Northern Wobbegong, Ward’s Wobbegong.
A small species of wobbegong. Nasal barbells unbranched. Two unbranched preorbital dermal lobes and two wide, unbranched post-spiracular dermal lobes.
Two equally sized, large dorsal fins. First dorsal origin over pelvic fin insertion.
No warty tubercles on head or body. Dorsal colour pattern simpler than other wobbegongs. Five dark saddles/bands with pale margins on head and torso. Saddles separated by a network of lighter spots and blotches with pale margins.
Maximum verified length 63cm. Possibly up to 100cm. Size at birth unknown.
Tropical seas. Prefers shallow coral or rocky reefs, usually in turbid water.
Found on the northern coast of Australia, from Coral Bay and Ningaloo Reef in W.A. to Cape York in northern Queensland. Possibly also present in southern Indonesia and PNG.
Although most fisheries do not record catch to species level, the small size and reef associated habits of the Northern Wobbegong probably prevents it from coming in contact with most gear types. Threat from fisheries interaction is therefore thought to be minimal. The Northern Wobbegong occurs within the Western Australian (WA) northern shark fisheries area. The ‘northern shark fisheries’ comprise the state managed WA North Coast Shark Fishery (WANCSF) in the Pilbara and western Kimberley, and the Joint Authority Northern Shark Fishery (JANSF) in the eastern Kimberley. The primary fishing method employed in these fisheries is demersal longline, with a relatively small amount of pelagic gillnetting occurring in the JANSF. Although these fisheries overlap the species range, no wobbegongs have been reported in the catch (G. Johnson, pers. comm., February 2015).
Smaller wobbegongs may occur in commercial rock lobster pots in Western Australian waters (Chidlow et al. 2007). Observers of the Pilbara Fish Trawl Fishery recorded two wobbegongs from the ‘wardi-complex’ collected between February and June 2002 (McAuley et al. 2005). However, as all sharks and rays are now commercially protected throughout Western Australia, state managed commercial fishing vessels cannot generally retain wobbegongs, unless they are operating in the managed shark fishery. Incidental bycatch is therefore, expected to be discarded with good potential for post-release survival.
The Northern Territory Offshore Net and Line Fishery accounts for 95% of the Northern Territory’s shark take, and does not record wobbegongs. Possession of sharks and shark product is prohibited for the Timor Reef, demersal and fin-fish Trawl fisheries. Incidental bycatch is again expected to be infrequent in this jurisdiction (Handley 2010).
The number of wobbegongs caught by recreational fishing from boat licence holders in Western Australia during 2011–12 was estimated at 1,535 animals, with 20% retained (304) and 5% caught from the North Coast region (Ryan et al. 2013), resulting in ~15 wobbegongs caught annually within the distribution of the Northern Wobbegong.
Citations and References
Huveneers, C., Corrigan, S. & Pillans, R.D. 2015. Orectolobus wardi. The IUCN Red List of Threatened Species 2015: e.T41839A68639575. https://dx.doi.org/10.2305/IUCN.UK.2015-4.RLTS.T41839A68639575.en. Downloaded on 04 January 2021.
Ovoviparous. Presumably lecithotrophic, (wherein the foetus is solely nourished by the yolk within the egg case) like other wobbegongs. Reproductive cycle poorly known.
Feeds on small bony fishes and invertebrates.
Nocturnal. Rests by day under reef ledges, usually in turbid water.
Reaction to divers
Easy to approach (once finally located). Remains at rest, relying on camouflage unless harassed.
CAUTION: Wobbegongs have been reported to have bitten divers that got too close to their mouths, even when not disturbed.
The northern wobbegong is occasionally seen on Ningaloo Reef but the easiest place to locate one is probably the navy pier at Exmouth, W.A. This area is at the southwestern edge of this species range so it may be more common further north and east but conditions become increasingly more turbid as one travels north from Exmouth.
Network Wobbegong Quite similar but distinguished by dark saddles containing eye-sized black spots, and black spots on the pectoral fins.
Northern Wobbegong Complex O. wardi appears to be part of a species complex that may be split into more species once further research has taken place.