|Scientific Name:||Hydrolagus homonycteris|
|Species Authority:||Didier, 2008|
|Taxonomic Notes:||The Black Ghostshark (Hydrolagus homonycteris) is probably closely related to Abyssal Ghostshark (H. trolli), but the two differ in that the Black Ghostshark has a longer dorsal spine, smaller claspers and is darker in colour.|
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor(s):||Theiss, S.M., Huveneers, C. & Ebert, D.A.|
|Reviewer(s):||Walls, R.H.L. & Kyne, P.M.|
|Facilitator/Compiler(s):||Kyne, P.M. & Walls, R.H.L.|
The Black Ghostshark (Hydrolagus homonycteris) occurs along continental slopes and seamounts at depths of 870–1,450 m off southern Australia and at 500–1,400 m off New Zealand. Due to an overlap in habitat, depth and range, it has been a bycatch of benthic deepwater commercial trawl fisheries. This ghostshark was once commonly caught in fisheries targeting Orange Roughy (Hoplostethus atlanticus) off Tasmania, but this fishery has since been closed. As its depth range falls outside the reach of existing deepwater fisheries overlapping with its geographic range, it can be assumed that catch levels are very low or nonexistent. This species is therefore assessed as Least Concern.
|Previously published Red List assessments:|
|Range Description:||The Black Ghostshark occurs off the southern coast of Australia from Portland, Victoria (~38°53'S, 141°56'E) to Ulladulla, New South Wales (~35°21'S, 150°28'E), including the waters surrounding Tasmania and its southern seamounts (Didier 2008, Last and Stevens 2009). This species is also known from deepwater commercial fishing areas off New Zealand and is most likely widespread throughout the deeper waters of New Zealand (Didier 2008).|
Native:Australia (New South Wales, Tasmania, Victoria); New Zealand (North Is., South Is.)
|FAO Marine Fishing Areas:|
Indian Ocean – eastern; Pacific – southwest
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||This species is apparently common, however there are no details on population size, structure or trends.|
|Current Population Trend:||Unknown|
|Habitat and Ecology:|
This ghostshark is found along the continental slope and seamounts at depths of 870–1,450 m off southern Australia and 500–1,400 m off New Zealand (Didier 2008, Walker et al. 2008, Last and Stevens 2009). It reaches a maximum size of at least 108 cm total length and 66 cm body length (BDL), with males maturing at about 55 cm BDL and females around 60 cm BDL (Didier 2008). Like other members of this family, it is oviparous (unpublished data reported in Walker et al. 2008).
|Use and Trade:||
The flesh of the Black Ghostshark is of good edible quality. It was at one time commonly taken by commercial trawlers targeting Orange Roughy (Hoplostethus atlanticus) in the waters surrounding Tasmania, but is not currently as this fishery closed in 2007 (Last and Stevens 2009, Patterson and Mazur 2014). This species is also documented from deepwater fisheries off New Zealand but information regarding potential use in this country is not available.
This ghostshark is an infrequent bycatch of benthic deepwater trawl fisheries. Within Australian waters the threat from fisheries is likely to be very low or nonexistent following the closure of the South Tasman Rise Fishery (STRF) in 2007 (Patterson and Mazur 2014). If this fishery were to re-open, it could pose a risk to the Australian part of the population. It has also been reported as rare bycatch from the Southern and Eastern Scalefish and Shark Fishery (SESSF) (Walker et al. 2008), although most of the area of this fishery below 700 m depth is closed to fishing (Georgeson et al. 2014).
The Black Ghostshark is a bycatch of New Zealand deepwater trawl and longline fisheries; the bycatch trend increased slightly in the ling longline fishery between 1990-91 and 2010-11 (MFI 2103).
No species-specific conservation measures are currently in place and information regarding its biology is required. There are Commonwealth marine reserves within its Australian range, and the closure of the STRF and depth limit on the SESSF should serve to protect this species from capture in these waters as well. Monitoring is recommended with regard to these fisheries re-opening or expanding in future.
|Citation:||Theiss, S.M., Huveneers, C. & Ebert, D.A. 2015. Hydrolagus homonycteris. The IUCN Red List of Threatened Species 2015: e.T195433A68629582.Downloaded on 20 January 2017.|
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