Notoraja sticta 


Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Chondrichthyes Rajiformes Arhynchobatidae

Scientific Name: Notoraja sticta
Species Authority: McEachran & Last, 2008
Common Name(s):
English Blotched Skate
Taxonomic Notes: Four Notoraja species were previously identified by Last and Stevens (1994) but remained undescribed until recently (McEachran and Last 2008, Last and Stevens 2009).

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2015
Date Assessed: 2015-02-19
Assessor(s): Beckmann, C. & Huveneers, C.
Reviewer(s): Walls, R.H.L. & Kyne, P.M.
Contributor(s): Kyne, P.M. & Walls, R.H.L.
Facilitator/Compiler(s): Kyne, P.M. & Walls, R.H.L.

The Blotched Skate (Notoraja sticta) has only been found on the Great Australian Bight continental slope off South Australia. Its depth range is approximately 820–1,200 m, however the benthic habitats of Australasia below 1,400 m have not been adequately sampled and new depth records might emerge when the deepwater ichthyofauna is surveyed. Commercial fisheries have operated within this species’ range, however, most waters deeper than 700 m off South Australia have been closed since 2007 to protect Orange Roughy (Hoplostethus atlanticus). Prior to the closure, deepwater areas were heavily fished for Orange Roughy and the levels of bycatch during this period were largely unreported. While there are some questions as to the level of affect this fishery had on bycatch species such as this skate, fisheries targeting Orange Roughy generally fish on seamounts and have a low level of bycatch when compared to other fisheries. Given the present closure of fishing within the species' range, it is assessed as Least Concern.

Previously published Red List assessments:
2011 Least Concern (LC)

Geographic Range [top]

Range Description: The Blotched Skate is known only from the mid-continental slope of the Great Australian Bight, South Australia (33°30′S, 130°24′E to 35°10′S, 133°46′E) (McEachran and Last 2008, Last and Stevens 2009).
Countries occurrence:
Australia (South Australia)
FAO Marine Fishing Areas:
Indian Ocean – eastern
Lower depth limit (metres): 1200
Upper depth limit (metres): 820
Range Map: Click here to open the map viewer and explore range.

Population [top]


This skate is known from a handful of specimens but probably occurs more widely throughout southern Australian waters. There are no details available on population size, structure, or trends.

Current Population Trend: Unknown
Additional data:

Habitat and Ecology [top]

Habitat and Ecology: This species occurs on the continental slope at a depth range of approximately 820–1,200 m (McEachran and Last 2008, Last and Stevens 2009). However, the benthic habitats of Australasia below 1,400 m depth have not been adequately sampled and new depth records will doubtless emerge when the deepwater ichthyofauna is surveyed (Last and Yearsley 2002). It attains at least 63 cm total length (TL), with males maturing at about 52 cm TL (McEachran and Last 2008).
Systems: Marine

Use and Trade [top]

Use and Trade:

This skate is not known to be traded and when caught as bycatch it is generally discarded at sea.

Threats [top]

Major Threat(s):

This skate was previously taken as bycatch of the Great Australian Bight Trawl Sector (GABTS), one of the four sectors of the Commonwealth managed Southern and Eastern Scalefish and Shark Fishery (SESSF). The GABTS covers an extensive area of southern Australian waters, from Cape Leeuwin in Western Australia to Cape Jervis in South Australia, and out to the edge of the Australian Fishing Zone (AFZ). It includes a continental shelf fishery, operating in depths of 200 m or less, an upper slope fishery operating at depths of 200–700 m, and a (historical) deepwater fishery at 700-1,000 m (Moore and Curtotti 2014). 

The latter was a seasonal deepwater slope fishery operating at depths greater than 700 m targeting Orange Roughy (Hoplostethus atlanticus) (Knuckey and Brown 2002). However, this fishery was closed in 2007 due to the unsustainability of Orange Roughy stocks. Bycatch in the Orange Roughy fishery has been reported as less than in many other trawl fisheries since aggregations around seamounts are primarily targeted. This is supported by the results of a bycatch survey in the deepwater trawl fishery in the Great Australian Bight Far West Zone with up to 99.6% being the target species, Orange Roughy (Knuckey and Brown 2002).

Conservation Actions [top]

Conservation Actions:

No conservation actions are currently in place for this species. Given that its depth range is 820–1,200 m, with the closure of most areas >700 m depth to trawling (Moore and Curtotti 2014), there is no need for further management measures at this time.

Further research is required on this species’ biology, occurrence, population trends, and capture in fisheries. Given the narrow geographic and depth range, and that the species is likely to be affected if deepwater trawling were to reopen, the status of these fisheries needs to be monitored.

Citation: Beckmann, C. & Huveneers, C. 2015. Notoraja sticta. The IUCN Red List of Threatened Species 2015: e.T195468A68637552. . Downloaded on 28 November 2015.
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