|Scientific Name:||Urolophus viridis|
|Species Authority:||McCulloch, 1916|
|Taxonomic Notes:||An inshore form off northwestern Tasmania may constitute an extremely narrow ranging sister species and this requires further investigation.|
|Red List Category & Criteria:||Vulnerable A2bd ver 3.1|
|Assessor/s:||Last, P.R. & Marshall, L.J.|
|Reviewer/s:||Kyne, P.M., Fowler, S.L. & Compagno, L.J.V. (Shark Red List Authority)|
A southeastern Australian endemic stingaree found on the continental shelf and onto the upper slope. The biology of this species is largely unknown but is likely to share reproductive characteristics with other urolophids including low fecundity (1 to 2 young per year). The species is taken as bycatch in trawl fisheries off eastern and southern Australia. It is not known to be utilized and is generally discarded, although survivability when caught from depth is unknown but likely low. Of further concern is the high rate of abortion amongst urolophids when caught and handled, particularly given their low fecundity. Fishery-independent trawl surveys comparing the bycatch of chondrichthyans between 1976 to 1977 and 1996 to 1997 off the New South Wales upper slope documented an overall decline in the catch rate of urolophids of 65.6%. Urolophus viridis and U. bucculentus were the commonly caught species, while U. sufflavus and U. cruciatus were taken in smaller quantities. When broken down by individual survey grounds, reductions in urolophid catch rates were 45.0% off Sydney, 81.2% off Ulladulla and 90.5% off Eden. Fishing pressure on these trawl grounds remains high. Such declines would qualify the species for an Endangered listing, however, reduced trawling pressure in Bass Strait and off the west coast of Tasmania, minimize threats in those areas. An assessment of Vulnerable is appropriate given documented declines, probable limited biological characteristics and the fact that southeastern Australia receives a high level of fishing pressure from several fisheries employing various gear types.
|Range Description:||Southeastern Australian warm temperate endemic: from Portland (Victoria) to Stradbroke Island (Queensland), including NSW and Tasmania.|
Native:Australia (New South Wales, Queensland, Tasmania, Victoria)
|FAO Marine Fishing Areas:||
Indian Ocean – eastern; Pacific – southwest; Pacific – western central
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||Formerly common throughout its range but impacted at least off NSW.|
|Habitat and Ecology:||
Demersal on soft substrates on the continental shelf. Recorded in depths of 20 to 200 m (mainly 80 to 180 m) by Last and Stevens (1994), but also occurs onto the upper continental slope as documented by Graham et al. (2001). No specific studies so biology largely unknown. Likely to have low fecundity (1 to 2 young/year) as with other urolophid species (for example see White et al. 2001).
Life history parameters
Age at maturity (years): Unknown.
Size at maturity (total length cm): Unknown (female; 27 cm TL (Last and Stevens 1994) (male).
Longevity (years): Unknown.
Maximum size (total length cm): 44 cm TL (Last and Stevens 1994).
Size at birth (cm): Unknown.
Average reproductive age (years): Unknown.
Gestation time (months): Unknown.
Reproductive periodicity: Unknown.
Average annual fecundity or litter size: Unknown.
Annual rate of population increase: Unknown.
Natural mortality: Unknown.
Fishery-independent trawl surveys comparing the bycatch of chondrichthyans between 1976?77 and 1996?97 off the New South Wales upper slope documented an overall decline in the catch rate of urolophids of 65.6% (Graham et al. 2001). Urolophus bucculentus and U. viridis were the commonly caught species, while U. sufflavus and U. cruciatus were taken in smaller quantities. When broken down by individual survey grounds, reductions in urolophid catch rates were 45.0% off Sydney, 81.2% off Ulladulla and 90.5% off Eden. Urolophus viridis was taken on all survey grounds (Graham et al. 2001). Fishing pressure on these trawl grounds as part of the Commonwealth-managed Southern and Eastern Scalefish and Shark Fishery (SESSF) remains high.
This species has a high ?availability? to shark gillnet gear and a high ?encounterability? and ?selectivity? to otter trawl gear in the SESSF. However, the species has a low ?catch susceptibility? to all gear types (including shark gillnet and otter trawl) used in the fishery (catch susceptibility is defined as ?availability? x ?encounterability? x ?selectivity? x ?post-capture mortality?; Walker 2004).
State-managed fisheries also operate in the area of occurrence and depth range of U. viridis, for example the NSW Oceanic Prawn Trawl Fishery and the Queensland East Coast Trawl Fishery (Eastern King Prawn Sector).
Of concern is the high rate of abortion amongst urolophids when caught and handled, particularly given their low fecundity.
Research is required on the species? biology. Bycatch monitoring is required in all fisheries within the species? range. Effort reduction and/or bycatch minimization in southeastern Australia fisheries is required to allow recovery and this and other depleted chondrichthyans.
Reduced trawling pressure in Bass Strait and off the west coast of Tasmania minimize threats in those areas.
The effective implementation of the Australian National Plan of Action for the Conservation and Management of Sharks (Shark Advisory Group and Lack 2004) (under the FAO International Plan of Action for the Conservation and Management of Sharks: IPOA?Sharks) will help to facilitate the conservation and sustainable management of all chondrichthyan species in Australia.
|Citation:||Last, P.R. & Marshall, L.J. 2006. Urolophus viridis. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 16 April 2014.|