Rhina ancylostoma 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Chondrichthyes Rhinopristiformes Rhinidae

Scientific Name: Rhina ancylostoma Bloch & Schneider, 1801
Common Name(s):
English Bowmouth Guitarfish, Mud Skate, Shark Ray
Taxonomic Source(s): Bloch, M.E. and Schneider, J.G. 1801. M.E. Blochii, Systema Ichthyologiae iconibus cx illustratum. Post obitum auctoris opus inchoatum absolvit, correxit, interpolavit Jo. Gottlob Schneider, Saxo. Berolini. Sumtibus Austoris Impressum et Bibliopolio Sanderiano Commissum, Berolini.

Assessment Information [top]

Red List Category & Criteria: Vulnerable A2bd+3bd+4bd ver 3.1
Year Published: 2016
Date Assessed: 2015-02-20
Assessor(s): McAuley, R.B., Compagno, L.J.V. & Chin, A.
Reviewer(s): Simpfendorfer, C. & Dulvy, N.K.
Facilitator/Compiler(s): Kyne, P.M., Walls, R.H.L., Simpfendorfer, C. & Chin, A.
The Shark Ray (Rhina ancylostoma) is a widely distributed inshore species of the Indo-West Pacific. This species is 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. Estimated generation length (7.5 years) is moderate but this is based on proxy data and needs to be verified. Given its susceptibility to capture by multiple fishing gear types, including trawl nets, gillnets and hooks, and its high value fins, it is inferred 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 (>50% over 3 generations). 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 the Shark Ray throughout much of its range.

Based on its shallow water habitat preferences, its susceptibility to capture, high value fins, continual fisheries pressure placed across most of its range, global declines in chondrichthyan landings of at least 20% over the past 12 years, and the fact that the Indo-West Pacific is a region with some of the most poorly managed and intensely fished waters, a population reduction of greater than 30% over three generations is inferred for the Shark Ray, resulting in an assessment of Vulnerable.

In Australian waters, this species is classified as Near Threatened (close to meeting VU A2c+A3c). There are no target fisheries for the Shark Ray in Australia but it is a known bycatch species in demersal trawl fisheries. The introduction of turtle exclusion devices (TEDs) in Australian trawl fisheries and the implementation of various elasmobranch-finning prohibitions has probably led to a recent reduction in captures by this sector. However, the lack of information about the species, suspected longevity and low reproductive rate, and high economic value support an assessment of Near Threatened, and the situation should be monitored due to the suspected vulnerability of this species and the high value of its fins.
Previously published Red List assessments:

Geographic Range [top]

Range Description:The Shark Ray is wide-ranging in the Indo-West Pacific from East Africa (Red Sea to South Africa) to Papua New Guinea, north to Japan, across northern Australia from Shark Bay in Western Australia to Sydney in New South Wales, and east to New Caledonia (Last and Stevens 2009, Fricke et al. 2011).
Countries occurrence:
Australia (New South Wales, Northern Territory, Queensland, Western Australia); Bahrain; Bangladesh; China; Djibouti; Egypt; Eritrea; India; Indonesia (Jawa, Kalimantan); Iran, Islamic Republic of; Japan; Kenya; Korea, Democratic People's Republic of; Korea, Republic of; Kuwait; Madagascar; Malaysia; Mozambique; New Caledonia; 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:
Indian Ocean – eastern; Indian Ocean – western; Pacific – northwest; Pacific – western central; Pacific – southwest
Additional data:
Lower depth limit (metres):90
Range Map:Click here to open the map viewer and explore range.

