Cobbler Wobbegong: Sutorectus tentaculatus

Family: Orectolobidae
Common name(s)

Cobbler Wobbegong.

Identification

A relatively small species of wobbegong that is less dorsally compressed than other orectolobids. Nasal barbells unbranched. Two simple unbranched preorbital dermal lobes, and two simple post-spiracular dermal lobes. The posterior-most dermal lobe may be indistinct.
Two equally sized, long, low dorsal fins. First dorsal origin anterior to pelvic fin insertion. Notch present midway along terminal margin of caudal fin (posterior to subterminal notch).
Distinct warty (crocodile-like) tubercles on top of head and body. Dorsum pattern consists of large reddish brown and/or orange areas, broken up by white or cream irregular spots.

Size

Maximum verified length 92cm. Size at birth approximately 22cm. Age at maturity 60-65cm.

Habitat

Temperate seas. Found on rocky and coral reefs, and in kelp. To at least 35m depth.

Distribution

The cobbler wobbegong is confined to south and west Australia. From Adelaide west and northwards to the Abrolhos Islands.

Conservation Status

LEAST CONCERN

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).

Citations and References
Huveneers, C. & Simpfendorfer, C. 2015. Sutorectus tentaculatusThe IUCN Red List of Threatened Species 2015: e.T41864A68646166. https://dx.doi.org/10.2305/IUCN.UK.2015-4.RLTS.T41864A68646166.en. Downloaded on 04 January 2021.

Reproduction

Ovoviparous and likely lecithotrophic, i.e. the foetus is solely nourished by the yolk within the egg case. Maximum litter size at least 12 pups.

Diet

Bony fishes.

Behavior

Nocturnal. Rests by day on reef ledges or in weeds.

Reaction to divers

Very easy to approach. Remains at rest, relying on camouflage unless closely harassed.
CAUTION: Wobbegongs have been reported to have bitten divers that moved too close to their mouths, even when not disturbed.

Diving logistics

The cobbler wobbegong is a rarely encountered species. To date, I have found one animal; at 15m among kelp/weeds in Bremer Bay, W.A.

Other divers have reported encounters at Perth and Albany, and at Whyalla in South Australia.

Similar species

Other Wobbegongs All other wobbegong species can be easily distinguished by a lack of warty dermal tubercles on head and back.