Ornate Wobbegong, Dwarf Ornate Wobbegong.
A small species of wobbegong with four groups of dermal lobes (skin flaps) below and in front of eyes on each side of head; no dermal lobes on chin; nasal barbel (closest to mouth) long and branched; three (rarely four) lobes in second preorbital group with outer lobes longer and branched; broad unbranched, spatulate post-spiracular lobes.
Two equally sized, large dorsal fins. First dorsal origin over pelvic fin insertion.
No warty tubercles on head or body. Body covered in an intricate pattern dominated by eight dark saddles edged with black lines. Saddles stand out against a light tan or grey background. Light brown and gray freckle-like blotches on and between saddles and on pectoral fins. Convergence of dark markings often leaves a light coloured V or X shape in front of eyes.
Note, previously thought to be the juvenile form of the species which was assumed to grow much bigger. Recent studies have shown that the larger morph is actually a distinct species now referred to as the Banded Wobbegong (Orectolobus halei).
Maximum length 110cm. Size at birth approximately 20cm.
Sub-temperate and tropical seas. The ornate wobbegong prefers areas with high topographic complexity and crevice volume on rocky and coral reefs, in kelp stands, and in sponge gardens. It can be found in bays, lagoons, on reef flats and faces, and around offshore islands. From the intertidal zone down to at least 100m.
The ornate wobbegong is probably confined to eastern Australia (Whitsunday Islands southward to Sydney) but may also be present in Indonesia and PNG.
I noticed a very similar looking wobbegong in Triton Bay on the south side of West Papua. At the time of writing (January 2020) DNA sampled are being processed.
The Ornate Wobbegong (Orectolobus ornatus) is a biologically sensitive species, site-attached within its relatively shallow water range and previously caught in commercial and recreational fisheries as a target species and as bycatch. In New South Wales, wobbegong catches combining all fishing methods and fisheries declined by more than 50% between 1997-98 and 2007-08 after which it stabilized to around 20 tonnes. This led to all three species of wobbegongs occurring in New South Wales, including the Ornate Wobbegong, to be regionally listed as Vulnerable in New South Wales. However, fishing effort reported as the number of days fished also declined between 1990-91 and 2008-09, resulting in catch rate being relatively constant around 15 kg per fishing days from 1990-91 until 2009. Fishing effort and ensuing catch rate should, however, be used with caution because it is coarsely reported as the number of days fished and does not account for the number of hooks used or soak times. Since September 2006, wobbegongs have been included in the daily trip limit for a specific list of shark species to one tonne for a 24 hour period and two tonnes for 48 hours or greater. New management regulations in May 2008 introduced a daily limit of six wobbegongs. A minimum size limit of 180 cm for the Ornate Wobbegong and the Banded Wobbegong (O. halei) implemented between 2008 and 2013 effectively protected the Ornate Wobbegong since its maximum size is about 120 cm total length. Although the minimum size limit is no longer applicable, wobbegongs are no longer targeted to the same extent as they used to because of the trip limit implemented in 2008. In addition, further investigation of the New South Wales fishing catches and effort revealed that the catch per unit effort did not decrease as thought in the previous assessment. As a result, there is no evidence to infer or suspect population decline of the Ornate Wobbegong, and current catches are relatively low and not spread across the species’ distribution, resulting in the species being listed as Least Concern.
Citations and References
Huveneers, C., Pollard, D.A., Gordon, I., Flaherty, A.A. & Pogonoski, J. 2015. Orectolobus ornatus. The IUCN Red List of Threatened Species 2015: e.T41838A68638906. https://dx.doi.org/10.2305/IUCN.UK.2015-4.RLTS.T41838A68638906.en. Downloaded on 03 January 2021.
Ovoviparous and probably lecithotrophic, i.e. the foetus is solely nourished by the yolk within the egg case. 4-18 pups per litter. Gestation 10-11 months. Triennial reproductive cycle
Feeds on small bony fishes, elasmobranchs, cephalopods, and crustaceans.
Wobbegongs are ambush predators that remain motionless while camouflaged against the reef. When an appropriately sized fish swims in front of its disguised mouth, the wobbegong lunges forward simultaneously stretching its mouth open. The process sucks water and fish into its mouth, which immediately snaps shut again, trapping its prey with needle-like teeth.
Nocturnal. Rests by day under reef ledges or in caves. Relocates at night when hunting but often returns at dawn to the same resting spot. In Nelson Bay an ornate wobbegong was re-sighted within a 75 hectare area for a period of over 211 days (Carraro and Gladstone 2006) suggesting a great degree of site fidelity.
Reaction to divers
Very easy to approach. 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 ornate wobbegong is a commonly encountered species in New South Wales. One of the best spots is Fish Rock near the town of Southwest Rocks. Spotted and banded wobbies are more common at this location but I have seen ornate wobbegongs resting in the shallows on top of the pinnacle.
Byron Bay is also a good spot to encounter this species.
Further south in Nelson Bay, I seen a lot of ornate wobbegongs, lounging on sponges. This makes the latter a good spot for colourful images when the visibility is good.
Banded/Gulf Wobbegong Once thought to be the adult form of the ornate wobbegong. Distinguished by much larger size and similar but less intricate markings.
Papuan Wobbegong a very similar looking wobbegong found in West Papua and PNG. At the time of writing (January 2020) DNA sampled are being processed to establish whether these two species are distinct or regional variants of eachother.