|Scientific Name:||Urolophus lobatus|
|Species Authority:||McKay, 1966|
|Red List Category & Criteria:||Least Concern ver 3.1|
|Reviewer(s):||Kyne, P.M., Fowler, S.L. & Compagno, L.J.V. (Shark Red List Authority)|
A small Eastern Indian endemic stingaree from southwestern Australia (the state of Western Australia) common in shallow water over sand and seagrass to 30 m depth. Although Urolophus lobatus forms a considerable component of the biomass of bycatch in the scallop and prawn trawl fisheries that operate off Perth and Mandurah (northernmost part of their range), this species is of no commercial value and those caught by trawlers are typically returned alive. Only a small number of trawlers operate in this fishery, and no other fisheries appear to catch urolophids in the range of this species. Given the low fecundity of the species (1 to 2 young per year), 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 (particularly given the species' relatively narrow geographical and bathymetrical range).
|Range Description:||Found only on the continental shelf off southern Western Australia between Esperance (121°53'E) and Rottnest Island (32°00'S) (Last and Stevens 1994).|
Native:Australia (Western Australia)
|FAO Marine Fishing Areas:||
Indian Ocean – eastern
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||Very common over scallop and prawn trawl grounds on the upper continental shelf off the lower west coast of Australia.|
|Habitat and Ecology:||
Urolophus lobatus is a common species found over sand and seagrass habitats on the upper continental shelf in depths of 1 to 30 m (Last and Stevens 1994). Aplacental viviparous species with ovulation and conception occurring in January and parturition occurring 10 months later, i.e., October/November (White et al. 2001). Litter size ranges from one to two and females reproduce each year. Females and males are mature at 20 cm DW and 16 cm DW, respectively, and attain maximum sizes of 27.7 cm DW and 23.7 cm DW, respectively (White et al. 2001).
Females and males are mature by the end of their third and second years of life, respectively, and reach maximum ages of 14 and 12 years, respectively (White et al. 2001). Von Bertalanffy growth parameters for both sexes were: DWinf = 24.9 cm (F) and 21.1 cm (M), t0 = -1.35 (F) and -1.18 (M) years, k = 0.37 (F) and 0.51 (M).
Diet consists primarily of crustaceans, in particular mysids, carid decapods and amphipods (Platell et al. 1998). Life history parameters from White et al. (2001).
Life history parameters
Age at maturity: 3 years (female); 2 years (male).
Size at maturity (disc width): 20 cm DW (female); 16 cm DW (male).
Longevity: 14 years (females); 12 years (males).
Maximum size (disc width): 27.7 cm DW females; 23.7 cm DW males.
Size at birth: 10.5 cm DW.
Average reproductive age (years): Unknown.
Gestation time (months): 10 months.
Reproductive periodicity: 1 litter per annum.
Average annual fecundity or litter size: 1 to 2 young per annum.
Annual rate of population increase: Unknown.
Natural mortality: Unknown.
This species forms a considerable component of the biomass of bycatch in the scallop and prawn trawl fisheries that operate off Perth and Mandurah (northernmost part of their range). A trawl survey of demersal fishes on the coastal shelf regions of southwestern Australia in the early 1990s reported that U. lobatus constituted 4.8% 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.
This species is of no commercial value and all those caught by trawlers are returned alive. The only real concern for this species and other urolophids is that a large percentage of pregnant females landed abort their young before they are returned (White et al. 2001). Since the fecundity of this species is so low (one to two) and gestation is relatively long (10 months), any additional fishing pressure could have a significant effect on populations of this species.
This species is not generally caught by recreational fisherman. There are no real threats from pollution within the range of this species.
None in place. Monitoring of this species and other elasmobranchs caught as bycatch in southwestern Australia should be conducted to establish whether the population sizes are stable or declining. A follow-up trawl survey, identical to that conducted in the early 1990s, on the lower west coast of Australia should be conducted to determine any trends in population sizes of such 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:||White, W.T. 2006. Urolophus lobatus. The IUCN Red List of Threatened Species. Version 2014.3. <www.iucnredlist.org>. Downloaded on 18 December 2014.|