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Dipturus apricus

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA CHONDRICHTHYES RAJIFORMES RAJIDAE

Scientific Name: Dipturus apricus
Species Authority: Last, White & Pogonoski, 2008
Common Name(s):
English Pale Tropical Skate
Taxonomic Notes: This is a recently described new species of skate (Last et al. 2008). The Pale Tropical Skate (Dipturus apricus) was previously referred to as Raja sp. G by Last and Stevens (1994).

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2011
Date Assessed: 2010-11-22
Assessor(s): Rigby, C.
Reviewer(s): Ebert, D.A. & Kyne, P.M.
Justification:
The Pale Tropical Skate (Dipturus apricus) is a medium-sized skate that is endemic to northeastern Australia. This species has a distribution restricted to an area off central Queensland where it occurs in depths of 195–605 m. The Pale Tropical Skate is found commonly throughout its range and considered one of the most abundant rays on the upper continental slope off central Queensland, yet little is known of its biology or population trends. It is not known if this species is of commercial value, though it is unlikely. Threats to this species are currently minimal as there is low fishing effort in the area of its occurrence. Future increases in fishing pressure within its range may pose a risk due to the restricted geographic range, however Australian fisheries are relatively well managed with ongoing ecological risk assessments conducted that take biological factors into account and give an indication of which species are at high risk from fishing in each fishery. Under this process, any changes in fishing activity and effort should be considered which may reduce the level of any potential future risks to species such as this skate. Despite this skate being poorly known, there presently are no apparent considerable threats to the population, so the status of Least Concern is appropriate.

Geographic Range [top]

Range Description: The Pale Tropical Skate is endemic to northeastern Australia in the Western Central Pacific with a distribution restricted to off the Queensland coast; from Hinchinbrook Island, Cardwell to east of the Bunker Group, Gladstone (Last et al. 2008, Last and Stevens 2009).
Countries:
Native:
Australia (Queensland)
FAO Marine Fishing Areas:
Native:
Pacific – western central
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: The Pale Tropical Skate occurs commonly throughout its range and is one of the most abundant rays on the upper continental slope off central Queensland (Last and Stevens 2009). There is no other information about the population trends or structure.
Population Trend: Unknown

Habitat and Ecology [top]

Habitat and Ecology:

The Pale Tropical Skate is demersal on the upper continental slope, in depths of 195–605 m, though it occurs mainly in 300–500 m (Last et al. 2008, Last and Stevens 2009). This skate attains at least 77 cm total length (TL) with adult females larger than males. The males mature from 55–66 cm TL and this species is born at about 15–17 cm TL (Last and Stevens 2009).

Systems: Marine

Use and Trade [top]

Use and Trade: The use and trade of the Pale Tropical Skate is unknown.

Threats [top]

Major Threat(s):

The main threat that may affect the Pale Tropical Skate is fishing which has the potential to cause direct and indirect mortality and habitat modification. However, the current demersal fishing pressure across this species’ range is generally very low. The area of the Australian Commonwealth managed Coral Sea Fishery (CSF) lies mostly to the east of the distribution of the Pale Tropical Skate, overlapping only marginally with the species’ range. It is possible but unlikely that this skate is taken as bycatch in the Line and Trap Sector, and Trawl and Trap Sector of this fishery. While line, trawl and trap gear could capture this species as it fishes at the depths this species occurs, they are relatively small-scale fisheries with only a small number of vessels operating across both sectors in recent years and with no trawl fishing effort over the last two years (Furlani et al. 2007a,b; Woodhams et al. 2010). The management area of the fishery is far greater than the range of the Pale Tropical Skate, with the majority of fishing effort outside of the species’ occurrence.

The Queensland managed Deep Water Fin Fish Fishery operates in all Queensland east coast waters east of the 200 m bathymetric line and does overlap this species’ distribution. However it uses benthopelagic rather than truly demersal gear, and most of the fishing effort, which is low with only four active licences, is in areas where the 200 m depth contour is relatively close to the coast. In recent years the majority of the effort has been much further south than the range of this skate (DEEDI 2009). The deepwater eastern king prawn sector of the Queensland managed East Coast Trawl Fishery that operates to depths of 300–350 m could possibly take this species as bycatch at the southern limit of its distribution though the majority of effort in this fishery sector is further south (Courtney and Posser 2009). This species has not been recorded in the commercial and research surveys of the bycatch of this fishery sector (Courtney et al. 2007).

Conservation Actions [top]

Conservation Actions:

There are no conservation actions currently in place for this species. Research is needed on its life history characteristics and further survey work would be beneficial to confirm the limits of this species’ known distribution.

The Australian Commonwealth Government recognize that the line and trawl sectors of the CSF may pose a risk to chondrichthyans that occur deeper than 200 m. Though catches of chondrichthyans are extremely low and infrequent in the CSF, the Australian Fisheries Management Authority has taken a precautionary and proactive approach in recognition that they may be more susceptible than others to overfishing due to their low rates of reproduction. All deepwater sharks brought aboard live must be released alive, while a very small quantity of any dead animals may be retained by way of trip limits introduced in July 2010 to facilitate the collection of information on species occurrence. These trip limits do not currently include skates and rays as these are incidental to the catch and are released (AFMA 2010).


Citation: Rigby, C. 2011. Dipturus apricus. The IUCN Red List of Threatened Species. Version 2014.3. <www.iucnredlist.org>. Downloaded on 19 December 2014.
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