|Scientific Name:||Urolophus mitosis Last & Gomon, 1987|
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor(s):||Last, P.R. & Marshall, L.J.|
|Reviewer(s):||Kyne, P.M., Fowler, S.L., Compagno, L.J.V. & Cavanagh, R.D. (Shark Red List Authority)|
A stingaree known only from off Port Hedland, northwestern Australia. Further data has not extended the range from this small area suggesting that it is extremely restricted. The population size is unknown, however, it is reasonably abundant through its known distribution. It appears to have a restricted bathymetric range, occurring in depths of about 200 m near the shelf break. Its area of occurrence and depth falls within the management area of the small-scale North West Slope Trawl Fishery (NWSTF). Although the area of this fishery is large, effort is centred outside the distribution of Urolophus mitosis and the main target species of the fishery (deepwater scampi) are generally fished at waters >300 m. Although some fishing is likely to occur at potential depths of U. mitosis, the vast majority of effort takes place in deeper waters and outside the geographical range of the species. Furthermore, increasing fishing effort is unlikely in the NWSTF due to economic constraints, thus the stingaree is assessed as Least Concern. However, given the narrowness of its range it could become severely impacted by any change in fishing activity, specifically through trawling, and could easily move into a threat category. Delicate animals caught at the depths in which this species occurs are likely to have low survivorship and gravid female urolophids are renowned for aborting embryos upon handling and capture. Extreme precaution is therefore warranted and the careful monitoring of bycatch data and fishing effort is recommended to ensure this species is not adversely impacted by any fishery changes in the future.
|Range Description:||Known only from off Port Hedland, Western Australia. Further data has not extended the range from the original description suggesting that it is extremely restricted.|
Native:Australia (Western Australia)
|FAO Marine Fishing Areas:|
Indian Ocean – eastern
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||Reasonably abundant through known range, but population size unknown.|
|Current Population Trend:||Unknown|
|Habitat and Ecology:||Occurs in depths of about 200 m (Last and Stevens 1994). Probably restricted to bathymetric range near the shelf break on soft substrates. 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); 25 cm TL (Last and Stevens 1994).
Longevity (years): Unknown.
Maximum size (total length): 29 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.
The range of this species overlaps with the management area of the North West Slope Trawl Fishery (part of the Commonwealth-managed Western Trawl Fisheries). This is a limited entry fishery with seven fishing permits granted on a five-yearly basis with fishing occurring from 200 m and deeper over a wide geographical area (AFMA 2003). Fishing is undertaken mainly on a part-time or opportunistic basis by trawlers from the Northern Prawn Fishery during closures in that fishery (Lynch and Garvey 2005). Although the area of the fishery is large, fishing for the main target species is confined to relatively small areas, principally centred around the Rowley Shoals and Scott and Ashmore Reefs (Lynch and Garvey 2005). The Rowley Shoals are close to the known area of occurrence of U. mitsis, but the shoals lie further to the east. The NWSTF targets three main species of deepwater scampi (Metanephropidae), which are distributed at depths of 260-500 m (Fowler and McLoughlin 1996). Of these three species, Metanephrops boschmai is taken at the shallowest depths (300-380 m) but represents the lowest volume of the three main scampi species (Lynch and Garvey 2005). Metanephrops velutinus is taken at 370-440 m and M. australiensis at 430-500 m (Lynch and Garvey 2005). Deepwater penaeid and carid prawns are an important byproduct of the NWSTF. Six species constitute 70% of the deepwater prawn catch in the fishery and these are caught at depths of 300-600 m (AFMA 2003).
It is therefore evident, that despite the range of U. mitosis overlapping with the area of the NWSTF there is little fishing activity on the shelf edge where the species has been recorded. Some fishing is likely to occur at potential depths of U. mitosis, but the vast majority of effort takes place in deeper waters and outside the geographical range of the species.
It is unlikely that fishing effort in the Western Trawl Fisheries will significantly increase in the future as the fisheries are presently considered to be "economically marginal" as a result of low product value, high operating costs and weather conditions (Edwards 2004).
Any urolopids taken from such depths as that of U. mitosis are likely to have low survivorship. Furthermore, gravid female urolophids are renowned for aborting embryos upon handling and capture.
Observer programs within the NWSTF need to be made aware of this species and bycatch data from the fishery needs to be analysed to examine if U. mitosis is being taken in the shallower areas of the fishery.
Any changes to current fishing practices need to ensure that they do not detrimentally affect the population of U. mitosis.
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 mitosis. The IUCN Red List of Threatened Species 2006: e.T60098A12251575.Downloaded on 25 September 2017.|
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