|Scientific Name:||Sutorectus tentaculatus (Peters, 1864)|
|Taxonomic Notes:||Synonym = Orectolobus tentaculatus.|
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor(s):||Huveneers, C. & Simpfendorfer, C.|
|Reviewer(s):||Walls, R.H.L. & Kyne, P.M.|
|Facilitator/Compiler(s):||Kyne, P.M., Walls, R.H.L., Simpfendorfer, C. & Chin, A.|
The Cobbler Wobbegong (Sutorectus tentaculatus) is a small (to at least 92 cm total length) Australian endemic. This species is known only from shallow waters on the continental shelf off southwest and southern Australia, between the Houtman Abrolhos (Western Australia) and Adelaide (South Australia), at depths to at least 35 m. Although little is known about the biology of the species, it is a minor bycatch component of the Western Australian temperate demersal gillnet and demersal longline fisheries, which only catch ~40 tonnes of wobbegongs per year, and minimal catches in other parts of its distribution. In addition, the Cobbler Wobbegong is unlikely to be retained due to its small size and post-release survival of wobbegongs is expected to be high. Further research is required on the species' biology, occurrence and capture in fisheries, but there is no evidence to infer or suspect population decline, so the species is listed as Least Concern.
|Previously published Red List assessments:|
|Range Description:||The Cobbler Wobbegong is an Australian endemic, known only from the inner continental shelf off southwest and southern Australia, from Houtman Abrolhos in Western Australia to Adelaide in South Australia (Last and Stevens 2009).|
Native:Australia (South Australia, Western Australia)
|FAO Marine Fishing Areas:|
Indian Ocean – eastern
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||Nothing is currently known of the population size or trend of this species, but it appears to be most common in southwest Western Australia. No information is available on the existence of subpopulations.|
|Current Population Trend:||Unknown|
|Habitat and Ecology:||The Cobbler Wobbegong occurs on rocky reef and weedy areas on the continental shelf to at least 35 m depth (Last and Stevens 2009). Little is known of its ecology, but like other wobbegongs it is unlikely to move large distances, spending most of its time lying on the seabed. |
A small species growing to at least 92 cm total length (TL), with males maturing at about 65 cm TL, and size at birth approximately 22 cm TL. Since the reproductive mode of all other wobbegongs (family Orectolobidae) is lecithotrophic viviparity, it is likely that the Cobbler Wobbegong has a similar reproductive mode (Huveneers et al. 2007, Huveneers et al. 2011). Chidlow (2003) reported only one pregnant female which contained 12 developing embryos with a sex ratio strongly biased towards males.
|Use and Trade:||
In Australia, wobbegong flesh is sold locally for human consumption through ‘fish and chip’ and fresh fish retail outlets. Most commercially landed wobbegong catch however, is comprised of larger species. Due to their low commercial value, smaller individuals are usually released alive. Given its small size, use and trade of the Cobbler Wobbegong in Western Australian commercial fisheries is therefore expected to be minimal. Wobbegong fins have no known commercial value. Historically, the attractive skin has been used as decorative leather (Last and Stevens 2009). However, it is unknown if this practice is still occurring.
The Cobbler Wobbegong is a small component of the bycatch of the Western Australian temperate demersal gillnet and demersal longline fisheries. The species, along with other wobbegong species occurring within the region, is primarily caught by demersal gillnets off the southern and lower west coasts of Western Australia. A fisheries-dependent survey of southwest Western Australia fisheries reported that the Cobbler Wobbegong constituted 0.9% of total elsamobranch catches from gillnets (Jones et al. 2010). Wobbegongs were historically also caught by a few vessels using demersal longlines in the same fishery until the use of that gear was restricted in 2006. The Western Australian temperate demersal gillnet and demersal longline fisheries mean annual wobbegong catch is about 40 tonnes per year (range 28-68 tonnes) between 1999 and 2014 and does not show any sign of decline (Department of Fisheries WA Fishery Status Report 1998-99 to 2013-14, for example, Braccini et al. 2014). Although wobbegong catches are generally not reported to individual species, small wobbegongs (<150 cm) are selectively discarded alive (Chidlow et al. 2007, R. McAuley, pers. comm,, February 2015) due to low flesh recovery rates from smaller individual. Thus, the Cobbler Wobbegong is believed to be a minor component of those aggregated catches. In addition, post-release survival of wobbegongs is thought to be high.
