|Scientific Name:||Urolophus paucimaculatus|
|Species Authority:||Dixon, 1969|
|Taxonomic Notes:||There are potential issues regarding eastern and western subpopulations of the species and molecular work is probably needed.|
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor/s:||Trinnie, F.I., White, W.T. & Walker, T.I.|
|Reviewer/s:||Kyne, P.M., Fowler, S.L. & Compagno, L.J.V. (Shark Red List Authority)|
Urolophus paucimaculatus is an abundant endemic species distributed throughout southern Australia on sandy and seagrass substrates. This stingaree is a significant component of the bycatch of seine and trawl fisheries in southeastern and southwestern Australia, though its distribution far exceeds the extent of these fisheries. The species has no current commercial value but is edible and has the potential to be utilised in the future. Eastern and western populations may be distinct but further research is required to verify this. With a wide southern Australian distribution and its abundant status (abundance has increased in some areas, i.e., Port Phillip Bay, Victoria) the species is assessed as Least Concern. However, given the low fecundity of the species (1 to 2 young per year in WA; 1 to 6 per year in SE Australia), the high abortion rates among pregnant females landed by trawlers is the only real threat to this species and the catches of this species as bycatch should be monitored into the future.
|Range Description:||Urolophus paucimaculatus is known to inhabit most southern Australian continental waters where it is distributed widely across a variety of soft substrates, from shallow bays and inlets to the open continental shelf: from northern New South Wales (31°50?S) to Lancelin in Western Australia (31°00?S) including Victoria, Tasmania and South Australia (Last and Stevens 1994). The species has undergone a southward range expansion in recent decades.|
Native:Australia (New South Wales, South Australia, Tasmania, Victoria, Western Australia)
|FAO Marine Fishing Areas:||
Indian Ocean – eastern; Pacific – southwest
|Range Map:||Click here to open the map viewer and explore range.|
This species is one of the most abundant and widely distributed benthic chondrichthyans found in southern Australian waters, but little is not known about whether subpopulations or fragmentation occur. However, the southwestern population and the southeastern populations appear to be separated.
In Port Phillip Bay, Victoria, local abundances can be correlated with the catch of recreational and commercial benthic fish species and increases in the abundance of U. paucimaculatus were recorded from 1970 to 1991, probably due to a reduction in the abundance of competitors (Hobday et al. 1999).
|Habitat and Ecology:||
This species is demersal on the inner continental shelf over sandy and seagrass substrates from the shore to 150 m depth or more, including shallow bays and inlets (Last and Stevens 1994). In SE Australia it is generally found <80 m depth and occurs deeper in the Great Australian Bight. The species exhibits aplacental viviparity with uterine trophonemata and histotroph but demonstrates extreme atrophy of the left ovary and uterus. Ovulation occurs between spring and early summer in SE Australia. Litter size 1 to 2 in SW Australia and varies 1 to 6 in SE Australia, with larger mothers carrying more young than smaller mothers. Spontaneous abortion occurs at all sizes of pregnant animals when handled or caught in fishing gear. The sex ratio of embryos in SE Australia is 1:1.
Diet consists primarily of crustaceans, in particular mysids, carid decapods and amphipods (Platell et al. 1998).
Life history parameters for both SE Australia (Trinnie 2003) and SW Australia (White and Potter in prep) are given in the table below.
Life history parameters
Age at maturity: SE Aust: ~3 years at 50% maturity, SW Aust: 5 years (female); SE Aust: ~2.5 years at 50% maturity, SW Aust: 3 years (male).
Size at maturity (total length/dic width): SE Aust: 50% mature at 27 cm TL, SW Aust: 50% mature at 22.3 cm DW (female); SE Aust: 50% mature at 27.8 cm TL, SW Aust: 50% mature at 20.7 cm DW (male).
Longevity: SE Aust: 9+ years (females); 8+ years (males); SW Aust: 14 years.
Maximum size (total length/disc width): SE Aust: 50 cm TL (females); 42 cm TL (males); SW Aust: 27.2 cm DW.
Size at birth: SE Aust: ~15.0 to 15.5 cm TL; SW Aust: 12.6 cm DW.
Average reproductive age (years): Unknown.
Gestation time: SE Aust: ~1 year; SW Aust: 10 months.
Reproductive periodicity: 1 litter per annum.
Average annual fecundity or litter size: SE Aust: 1?6 dependant on maternal size; SW Aust: 1 to 2.
Annual rate of population increase: Unknown.
Natural mortality: Unknown.
SE Australia: Urolophus paucimaculatus is commonly taken as bycatch in Danish and inshore beach seines in the Southern and Eastern Scalefish and Shark Fishery (SESSF). The demersal monofilament gillnets and longlines of the shark fishery in southern Australia catch only small numbers and have no effect on the abundance of this species (Walker et al. 2002). Rapid risk assessment of the catch susceptibility defined from ?availability?, ?selectivity?, ?encounterability? and ?post-capture mortality?, rates this species as low to all fishing methods in the SESSF (T.I. Walker, unpublished data). Of animals caught and released, there would be some loss of aborting embryos in pregnant animals from the effects of capture and handling. Although encounterability and selectivity are high for demersal trawl, availability is low because most of the population is distributed outside the range of this fishery.
SW Australia: A trawl survey of demersal fishes on the coastal shelf regions of SW Australia in the early 1990s reported that U. paucimaculatus constituted 5.2% of the total biomass of fish caught (Laurenson et al. 1994, Hyndes et al. 1999). Only a small number of trawlers operate within the range of this species and no other fisheries catch urolophids in the SW portion of its range. Although females often abort embryos after capture, the low level of fishing pressure in SW Australia appears to be sustainable with respect to this species.
South Australia/Great Australian Bight: The species was reported as a negligible component of bycatch in the Spencer Gulf Prawn fishery by Carrick (1997). This fishery is part of the South Australian Prawn Fisheries and effort outside of Spencer Gulf and Gulf Saint Vincent is low. Indeed, a large portion of the range of U. paucimaculatus receives little fishing, i.e. large parts of inshore areas of the Great Australian Bight. The Great Australian Bight Trawl Sector of the SESSF operates at depths exceeding that of U. paucimaculatus.
Current monitoring of several areas in SE Australia is being conducted to better understand its population dynamics and to determine its life history characteristics. Research is required to determine if eastern and western populations are distinct.
The extensive network of (small) Marine Protected Areas in southern Australia will provide conservation benefits to this and other elasmobranch species.
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:||Trinnie, F.I., White, W.T. & Walker, T.I. 2006. Urolophus paucimaculatus. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 07 December 2013.|
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