|Scientific Name:||Aptychotrema vincentiana (Haacke, 1885)|
Rhinobates vincentianus Haacke, 1885
|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:||Last and Stevens (2009) suggest that there are subtle shape differences between populations in the southwest of Western Australia compared to those in the northwest of Western Australia (the Pilbara region). They also suggest that habitat differences exist, with those in the north being found found well offshore, while those in the south are found near the shore. This warrants further investigation.|
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor(s):||Morgan, D.L. & McAuley, R.B.|
|Reviewer(s):||Dulvy, N.K. & Kyne, P.M.|
|Facilitator/Compiler(s):||Kyne, P.M., Walls, R.H.L., Simpfendorfer, C. & Chin, A.|
The Western Shovelnose Ray (Aptychotrema vincentiana) is widely distributed across southern and western Australian coastal waters between Port Phillip Bay (Victoria) and Port Hedland (Western Australia); although there is some uncertainty regarding the taxonomy of the species within northwestern Australia (probably Shark Bay northwards). This species occurs in a variety of habitats, from shallow inshore waters to a depth of 125 m. It reaches a maximum size of around 100 cm total length and is one of the more productive rhinobatids with litter sizes of 14-16 pups. The Western Shovelnose Ray is taken in several commercial fisheries and although it is generally returned to the water (some catch is retained), some mortality is reported to occur in trawl fisheries and possibly during post-release. However, this species is assessed as Least Concern on the basis of being wide-ranging and common.
|Previously published Red List assessments:|
|Range Description:||The Western Shovelnose Ray is endemic to Australia, where it is found from the Kent Islands in Bass Strait, west across southern Australia, and north to Port Hedland in the Pilbara region of Western Australia (Last and Stevens 2009).|
Native:Australia (South Australia, Victoria, Western Australia)
|FAO Marine Fishing Areas:|
Indian Ocean – eastern
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||Some confusion surrounds the taxonomy of the species, which hinders population estimates. Last and Stevens (2009) suggest that there are subtle morphological differences between populations in the southwest of Western Australia compared to those in the northwest of Western Australia (the Pilbara region). They also suggest that habitat differences exist, with those in the north being found found well offshore, while those in the south are found near the shore.|
The Western Shovelnose Ray is relatively commonly encountered in the southwest of Western Australia, between approximately Cockburn Sound (near Perth) and Geographe Bay (near Dunsborough), but it is also encountered south and east to at least Albany (Jones et al. 2010). A few records exist in various museums for the South Australian Gulf and in Port Phillip Bay (Victoria). The Western Shovelnose Ray is the forth most commonly encountered elasmobranch in trawl catches of the lower west coast of Australia, where all life stages are captured (Jones et al. 2010).
|Current Population Trend:||Unknown|
|Habitat and Ecology:||This species appears to occupy vastly different habitats throughout its range. For example, those in southern Australia are generally found in nearshore waters, with small individuals occurring close to the shore, while those in northwest Australia (north of Exmouth), appear to be found in offshore waters (Last and Stevens 2009, Jones et al. 2010). However, taxonomic issues may need to be resolved between these areas (Last and Stevens 2009).|
The Western Shovelnose Ray attains a maximum size of at least 100 cm total length (TL), which is based on Jones et al. (2010) recording females up to 100.1 cm TL, and males up to 87.2 cm TL. The length at which 50% of the population attains maturity is 79.8 cm TL for females, and 64.2 cm TL for males (Jones et al. 2010). The smallest mature female recorded was 75.4 cm TL, while the smallest mature male recorded was 64.2 cm TL (Jones et al. 2010). Although small individuals are commonly encountered in littoral zones, they have been captured in southwestern Australia in deeper water commercial gillnet (24-73 m depth) and longline fisheries (65-73 in depth) (Jones et al. 2010), while maximum depth has been reported as 125 m (Last and Stevens 2009). The species is viviparous, with litter sizes of 14–16 (Haacke 1885).
|Continuing decline in area, extent and/or quality of habitat:||Yes|
|Congregatory:||Congregatory (and dispersive)|
|Use and Trade:||The Western Shovelnose Ray is not targeted by commercial fisheries, although 'not-specified' shovelnose rays are landed occasionally as byproduct; 1 tonne live weight was reportedly taken in 2012/13 in Western Australia (Fletcher and Santoro 2014). There is also likely to be some recreational take and consumption, particularly in southwestern Australia.|
The Western Shovelnose Ray is subject to capture in a variety of fisheries throughout its range, yet bycatch data for this species is relatively poorly reported. It is commonly encountered in trawl fisheries on the west coast and gillnet and longline fisheries on the southwestern and southern coasts of Western Australia (Jones et al. 2010). In this region, trawl fisheries appear to interact with all life stages and have the highest proportion of interactions, while gillnets capture a wide size range, and longlines interact with only the occasional animal (Jones et al. 2010). They are reported as bycatch from trawl fisheries in the West Coast Bioregion and Gascoyne Coast Bioregion (Evans and Molony 2012). Outside of Western Australia, the species is a likely bycatch in South Australian prawn trawl fisheries, while in the Commonwealth-managed Southern and Eastern Scalefish and Shark Fishery (SESSF), about 7 tonnes are estimated to be caught annually, with the bulk being discarded (Walker and Gason 2007).
Bycatch is likely to be highest in trawl fisheries, with exclusion devices less effective for smaller individuals (see Evans and Molony 2012). There are likely to be many habitats throughout their range that are not targeted by commercial trawl fisheries, in particular shallow waters <5 m where the species would receive refuge.
Jones et al. (2010) reported that many individuals caught in trawling died while in the nets, or suffered from injuries during capture and processing that were likely to lead to mortality, and predicted that over 50% of elasmobranchs captured using this method in this region died. These data are somewhat anecdotal, as these authors did not provide a species account of the proportion that had died or were injured, but it suggests relatively high mortality from capture.
|Conservation Actions:||It is recommended that levels of bycatch of this species are examined for all trawl fisheries throughout its range; particularly as all life stages may be affected within each fishery. Survivorship of released individuals also requires examination. The degree of ulitization of habitats and subsequent migration patterns requires assessment. The taxonomy and distribution patterns of the species requires examination. Biological attributes such as the age at maturity and longevity are also required.|
|Citation:||Morgan, D.L. & McAuley, R.B. 2015. Aptychotrema vincentiana. The IUCN Red List of Threatened Species 2015: e.T44186A68609294.Downloaded on 22 November 2017.|
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