|Scientific Name:||Aptychotrema timorensis Last, 2004|
|Taxonomic Source(s):||Last, P.R., Séret, B. and Naylor, G.J.P. 2016a. A new species of guitarfish, Rhinobatos borneensis sp. nov. with a redefinition of the family-level classification in the order Rhinopristiformes (Chondrichthyes: Batoidea). Zootaxa 4117(4): 451-475.|
|Taxonomic Notes:||Previously listed as Aptychotrema sp. nov. A. This species has recently been described (Last 2004) and is a distinct member of the endemic East Indo-West Pacific genus Aptychotrema, of which there are three valid species in Australian waters.|
|Red List Category & Criteria:||Vulnerable B1ab(v) ver 3.1|
|Assessor(s):||Last, P.R., Kyne, P.M. & Sherman, C.S.|
|Reviewer(s):||Dulvy, N.K. & Lawson, J.|
|Facilitator/Compiler(s):||Kyne, P.M., Walls, R.H.L., Simpfendorfer, C. & Chin, A.|
The Spotted Shovelnose Ray (Aptychotrema timorensis) is presently known from only a few specimens. One specimen was taken from the continental shelf at 124 m in the Timor Sea, at the edge of the Australian Fishing Zone (adjacent to Indonesian waters). Additional specimens recently located in a Taiwanese collection are presumably from northern Australia, where Taiwanese trawlers used to operate.
The population size is suspected to be very small as considerable survey work has failed to find other specimens. About 650 large Thai pair trawlers from the port of Merauke in West Papua operate in the Arafura Sea, which lies adjacent to the Timor Sea. This fishery is unregulated and batoids compose a substantial portion of the catch, all of which is retained and marketed. Although the impact of fishing on this species is unknown, the potential area of occurrence of the Spotted Shovelnose Ray faces unregulated fishing and this is of particular concern due to its apparent rarity, inferred small population size and limited distribution.
While there is considerable uncertainty concerning the status of this species, a Vulnerable assessment is warranted due to an estimated extent of occurrence (EOO) of <20,000 km², occurrence in <10 locations, and an inferred continuing decline in the number of mature individuals. Continuing decline in this population is inferred, given that batoids make up a significant proportion of the catch in unregulated fisheries in Indonesian waters where this species may occur. It is even possible that steep declines may have occurred already for this species as there have only been a few specimens encountered despite extensive survey work throughout their range. Further information may result in a lower category being more appropriate. Conversely, an increase in fishing pressure would likely drive the species into a higher category.
|Previously published Red List assessments:|
|Range Description:||As currently known, the Spotted Shovelnose Ray is restricted to a small area of the Timor Sea off northern Australia (Last and Stevens 2009). It is presumed to be restricted to the east of its presently known location as ridges would impede the movement of the species to the west. Originally known from only one specimen from the Timor Sea, some additional specimens (presumably originating from northern Australia, but exact location unknown) have been located in the National Museum of Marine Biology and Aquarium (NMMBP) collection in Taiwan (W.T. White, CSIRO. pers. comm., February 2015). Its estimated extent of occurrence (EOO) is ~18,000 km², and this species is likely to be patchy throughout this range, rather than be evenly distributed. The number of locations is unknown, but is inferred to be <10.|
Native:Australia (Northern Territory)
|FAO Marine Fishing Areas:|
Pacific – western central
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||The Spotted Shovelnose Ray is known only from a few specimens. Population size is suspected to be very small as considerable survey work has failed to find any other specimens.|
|Current Population Trend:||Unknown|
|Habitat and Ecology:||The type specimen of the Spotted Shovelnose Ray, a 58.2 cm total length (TL) female, was recorded from the continental shelf at 124 m depth. Nothing is known of the life history characteristics of the species, although it is presumably lecithotrophic viviparous like other members of the genus. Recorded litter sizes of congeneric species are 14-16 for the Western Shovelnose Ray (A. vincentiana) (Haake 1885) and 4-18 for the Eastern Shovelnose Ray (A. rostrata) (Kyne and Bennett 2002).|
|Use and Trade:||No information is available on potential use due to the rarity of the species. In Indonesia, guitarfishes are retained for meat and fins (although dorsal fins are small in Aptychotrema species due to their small size) so if the species is taken by Indonesian vessels then it would be retained for meat.|
The potential extent of occurrence of this species faces unregulated fishing and this is of particular concern due to its apparent rarity, inferred small population size and limited distribution.
A single specimen of known origin was collected near the edge of the Australian Fishing Zone. The remaining specimens held in the NMMBA collection are of unknown origin, presumably from northern Australia (W. White, pers. comm., February 2015). The species may therefore enter the bycatch of northern Australian prawn trawl fisheries, but this is likely to be negligible based on the depth at which the type specimen was taken (124 m). The area adjacent to the Australian Fishing Zone in Indonesian waters is entirely unmanaged, with fishing vessels operating out of eastern Indonesia and there appears to be more activity in this area than was previously thought. About 650 large Thai pair trawlers operate in the Arafura Sea from the port of Merauke in West Papua. This fishery is unregulated and batoids compose a substantial portion of the catch, all of which is retained and marketed. Batoids are heavily fished in Indonesia, with catches and effort increasing (see White and Dharmadi 2007). Pressure on any Indonesian portion of the range of the Spotted Shovelnose Ray would be intense through these unregulated fisheries.
|Conservation Actions:||Currently, there are no direct conservation actions in place for this species. Surveys in the Timor and Arafura Seas need to be continued in order to record any future records of the species, and therefore, better document the species' distribution, to accurately determine its extent of occurrence and area of occupancy, and population size.|
Haacke, V.W. 1885. Über eine neue Art uterinalar Brutpflege bei Wirbelthieren. Zoologischer Anzeiger 8(202), 488–490.
IUCN. 2015. The IUCN Red List of Threatened Species. Version 2015-4. Available at: www.iucnredlist.org. (Accessed: 19 November 2015).
IUCN SSC Shark Specialist Group. Specialist Group website. Available at: http://www.iucnssg.org/.
Kyne, P.M. and Bennett, M.B. 2002. Reproductive biology of the eastern shovelnose ray, Aptychotrema rostrata (Shaw & Nodder, 1794), from Moreton Bay, Queensland, Australia. Marine and Freshwater Research 53:583–589.
Last, P.R. 2004. Rhinobatos sainsburyi n.sp. and Aptychotrema timorensis n.sp.-Two new shovelnose rays (Batoidea: Rhinobatidae) from the Eastern Indian Ocean. Records of the Australian Museum 56:201–208.
Last, P.R. and Stevens, J.D. 2009. Sharks and Rays of Australia. Second Edition. CSIRO Publishing, Collingwood.
White, W.T. and Dharmadi. 2007. Species and size compositions and reproductive biology of rays (Chondrichthyes, Batoidea) caught in target and non-target fisheries in eastern Indonesia. Journal of Fish Biology 70: 1809-1837.
|Citation:||Last, P.R., Kyne, P.M. & Sherman, C.S. 2015. Aptychotrema timorensis. The IUCN Red List of Threatened Species 2015: e.T60179A68609203.Downloaded on 20 October 2017.|
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