Orectolobus

Charlie Huveneers, 2006, Redescription of two species of wobbegongs (Chondrichthyes: Orectolobidae) with elevation of Orectolobus halei Whitley 1940 to species level., Zootaxa 1284, pp. 29-51 : 29-30

[[ Genus Orectolobus ]]

Introduction

Wobbegong sharks (family Orectolobidae Gill 1896 ) are bottom-dwelling sharks found in warm temperate to tropical continental waters of the western Pacific (Compagno 2001). They can be distinguished from all other sharks (except angel sharks, family Squatinidae) by their flattened and variegated bodies, and from all other elasmobranchs by possessing dermal lobes along the sides of the head. Wobbegongs also have a short, nearly terminal mouth in front of the eyes, nasoral grooves, circumnarial grooves and flaps, symphysial grooves, large spiracles and dorsolateral eyes (Compagno 2001).

The family currently comprises seven valid species that are divided into three recognized genera: Eucrossorhinus consisting of E. dasypogon (Bleeker 1867) ; Orectolobus consisting of O. japonicus Regan 1906 , O. maculatus (Bonnaterre 1788) , O. ornatus (De Vis 1883) , O. wardi Whitley 1939 , and O. hutchinsi Last et al. 2006 ; and Sutorectus consisting of S. tentaculatus (Peters 1864) . The systematics of the family is not fully resolved and two new species of wobbegongs from Western Australia have recently been identified (P. Last and J. Chidlow personal communication). Furthermore, new material from Indonesia (W. White personal communication), Borneo (Manjaji 2002) and the Philippines (Compagno et al. 2005) suggests that additional species exist in the IndoWest Pacific.

Two species, O. ornatus and O. maculatus , are thought to occur off temperate eastern Australia, but it has been suggested that other closely related species-level taxa may also be present. Whitley (1940) described the subspecies O. ornatus halei , from southern Australia and distinguished it from O. ornatus ornatus from northeastern waters by “differences in its color pattern and in the form of the tentacles around the head”. No further description was given by Whitley apart for the size of the holotype of 288.3 cm. Furthermore, some specimens of O. ornatus are mature at 70-80 cm total length (TL) which is considerably smaller than the normal size of maturity at about 175 cm TL (Last and Stevens, 1994; Chidlow, 2001). This discrepancy between ‘small’ and ‘large’ morphs of O. ornatus was observed by Last and Stevens (1994) but they could not resolve the alpha taxonomy because of the paucity of research material. The small morph has since been observed mating (S. Hartley 2004 personal communication), and small pregnant females are regularly caught in the targeted wobbegong commercial fishery (Huveneers unpublished data). Apart from these reports, there has been no positive evidence to support the existence of a third species off eastern and southern Australia. The original description of O. ornatus halei was inadequate and it has subsequently been considered as a synonym of O. ornatus (Compagno 2001).

Wobbegongs have been targeted off the eastern Australian state of New South Wales (NSW) by commercial fishers for at least 15 years. However, catches have declined over the past decade leading to public concern about the potential impact of the fishery on wobbegong populations (NSW Department of Primary Industries 2001). There are minimal management strategies specifically regulating wobbegong fisheries in NSW. Those currently in place directly applying to wobbegongs are a recreational bag limit of two wobbegongs per day, gear limit of no more than ten lines each with a maximum of six hooks when setlining within three nautical miles of the coast, and the defacto protection given to shared critical habitats with grey nurse shark ( Carcharias taurus ). The lack of specific strategies directed at wobbegong commercial fishing and the decline in catches, has resulted in O. ornatus and O. maculatus being listed as ‘Vulnerable’ in the IUCN Red List in NSW and as ‘Near Threatened’ globally (Cavanagh et al. 2003). NSW Department of Primary Industries (NSW DPI) has expressed the need for appropriate management to ensure the viability of wobbegong populations in NSW (NSW DPI 2001). Suitable regulations require knowledge of all wobbegongs species marketed in NSW, especially if the sizes at maturity and reproductive biology differ between those species. Consequently, the subspecies needed to be investigated to help distinguish them and assess their conspecificity. These taxa are shown to be non-conspecific and both taxa are fully described below. A taxonomic key to Orectolobus species in NSW is also provided.