after about 120 days with young at 14 to 16 cm TL. Subsequent growth is initially slow, but reaches about five cm year-1 after about three months (West and Carter 1990). Epaulette sharks descend into deeper water between coral reefs and have been found at depths of at least 40 m. The species is hypoxia tolerant and is able to survive in anoxic waters. This trait is important as this shark is often found in shallow (ca 15 cm deep), warm (ca 30°C) waters that become severely hypoxic during the night. This trait may enable this species to survive in areas of poor water quality, such as mining run-off in New Guinea.
|Major Threat(s):||Around New Guinea the species is likely to be threatened by overfishing, destructive fishing practices and habitat modification, including the damage and destruction of coral reefs from dynamite fishing and pollution. These processes are likely causing declines in all hemiscyllid species occurring around New Guinea, however quantitative data are not available. The wider distribution of H. ocellatum compared with other endemic Hemiscyllium spp. and the fact that the species is abundant in Australian waters means the species is not threatened with extinction on a global basis. However, given the pressures facing all hemiscyllid sharks around New Guinea, the status of the species requires close monitoring.|
|Conservation Actions:||None needed at present.|
|Citation:||Bennett, M.B. & Kyne, P.M. (SSG Australia & Oceania Regional Workshop, March 2003). 2003. Hemiscyllium ocellatum (New Guinea subpopulation). The IUCN Red List of Threatened Species 2003: e.T42833A10757379.Downloaded on 12 December 2017.|
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