|Scientific Name:||Urolophus aurantiacus|
|Species Authority:||Müller & Henle, 1841|
|Taxonomic Notes:||A valid species with no known taxonomic complications.|
|Red List Category & Criteria:||Near Threatened ver 3.1|
|Assessor/s:||Last, P.R. & Marshall, L.J.|
|Reviewer/s:||Kyne, P.M., Fowler, S.L. & Compagno, L.J.V. (Shark Red List Authority)|
Recorded from Japan, Taiwan, Vietnam and possibly Korea, U. aurantiacus is found in rocky habitats and is documented from depths of 10 to 205 m. Distribution may be disjunct and is not well defined. This stingaree is generally only found in small numbers with a patchy occurrence in suitable habitat. Little is known of its biology, but like other urolophids, has limiting reproductive characteristics (such as low fecundity). As this species probably does not aggregate, and is found in rocky habitat, it is less susceptible to fishing pressure from trawling. However, its range overlaps with heavily fished areas where management and regulation is limited and where fishing pressure on the continental shelf from various gear types (gillnet, set net and longline) is often intense. As inshore resources are depleted, the trend of increasing pressure on deeper habitats will have negative effects on this species. Its occurrence in a region where pressure on the continental shelf is generally unregulated and intense, its patchy occurrence (making it susceptible to localised depletion) and its limited biological characteristics, warrants an assessment of Near Threatened. Catch documentation and monitoring is required to better define the level of threat on this species.
|Range Description:||Japan, Taiwan, Vietnam (Kuiter and Debelius 1997), and possibly Korea. Range is not well defined. Possibly disjunct. Sporadic distribution in Japan, only found in suitable habitat (i.e., rocky areas).|
Native:Japan; Taiwan, Province of China; Viet Nam
|FAO Marine Fishing Areas:||
Pacific – northwest
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||Common but not abundant. Only found in small numbers where it occurs.|
|Habitat and Ecology:||
Found in rocky habitat over the continental shelf. Kuiter and Debelius (1997) report that the species is found at depths of 10 to 200 m and Nakaya and Shirai (1992) report it at 155 to 205 m in the Okinawa trough off Japan. Biology is little known. Michael (1993) reports a litter size of up to four and a gestation period of about one year. Urolophids generally have low fecundity and a gestation period around or approaching a year, so Michael?s observations seem consistent with published reports (see White et al. 2001, White et al. 2002), although fecundity is probably generally lower (i.e., 1 to 2 pups/litter).
Life history parameters
Age at maturity (years): Unknown.
Size at maturity (total length cm): Unknown.
Longevity (years): Unknown.
Maximum size (total length): 40 cm TL (Michael 1993).
Size at birth: ~8 cm TL (Michael 1993).
Average reproductive age (years): Unknown.
Gestation time: ~12 months (Michael 1993).
Reproductive periodicity: Unknown.
Average annual fecundity or litter size: Up to 4 (Michael 1993) (probably generally less, i.e., 1 to 2).
Annual rate of population increase: Unknown.
Natural mortality: Unknown.
Its preference for rocky habitat limits its susceptibility to trawling, however gillnet, set net and longline fishing activities in parts of its range are likely to take this species as bycatch. No information is available on such bycatch. Longline fisheries in areas such as Taiwan often employ gear that would regularly take this species (similar sized demersal batoids taken on bottom set lines are a commonly marketed product). Fisheries in the Asian region are generally unmanaged and unregulated and pressure on the continental shelf is intense.
This species? occurrence in deeper water was shown by Nakaya and Shirai (1992) in the Okinawa Trough, south of Japan. Bycatch through any expansion of deepwater demersal fishing activities will likely increase pressure on deeper subpopulations in those areas.
Habitat alteration in inshore areas may indirectly impact the species.
Research into habitat requirements and life history together with bycatch and market monitoring, is necessary.
The development and implementation of management plans (national and/or regional e.g. under the FAO International Plan of Action for the Conservation and Management of Sharks: IPOA-Sharks) are required to facilitate the conservation and sustainable management of all chondrichthyan species in the region.
|Citation:||Last, P.R. & Marshall, L.J. 2006. Urolophus aurantiacus. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 11 December 2013.|
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