|Scientific Name:||Rhinobatos salalah|
|Species Authority:||Randall & Compagno, 1995|
|Taxonomic Notes:||Revision of the large genus Rhinobatos is proposing to elevate subgenera Acroteriobatus to generic status, thus Rhinobatos salalah will be referred to as Acroteriobatus salalah. However, these changes are not yet published and until such time as they are the species should continue to be referred to as Rhinobatos salalah.
Distinct but only known from one specimen. Could be confused and misidentified as Rhinobatos obtusus Müller & Henle, 1841 or R. blochii Müller & Henle, 1841.
|Red List Category & Criteria:||Data Deficient ver 3.1|
|Assessor(s):||Compagno, L.J.V. & Marshall, A.D.|
|Reviewer(s):||Kyne, P.M., Heupel, M.R. & Simpfendorfer, C.A. (Shark Red List Authority)|
Rhinobatos salalah is known from a single specimen (a 54 cm total length male) collected at the Salalah fish market, western Oman. Its distribution is therefore unknown, but as efforts to find additional specimens in fish markets and in underwater surveys have failed to produce any other individuals it may have a very restricted distribution in the Arabian Sea. Guitarfish are a regular component of both directed and bycatch landings in the Western Indian Ocean and the Red Sea. Threats to this species are unknown due to the lack of information on distribution and fisheries data. However, coastal rhinobatids are susceptible to capture in a variety of fishing gear including trawl, gillnet, line and seine net and their occurrence along inshore areas of the continental shelf makes these rays an easy target for such fisheries. Declines of several species of inshore rhinobatids have been documented globally and present levels of catches are of concern in many regions. Limited available information precludes assessment beyond Data Deficient at present, and further specimens of this potentially vulnerable species are required to accurately define its range, biology and extent of catches in local fisheries.
|Range Description:||Coastal shelf of Oman – Arabian Sea.|
|FAO Marine Fishing Areas:||
Indian Ocean – western
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||Only known from a single specimen collected at a fish market in Salalah, western Oman. Extent of range is unknown but may be very restricted in the Arabian Sea.|
|Current Population Trend:||Unknown|
|Habitat and Ecology:||Presumably bottom dwelling like other similar species of guitarfish. Nothing known of the species' biology but rhinobatids are aplacental viviparous.
Life history parameters
Age at maturity (years): Unknown.
Size at maturity (total length cm): Unknown.
Longevity (years): Unknown.
Maximum size (total length): At least 54 cm TL (Randall and Compagno 1995).
Size at birth (cm): Unknown.
Average reproductive age (years): Unknown.
Gestation time (months): Unknown.
Reproductive periodicity: Unknown.
Average annual fecundity or litter size: Unknown.
Annual rate of population increase: Unknown.
Natural mortality: Unknown.
Threats to this species are unknown because of the lack of information on distribution and fisheries data. However, coastal rhinobatids are susceptible to capture in a variety of fishing gear including trawl, gillnet, line and seine net and their occurrence along inshore areas of the continental shelf makes these rays an easy target for such fisheries. Target fisheries for guitarfish currently exist in several countries particularly in the Indo-West Pacific and declines in some species have been documented. For example, Rhinobatos horkelii has been significantly impacted by heavy inshore fishing pressure where it occurs in Brazil. Similarly declines are now been observed in species in Southeast Asia, for example Rhinobatos granulatus and others. Species are impacted by direct and indirect fishing pressure where the flesh is utilised and the demand for fins for the international fin trade could be a factor in the switch from subsistence fisheries to more directed, commercial export fisheries of especially the larger guitarfish in areas such as Indonesia and the Philippines. Habitat requirements are not well understood, but inshore areas are important as nursery areas and these are being impacted upon by fishing activities and environmental degradation/pollution. Reproductive biology of rhinobatids is reasonably well studied compared with other batoid groups. Rhinobatos species tend to have an annual reproductive cycle producing a single litter per year of between 2-16 pups. While catch numbers are not readily available, regional populations are expected to be decreasing in areas where these susceptible species are fished.
Further fish market surveys in Oman failed to produce any other specimens of this species, so it is not known to what extent the species is being landed in Oman.
In the first instance there is a requirement to obtain further specimens of this species in order to accurately document its distribution and occurrence in local fisheries. Information is also required on the species' biology. A better understanding of habitat requirements and critical area/habitats is also required.
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 management of all elasmobranch species. At the time of writing, Oman had shown an intention to develop a National Plan of Action (Anon. 2004).
|Citation:||Compagno, L.J.V. & Marshall, A.D. 2006. Rhinobatos salalah. The IUCN Red List of Threatened Species 2006: e.T60172A12316627. . Downloaded on 05 May 2016.|
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