Rhynchobatus australiae (Whitley, 1939)
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Rhynchobatus australiae (Whitley, 1939)

Genus: ,

Scientific Name: Rhynchobatus australiae

English Name: Whitespotted wedgefish

Creole Name: Vyolon

French Name: -

IUCN Red List Status: Critically Endangered (CR)

Description:

A large guitarfish with a triangular head form to pointed snout. Sandy brown in colour with white spots dorsally and white ventrally, and occasionally a black spot can 
be discerned on the dorsal surface of the base of each pectoral fin. Spines present dorsally along mid-line, on shoulder (in 2-3 short rows) beside spiracle and around 
upper margin of eye. Long bodied with large shark-like dorsal fins and short lower caudal fin. Large pectoral fins give body wedge-shaped form. Ventral mouth with teeth 
flattened to plates for crushing of shells etc. Large spiracle behind eyes.
 


Size:

Maturity: Males 130-145 cm TL, Females unknown. Max Length: Females to approx. 300cm TL.


Habitat and Ecology:

Benthic, inhabits insular and continental shelves on soft bottoms and near coral reefs to a depth of 60m or more. Feeds on crabs, molluscs and small teleosts. Its 
crushing teeth are adapted to break hard shells. Ovoviparous 4 pups per litter, gestation period unknown.


Fishery Status:

This species is not protected or subject to fishery regulations. It is caught primarily in the gill net fishery but also occasionally in the anchored long line ("drag") 
and hand line fisheries. It is highly sought after in Seychelles as its meat is considered the best of all the elasmobranchs and the fins are highly valued. Fishing 
methods can be modified to target the species.


Notes:

This species was previously classifed as R. djiddensis in Seychelles. Recent genetic studies have however confirmed the R. australiae identification. 
(D. A. Ebert, Moss Landing Marine laboratories, pers. comm. 2015).

Following a Green Islands Foundation GEF/Satoyama 2016-2018 project on threatened species in the arftisanal fishery, artisanal fishers agreed a minimum retention size 
for this species. This was agreed amongst measures for 12 other threatened species which have been submitted to the Ministry of Fisheries and the Seychelles Fisheries
Authority for promulgation into regulations. To date the Authorities have taken no action in this regard.


References:

Bray, D.J. 2017, Rhynchobatus australiae in Fishes of Australia, accessed 28 Aug 2018, http://fishesofaustralia.net.au/home/species/3273
Froese, R. and D. Pauly. Eds. 2018. FishBase. https://www.fishbase.de/summary/Rhynchobatus-australiae (28/08/18).
Kyne, P.M. et al (2019). Rhynchobatus australiae. The IUCN Red List 2019: e.T41853A68643043. https://dx.doi.org/10.2305/IUCN.UK.2019-2.RLTS.T41853A68643043.en. (28/09/21).
Last, P.R. et al (2016). Rays of the World. CSIRO Publishing ISBN 9781501705328
Nevill, J.E.G. et al (2015). An identification guide for the sharks of the Seychelles Artisanal Fishery.
White, W.T. & McAuley, R. (2003). Rhynchobatus australiae. The IUCN Red List 2003: e.T41853A10580429. http://dx.doi.org/10.2305/IUCN.UK.2003.RLTS.T41853A10580429.en. (28/08/18).


Citation:

Nevill, J.E.G. (2019). Rhynchobatus australiae, Whitespotted wedgefish. Seychelles Seatizens. www.seatizens.sc. http://seatizens.sc/species/rhynchobatus-australiae-whitley-1939/ (Updated 28/09/21).


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