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Squalus chloroculus

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA CHONDRICHTHYES SQUALIFORMES SQUALIDAE

Scientific Name: Squalus chloroculus
Species Authority: Last, White & Motomura, 2007
Common Name(s):
English Greeneye Spurdog
Taxonomic Notes: Recent revision of Squalus in the Indo-Australian region resulted in the resurrection of S. montalbani (Philippines, Indonesia, Australia) and S. griffini (New Zealand) and the description of S. chloroculus Last, White & Motomura, 2007. These species were previously considered to be con-specific with S. mitsukurii, which this work has revealed, does not occur in Australasian waters. Further investigation of Squalus mitsukurii from around the world will likely result in more taxa being recognized.

Assessment Information [top]

Red List Category & Criteria: Near Threatened ver 3.1
Year Published: 2009
Date Assessed: 2008-12-01
Assessor(s): Valenti, S.V., Stevens, J.D. & White, W.T.
Reviewer(s): Fowler, S.L. & Gibson, C.G. (Shark Red List Authority)
Justification:
The Greeneye Spurdog (Squalus chloroculus) is a large, recently described dogfish only known from New South Wales to the Great Australian Bight, southern Australia at depths of 216–1,360 m. This species was previously considered to be conspecific with Shortspine Spurdog (S. mitsukurii), however recent taxonomic work has revealed that the latter species does not occur in Australasian waters. Documented declines of approximately 97% of ‘Greeneye Dogsharks’ between 1976–77 and 1996–97 off central to southern New South Wales were reported from a fishery independent survey. Fishing pressure is intensive on these trawl grounds, where there is evidence that this species has been severely depleted. However, the rest of the species’ deepwater range throughout southern Australia to the Great Australian Bight is relatively lightly fished. The species’ depth range extends to 1,360 m depth, affording it refuge from fishing pressure at the lower extent of its range (particularly now that the fishery has been closed below 700 m). Thus S. chloroculus is assessed as Near Threatened globally, on the basis of an overall past decline in the total population estimated at 30–50%, reflecting its wider distribution outside the heavily fished area. Efforts should be made to monitor the population, particularly given the inherent biological vulnerability typical of Squalid sharks (three generation period may approach ~70 years). If fishing pressure increased further across this species range it would need to be re-evaluated.

Geographic Range [top]

Range Description: Eastern Indian Ocean and southwest Pacific: upper to mid continental slope off southern Australia from New South Wales (ca. 35°S) to the Great Australian Bight (33°S, 129°E).
Countries:
Native:
Australia (New South Wales, South Australia)
FAO Marine Fishing Areas:
Native:
Indian Ocean – eastern; Pacific – southwest
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: A recently described species (Last et al. 2007). The description provides details on the holotype and 14 additional specimens.

Documented declines of approximately 97% of ‘greeneye dogsharks’ between 1976-77 and 1996–97 between the Sydney area (central NSW) and the Eden-Gabo Island area (southern NSW/northern Victoria) were reported from a fishery independent survey (Graham et al. 2001). Total catches in the abovementioned areas at depths of 220 to 605 m declined from a mean of 44.8 kg/h in 1976/77 to a mean of 1.2 kg/h in 1996-97 (Graham et al. 2001). It is likely that Squalus chloroculus, S. montalbani and S. grahami were all caught during these surveys (K. Graham pers. comm. 2007). Squalus chloroculus was possibly the predominant species in the southern survey areas (Ulladulla and Eden-Gabo Island) (K. Graham pers. comm. 2007).
Population Trend: Unknown

Habitat and Ecology [top]

Habitat and Ecology: Found on upper to mid continental slopes at depths of 216–1,360 m (Last et al. 2007). Females and males reach at least 83.2 cm total length (TL) and 85.6 cm TL respectively (Last et al. 2007). Males mature by 68.5 cm TL (Last et al. 2007).
Systems: Marine

Threats [top]

Major Threat(s): Documented declines in fishery-independent scientific surveys for this species, and two other dogfishes, show that they are vulnerable to rapid population decline where they are heavily fished (see Population section above). Fishing pressure is intensive on trawl grounds around south-east Australia, where there is evidence that this species has been severely depleted. However the rest of the species’ deepwater range throughout southern Australia to the Great Australian Bight (representing about three quarters of the species’ total range) is relatively lightly fished, by comparison. The species’ depth range extends to 1,360 m depth, affording it some refuge from fishing pressure at the lower extent of its range (particularly now that the fishery has been closed below 700 m).

Conservation Actions [top]

Conservation Actions: There are no species-specific measures in place for this species. The Australian Fisheries Management Authority (AFMA) has, however, introduced the following general measures for deepwater sharks within the Australian Southern and Eastern Scalefish and Shark Fishery (SESSF) in recent years, which may benefit this species:

Since 2003, vessels are required to land both the livers and carcasses of all dogfishes to enable accurate landing information to be recorded.

Since 2007, SESS Fishery was closed below 700 m to prevent targeting of deepwater species (750 m in Great Australian Bight Fishery) (See: http://www.mffc.gov.au/releases/2007/07005a.html).

Citation: Valenti, S.V., Stevens, J.D. & White, W.T. 2009. Squalus chloroculus. The IUCN Red List of Threatened Species. Version 2014.3. <www.iucnredlist.org>. Downloaded on 26 November 2014.
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