In South Australia, the Cobbler Wobbegong is caught as bycatch in the Spencer Gulf and Gulf St Vincent prawn trawl fishery (Currie et al. 2009, SARDI unpubl. data). A survey of the Spencer Gulf prawn trawl fishery showed that the Cobbler Wobbegong was caught in 11 of the 120 sites sampled (Currie et al. 2009). The Cobbler Wobbegong is not retained and likely to have high post-release survival rates.
Small wobbegongs also occur in commercial rock lobster pots throughout temperate coastal Western Australian waters (Chidlow et al. 2007). However, as all sharks and rays are now commercially protected throughout Western Australia, wobbegongs cannot generally be retained by State managed commercial fishing vessels unless they are operating in the managed shark fishery.
The retained catch of wobbegongs by recreational fishers off the west coast of Australia has been estimated at approximately 1,000 animals per year (Sumner and Williamson 1999), while the estimated annual catch during 2011–12 by recreational fishing from boat licence holders was 1,535 wobbegongs, with 20% or 304 individuals retained (Ryan et al. 2013). Assuming the species composition of recreational wobbegong catches is similar to that of the commercial gillnet fishery, the Cobbler Wobbegong is also likely to be a minor component of recreational catches.Although the Cobbler Wobbegong occurs within the western extent of the Southern and Eastern Scalefish and Shark Fishery, the species is not or only rarely caught by this fishery (Walker and Gason 2007).
All sharks and rays are commercially protected under Western Australian law. This regulation essentially restricts the retention of all shark and ray products by commercial fishing vessels other than those operating in the State’s managed shark fishery. The likely small quantity of incidental Cobbler Wobbegong bycatch is therefore believed to be discarded alive. Although not directly tested, observational evidence suggests that wobbegongs are a hardy group. Trap caught individuals can be released in good condition and post-release survival is presumed likely.
Relative to the area known to be occupied by the Cobbler Wobbegong, shark fishing effort (mainly demersal gillnet) is sparsely distributed and managed within specific regional limits via time-gear input controls. For example, the Metropolitan Fishing Zone, between Lancelin and south of Mandurah, was closed to commercial line and gillnet fishing in 2007 as part of a fishing reform package to ensure sustainability of fish for the future. The managed shark fishery's catches and fishing effort are also routinely monitored through analyses of statutory daily/trip logbook data and the fishery's target stocks are subject to regular stock assessments.
The use of commercial shark fishing gear (large mesh gillnets and demersal longlines) is prohibited north of 26°30’S latitude to 120'E longitude off the north coast, which may include the northern extent of the species’ range. The use of metal snoods (gangions) is commercially prohibited throughout Western Australian waters (except for a small amount of demersal longline effort in the managed shark fishery and pelagic mackerel troll lines). Recreational fishers are subject to a daily bag limit of two sharks per person.
Site attached species such as wobbegongs may also benefit from habitat protection and suitably designed and implemented no-take zones, where all forms of harvesting or fishing are excluded (Huveneers et al. 2006, Lee 2014). This species is potentially protected in the following Australian marine protected areas, marine parks and nature reserves:
Shark Bay Marine Park, WA
Jurien Bay Marine Park, WA
Hamelin Pool Marine Nature Reserve, WA
Shoalwater Islands Marine Park, WA
Marmion Marine Park , WA
|Citation:||Huveneers, C. & Simpfendorfer, C. 2015. Sutorectus tentaculatus. The IUCN Red List of Threatened Species 2015: e.T41864A68646166.Downloaded on 20 October 2017.|
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