Rhina ancylostoma

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA CHONDRICHTHYES RAJIFORMES RHINIDAE

Scientific Name: Rhina ancylostoma
Species Authority: Bloch & Schneider, 1801
Common Name(s):
English Bowmouth Guitarfish, Mud Skate, Shark Ray

Assessment Information [top]

Red List Category & Criteria: Vulnerable A2bd+3bd+4bd ver 3.1
Year Published: 2003
Date Assessed: 2003-04-30
Annotations:
Needs updating
Assessor(s): McAuley, R. & Compagno, L.J.V. (SSG Australia & Oceania Regional Workshop, March 2003)
Reviewer(s): Fowler, S., Kyne, P.M. & Cavanagh, R.D. (Shark Red List Authority)
Justification:
Rhina ancylostoma is a widely distributed Indo-west Pacific inshore species taken by multiple artisanal and commercial fisheries throughout its range both as a target species and as bycatch. Flesh is sold for human consumption in Asia and the fins from large animals fetch exceptionally high prices, creating a significant incentive for bycatch to be retained. Very little is known about the biology or population status of this species, but it appears not to be common anywhere. Given its susceptibility to capture by multiple fishing gear types, including trawl nets, gillnets and hooks, and its high value fins, it is probable that numbers have been locally reduced by fishing throughout its range. Local population depletion can be inferred from Indonesia where the target gillnet fishery fleet for rhinids and rhynchobatids has declined significantly, reportedly due to declining catch rates. It is probable that the population will continue to decline, at least, until target fisheries become uneconomical. Habitat destruction is also thought to pose a significant threat to R. anclyostoma throughout much of its range. Thus, given its susceptibility to capture, high value fins, inferred and observed declines, and continual fisheries pressure placed across most of its range the species is assessed globally as Vulnerable.

There are no target fisheries for R. ancylostoma in Australia but it is a known bycatch of demersal trawl fisheries. The introduction of Turtle Exclusion Devices (TEDs) in some Australian trawl fisheries and the implementation of various elasmobranch-finning prohibitions, has probably led to a recent reduction in captures by this sector, hence the Near Threatened classification for this species in Australian waters, although the situation should be monitored due to the vulnerability of this species and the high value of its fins.

Geographic Range [top]

Range Description:Indo-west Pacific: East Africa (Red Sea to South Africa) to Papua New Guinea, north to Japan, across northern Australia from Exmouth Gulf in Western Australia to New South Wales.
Countries:
Native:
Australia (New South Wales, Northern Territory, Queensland, Western Australia); Bahrain; China; Djibouti; Egypt; Eritrea; India; Indonesia (Jawa, Kalimantan); Iran, Islamic Republic of; Japan; Kenya; Korea, Democratic People's Republic of; Korea, Republic of; Kuwait; Malaysia; Mozambique; Oman; Pakistan; Papua New Guinea; Philippines; Qatar; Saudi Arabia; Seychelles; Solomon Islands; Somalia; South Africa (KwaZulu-Natal); Sri Lanka; Sudan; Taiwan, Province of China; Tanzania, United Republic of; Thailand; United Arab Emirates; Viet Nam; Yemen
FAO Marine Fishing Areas:
Native:
Indian Ocean – eastern; Indian Ocean – western; Pacific – northwest; Pacific – southwest; Pacific – western central
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population: The R. ancylostoma population is thought to have decreased in parts of Indonesia (Chen 1996) but its population status elsewhere is unclear.
Population Trend: Decreasing

Habitat and Ecology [top]

Habitat and Ecology: Coastal distribution throughout the range, generally occurring close inshore and around coral reefs to about 90 m (Anonymous 2003). R. ancylostoma occurs on or close to the seabed, mainly over sandy or muddy substrates. Very little is known about the life history characteristics of this species, however, they grow to at least 270 cm (Compagno and Last 1999), reproduce ovoviviparously and feed primarily on benthic crustaceans (Compagno and Last 1999). Further research on the biology and exploitation of this species is required.
Systems: Marine

Threats [top]

Major Threat(s): Rhina anclyostoma is one of the target species of South East Asian rhinid and rhynchobatid gillnet fisheries (W. White, pers. comm.), which are generally unregulated and catches are thought to be poorly recorded (Chen 1996). The target gillnet fishery fleet in Indonesia declined from 500 boats in 1987 to 100 boats in 1996, reportedly due to declining catch rates (Chen 1996). There are no target fisheries for this species in Australia. It is also taken as bycatch in numerous non-target fisheries due to its vulnerability to multiple gear types, including trawl-nets, gillnets and hooks (Stobutzki et al. 2002, Stephenson and Chidlow in prep., McAuley unpublished data). Flesh is sold for human consumption in Asia and the fins from large animals fetch particularly high prices. Habitat degradation is also likely to be a threat to this species, particularly in Southern and South East Asia.

Habitat destruction and pollution are thought to pose a significant threat. Specifically, dynamite fishing, coral bleaching and siltation caused by deforestation may be reducing available habitat.

Conservation Actions [top]

Conservation Actions: The introduction of Turtle Excluder Devices (TEDs) in trawl nets of some Australian fisheries, has significantly reduced their capture of large elasmobranchs (Brewer et al. 1998), however TEDs are not mandatory in several trawl fisheries in northern Australian and are probably not widely used in other parts of this species? range. The introduction of TEDs in other Australian trawl fisheries is highly recommended for mitigating bycatch of this and other at risk elasmobranchs.

Finning of Rhynchobatids is also prohibited in some parts of Australia but there is thought be a continuing black market trade in their fins (Rose and McLoughlin 2000, McAuley unpublished data).

Bibliography [top]

Anonymous. 2003. Rhina ancylostoma Bowmouth Guitarfish. Fishbase.

Brewer, D.T., Rawlinson, N., Eayrs, S. and Burrige, C. 1998. An assessment of bycatch reduction devices in a tropical Australian prawn trawl fishery. Fish Research 36: 195-215

Chen, H.K. (ed.) 1996. An overview of shark trade in selected countries of Southeast Asia. TRAFFIC Southeast Asia, Petaling Jaya.

Compagno, L.J.V. and Last, P.R. 1999. Rhinidae. In: K.E. Carpenter and V.H.Niem (eds) FAO species identification guide for fishery purposes. The living marine resources of the Western Central Pacific. Volume 3. Batoid fishes, chimaeras and bony fishes part 1 (Elopidae to Linophyrnidae), pp. 1418-1422. FAO, Rome.

IUCN. 2003. 2003 IUCN Red List of Threatened Species. www.iucnredlist.org. Downloaded on 18 November 2003.

IUCN SSC Shark Specialist Group. Specialist Group website. Available at: http://www.iucnssg.org/.

Last, P.R. and Stevens, J.D. 1994. Sharks and Rays of Australia. CSIRO, Australia.

Rose, C. and McLoughlin, K. 2001. Review of Shark Finning in Australian Fisheries. Final Report to the Fisheries Resources Research Fund. Bureau of Rural Sciences, Canberra

Stevenson, P and Chidlow, J.A. In prep. By-catch in the Pilbara Trawl Fishery. Draft report to Environment Australia. Department of Fisheries, Perth, WA.

Stobutzki, I.C., Miller, M.J., Heales, D.S. and Brewer, D.T. 2002. Sustainability of elasmobranches caught as bycatch in a tropical prawn (shrimp) trawl fishery. Fishery Bulletin 100: 800-821.


Citation: McAuley, R. & Compagno, L.J.V. (SSG Australia & Oceania Regional Workshop, March 2003) 2003. Rhina ancylostoma. In: The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 23 July 2014.
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