Population [top]


Globally, shark and ray landings have declined by at least 20% since 2003, but the Indo-Pacific is amongst the regions where this decline has been more severe (Dulvy et al. 2014). Catches of sharks and rays in Southeast Asia are very high but are declining and fishers are travelling much further from port in order to increase catches (Chen 1996). Net and trawl fisheries in Indonesia (especially the Java Sea) and elsewhere are very extensive and as a result, many shark and ray species are highly exploited and stocks of most species have declined by at least an order of magnitude (Blaber et al. 2009). Batoids are heavily exploited (White and Dharmadi 2007) and datasets from as early as 1963–1972 show the considerable decline in batoids in the Gulf of Thailand (Pauly 1979). Trawl and gill net fisheries are also moving further afield. For example, in Jakarta the gillnet fishery at Muara Baru travels to waters around Kalimantan due to the decline in local populations (W.T. White, unpubl. data). While species-specific data on long-term declines in elasmobranchs in the Southeast Asian region are lacking, declines of the Shark Ray in Southeast Asia and elsewhere in the Indo-West Pacific are inferred given the widespread historical and continuing declines of demersal fisheries in this region (Stobutzki et al. 2006). Furthermore, the extensive loss and degradation of habitats such as coastal mangroves are another key threat to coastal and inshore species; Southeast Asia has seen an estimated 30% reduction in mangrove area since 1980 (FAO 2007, Polidoro et al. 2010).

Current Population Trend:Decreasing
Additional data:

Habitat and Ecology [top]

Habitat and Ecology:The Shark Ray has a coastal distribution throughout its range, generally occurring close inshore and around coral reefs to about 90 m (Anonymous 2003, Fricke et al. 2011). It 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, it is a large species growing to at least 270 cm total length (TL) and is lecithotrophic viviparous (Compagno and Last 1999). Males mature between 150 and 175 cm TL, and one pregnant female was recorded with 9 mid-term embryos ranging between 27-31 cm TL (Last and Stevens 2009). A single new born individual of 51 cm TL has been observed (Last et al. 2010). Further research on the biology, life history and exploitation of this species is needed.

Generation length is unknown. The Giant Shovelnose Ray (Glaucostegus typus) grows to a similar size and is a related species and using it as a proxy species, generation length is estimated to be 7.5 years which is moderate compared to other elasmobranchs (White 2014). However, this must be applied with caution as Shark Ray is in a monophyletic family with no co-generic species.
Generation Length (years):7.5

Use and Trade [top]

Use and Trade: When caught in Asia, it is often marketed locally for fins which are very valuable. This species is landed in Madagascar and Saudi Arabia but appears to be a very minor component of the catch (Robinson and Sauer 2013, Spaet and Beruman 2015). It has also been recorded in catches in India (Theivasigamani and Subbiah 2014) although the number taken in Indian fisheries is unclear. This species is a popular display animal in commercial aquaria (Last and Stevens 2009).

Threats [top]

Major Threat(s): The Shark Ray is one of the target species of Southeast Asian rhinid and rhynchobatid gillnet fisheries (W.T. White, pers. comm., 2003), 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). Flesh is sold for human consumption in Asia and the fins from large animals fetch particularly high prices. Demersal fisheries in Southeast Asia have experienced significant declines from overfishing and it is suspected that these declines will have affected this species (Stobutzki et al. 2006). 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.

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 2003, McAuley, unpubl. data). However, the introduction of turtle exclusion devices in northern Australian prawn trawl fisheries is likely to significantly reduce this species' mortality in trawl fishing gear (Zhou et al. 2008).

Conservation Actions [top]

Conservation Actions: The introduction of turtle exclusion devices (TEDs) in trawl nets of some Australian fisheries, has significantly reduced their capture of large elasmobranchs (Brewer et al. 1998). The introduction of TEDs in northern Australian fisheries and the Great Barrier Reef is likely to significantly reduce mortality of this species in these fisheries (Zhou, et al. 2008). Large marine parks such as the Great Barrier Reef that exclude trawling from large areas may further reduce mortality, however the effects of marine parks are uncertain as the species' movement and habitat use patterns are unknown.

Citation: McAuley, R.B., Compagno, L.J.V. & Chin, A. 2016. Rhina ancylostoma. The IUCN Red List of Threatened Species 2016: e.T41848A68641634. . Downloaded on 19 September 2018.
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