Hypnos monopterygius 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Chondrichthyes Rajiformes Hypnidae

Scientific Name: Hypnos monopterygius (Shaw, 1795)
Common Name(s):
English Coffin Ray, Crampfish, Numbie

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2015
Date Assessed: 2015-02-24
Assessor(s): Jacobsen, I.P. & Lisney, T.J.
Reviewer(s): Dulvy, N.K. & Kyne, P.M.
Contributor(s): Kyne, P.M.
Facilitator/Compiler(s): Kyne, P.M., Walls, R.H.L., Simpfendorfer, C. & Chin, A.
The Coffin Ray (Hypnos monopterygius) occurs widely in warm temperate and tropical Australian waters, but with a gap in its distribution in southeastern Australia. New records over the last decade or so have extended the known range of the species into the Timor Sea (Northern Territory) and the Great Barrier Reef (Queensland). It occurs on sandy and muddy habitats from close inshore mostly to 80 m depth, although it has been recorded to 220 m. This species is occasionally taken as bycatch by commercial trawlers; post-release mortality is likely to be low as it can survive out of water for hours and is usually discarded alive. Further information is required on its life history, and its full distribution off northwestern Australia. It is assessed as Least Concern given that it is common and widely distributed and is of no interest to fisheries.
Previously published Red List assessments:

Geographic Range [top]

Range Description:The Coffin Ray is found in tropical and warm temperate Australian waters from St Vincents Gulf (South Australia) to Timor Reef (Northern Territory), and, from Eden (New South Wales) to at least Heron Island, Great Barrier Reef (Queensland; approximately 23°27′S, 151°55′E) (Kyne et al. 2005, Last and Stevens 2009, G. Johnson, pers. comm., 2015). While the northern extent of the northwestern distribution has previously been reported to Broome, Western Australia (Last and Stevens 2009), at least two specimens have been reported from Timor Reef (Northern Territory) indicating the northwestern distribution of the Coffin Ray extends into the Timor Sea (G. Johnson, pers. comm., 2015). A disjunct exists in this species' range from St Vincents Gulf (South Australia) to Eden (New South Wales) and the species has not been recorded from the waters of Victoria or Tasmania (Last and Stevens 2009).
Countries occurrence:
Australia (New South Wales, Northern Territory, Queensland, South Australia, Western Australia)
FAO Marine Fishing Areas:
Indian Ocean – eastern; Pacific – western central; Pacific – southwest
Additional data:
Lower depth limit (metres):220
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Unknown, although this species is considered to be relatively common in some inshore locations including northern New South Wales (Goldman 2007).
Current Population Trend:Unknown
Additional data:

Habitat and Ecology [top]

Habitat and Ecology:The Coffin Ray is a small, highly distinctive electric ray. This slow-moving species is found in inshore environments, buried on sandy and muddy bottoms. It is more commonly observed in water depths to 80 m, although specimens have been reported to depths of 220 m (Last and Stevens 2009).

This species is viviparous (lecithotrophic) and has litter sizes of 4-8 pups. Size at birth for this species is ~8-11 cm total length (TL) with both sexes maturing at around 40-48 cm TL. Size at first sexual maturity for males and females reported as 42 cm TL and 39.5 cm TL, respectively. Females reach at least 62.5 cm TL; males are marginally smaller reaching at least 55 cm TL (Goldman 2007, Last and Stevens 2009). A very hardy animal, it can survive out of water for hours. Further information is required on this species' reproductive cycle and its age and growth parameters.

Use and Trade [top]

Use and Trade: This species is not known to be utilized and is discarded when caught as bycatch.

Threats [top]

Major Threat(s): The Coffin Ray is caught as bycatch in a number of fisheries, primarily trawl fisheries of eastern and southeastern Australia. The capture of this species by trawlers is, in part, exacerbated by the limited mobility of the species and its behavioral ecology. For example, the Coffin Ray relies heavily on camouflage and the electroplaque organ (electric organ) for defense and for prey capture. As a consequence, individuals in the path of a trawl track are unlikely to move until the net is within the immediate vicinity, therefore increasing the likelihood of them being captured. It is important to note though that the Coffin Ray is a relatively hardy species with the majority of caught individuals being released alive. Given this, post-release survival rates for individuals that have experienced a trawl event are expected to be high.

Catch data for this species is relatively limited and confined to eastern and southeastern Australia. Catch estimates for the Southern and Eastern Scalefish and Shark Fishery (Walker and Gason 2007) indicate that around nine tonnes are caught and subsequently discarded annually. The species has also been reported in limited numbers from the eastern king prawn sector of the Queensland East Coast Otter Trawl Fishery and more regularly from the New South Wales Ocean Trawl Fishery (Courtney et al. 2007, Goldman 2007, Kyne 2008).

Conservation Actions [top]

Conservation Actions: There are currently no conservation measures in place for this species; although it would derive some benefit from fisheries management initiatives like spatial closures and the use of turtle exclusion devices. However, it is unclear how much protection these measures would provide the Coffin Ray in areas with high levels of trawl effort (in particular parts of eastern and southeastern Australia).

Citation: Jacobsen, I.P. & Lisney, T.J. 2015. Hypnos monopterygius. The IUCN Red List of Threatened Species 2015: e.T41828A68630121. . Downloaded on 26 April 2018.
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