|Scientific Name:||Plesiobatis daviesi|
|Species Authority:||(Wallace, 1967)|
|Taxonomic Notes:||This species is distinct in shape from all other stingarees, resulting in its placement in the separate monospecific family, Plesiobatidae. There has never been a comparison of populations of this species, which needs to be undertaken to elucidate whether there is in fact more than one species.|
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor(s):||White, W.T., Kyne, P.M. & Holtzhausen, H.|
|Reviewer(s):||Walls, R.H.L. & Dulvy, N.K.|
|Facilitator/Compiler(s):||Kyne, P.M. & Walls, R.H.L.|
The Giant Stingaree (Plesiobatis daviesi) is demersal on the continental slope at depths of 275–680 m (and occasionally in shelf waters), with a sporadic and patchy range in the Indo-Pacific region. Biology is poorly known and research needs to elucidate the relationship between different populations. The Giant Stingaree is occasionally caught in local deepwater trawl and longline fisheries, is only landed in low numbers, and deepwater fishing is usually relatively restricted within most of its range. In Indonesia, only a small deepwater longline fishery operates between 300 and 600 m and the species is thus not taken in any great quantities compared to other elasmobranch species. Similarly the deepwater fishery in Taiwan only catches low numbers of this species. In Australian waters, there is minimal fishing pressure on the species' range off Western Australia and Queensland. It is assessed as Least Concern due to the limited number and effort of fisheries presently operating throughout much of its range. However, the large size of this species and low number of records indicate low productivity, hence poor resilience to fisheries, and possible rarity. Future expansion of deepwater fisheries within its range could pose a threat, at which time this assessment would need revisiting.
|Previously published Red List assessments:||
|Range Description:||The Giant Stingaree has a sporadic range in the Indo-Pacific region, including southern Africa, India, Indonesia, eastern and western Australia, South China Sea, the Philippines, Japan, New Caledonia and Hawaii (Compagno and Last 1999, Last and Stevens 2009).|
Native:Australia (New South Wales, Queensland, Western Australia); China; India; Indonesia; Japan; Mozambique; New Caledonia; Philippines; South Africa (KwaZulu-Natal); United States (Hawaiian Is.)
|FAO Marine Fishing Areas:||
Indian Ocean – eastern; Indian Ocean – western; Pacific – southwest; Pacific – northwest; Pacific – western central; Pacific – eastern central
|Lower depth limit (metres):||680|
|Upper depth limit (metres):||44|
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||The Giant Stingaree has been reported to be locally common (Compagno and Last 1999), which may be the case off tropical Australia, however the generally low numbers of records elsewhere may indicate rarity.|
|Current Population Trend:||Unknown|
|Habitat and Ecology:||The largest and most widespread stingaree that lives in deeper water than any of its relatives in the family Urolophidae (Last and Stevens 2009). An upper continental slope species on soft substrates, generally at depths of 275–680 m (350–680 m in Australia), however there is a single record from 44 m on the continental shelf off Mozambique (Last and Stevens 1994, 2009, Compagno and Last 1999).
Like most other deepwater batoids, its biology is poorly known. It is probably viviparous but details of reproduction are unknown. Its large size and deepwater occurrence suggest a probable small litter size and long gestation period, resulting in a slow life history (L.J.V. Compagno, pers. comm.). Ebert et al. (2002) report a juvenile female at 189 cm TL and an adolescent female at 201 cm TL (116 cm disc width; DW). Males mature at 130-172 cm TL (Last and Stevens 2009). Maximum size at least 200 cm TL in Australia and elsewhere reported to 270 cm TL (Last and Stevens 2009). Consistent with geographic variability in maximum size, size at maturity probably also varies regionally. Size at birth is unknown, however Compagno and Last (1999) report that a 50 cm TL free living individual had an umbilical scar.
|Use and Trade:||There is no information on the potential use or trade of this species.|
While available specific data are lacking, the species is known to be taken in deepwater benthic trawls and on deepset longlines. It is not known to be targeted and not known to be taken in any considerable numbers in any one region within its range, although it can be taken regularly by longliners off KwaZulu-Natal (L.J.V. Compagno, pers. comm.). In Indonesia, only a small deepwater longline fishery operates between 300–600 m depth and the species is thus not taken in any great quantities compared to other elasmobranch species (W. White, pers. obs). Similarly the deepwater fishery in Taiwan only catches low numbers of this stingray (D. Ebert, pers. comm.).
In Australian waters, there is minimal fishing pressure within its range off Western Australia and Queensland. Off Western Australia, the Commonwealth managed Western Deepwater Trawl Fishery and Northwest Slope Trawl Fishery have only a small number of active vessels and low levels of effort (over a wide geographical area) (Marton and Mazur 2014a, 2014b), while off Queensland, the Commonwealth managed Coral Sea Fishery is a small-scale fishery with a demersal line sector and a trawl sector, but effort is low with no trawl effort since the 2006-07 fishing season (Noriega et al. 2014).
|Conservation Actions:||There are no species-specific conservation measures currently in place. Further information is required from catches of this species in order to better define its range and obtain life history data. Bycatch in globally expanding deepwater fisheries needs to be documented and monitored.|
|Citation:||White, W.T., Kyne, P.M. & Holtzhausen, H. 2015. Plesiobatis daviesi. The IUCN Red List of Threatened Species 2015: e.T60111A68640813. . Downloaded on 08 February 2016.|
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