|Scientific Name:||Hydrolagus ogilbyi (Waite, 1898)|
Chimaera ogilbyi Waite, 1898
Hydrolagus waitei Fowler, 1907
|Taxonomic Source(s):||Eschmeyer, W.N., Fricke, R. and Van der Laan, R. (eds). 2016. Catalog of Fishes: genera, species, references. Updated 31 March 2016. Available at: http://researcharchive.calacademy.org/research/ichthyology/catalog/fishcatmain.asp. (Accessed: 31 March 2016).|
|Taxonomic Notes:||Synonym = Hydrolagus (Psychichthys) waitei Fowler, 1908.
This species looks very similar to Hydrolagus lemures and partly overlaps in range although H. ogilbyi is reported to occur in shallower waters and may grow to larger sizes (Last and Stevens 1994). However, data from the study of large collections of H. lemures and H. ogilbyi indicate a much larger overlap in range, both geographic and bathymetric, and size than indicated by Last and Stevens (1994). If H. ogilbyi is indeed restricted in range as indicated by Last and Stevens (1994, 2009), then the large number of records of H. ogilbyi from the Great Australian Bight and Western Australia may be misidentifications. Colour is a primary feature for identification, however it appears to be quite variable within both species and these two species are easily mistaken. Due to the confusion with regard to identification of H. ogilbyi and H. lemures, a closer examination these two species is recommended to determine species distinctions.
Reference to H. ogilbyi from Japan (Tanaka 1908) is probably erroneous and likely a misidentification of Chimaera phantasma.
|Red List Category & Criteria:||Vulnerable A2bd ver 3.1|
|Assessor(s):||Rigby, C.L., Dagit, D.D. & Kyne, P.M.|
|Reviewer(s):||Lawson, J. & Dulvy, N.K.|
|Facilitator/Compiler(s):||Kyne, P.M., Walls, R.H.L., Simpfendorfer, C. & Chin, A.|
Ogilby's Ghostshark (Hydrolagus ogilbyi) is endemic to Australia with a range apparently restricted to southeastern Australia including New South Wales, Tasmania and South Australia, although collection records indicate a possible wider range including northern New South Wales, the Great Australian Bight and perhaps parts of Western Australia. It is typically found on the continental shelf and upper slope at depths of 120-350 m. The species is reported as apparently relatively common to abundant in parts of its range, but confirmation of taxonomic distinction between Ogilby's Ghostshark and Blackfin Ghostshark (H. lemures) is needed to better define distribution. Fishery independent surveys on the New South Wales upper slope have documented significant declines (>99.9% over three generations) in the catch rate of 'silver ghostsharks' as a result of intensive trawl fishing on the narrow New South Wales continental slope. The 'silver ghostsharks' were documented as mostly Ogilby's Ghostshark. This area of New South Wales and the area that continues to be fished are estimated to represent 50% of the current known range of Ogilby’s Ghostshark. Although, as stated above, confirmation of records from outside this known range is required to better define the distribution. Given the steep documented declines in some areas which highlight the susceptibility of Hydrolagus species to trawling and continued fishing over approximately 50% of its range, Ogilby's Ghostshark is assessed as Vulnerable. This assessment should be revised when there is a better understanding of this species' range and taxonomic distinction from the Blackfin Ghostshark.
|Previously published Red List assessments:|
|Range Description:||Ogilby's Ghostshark is an Australian endemic restricted to New South Wales, Victoria, Tasmania and eastern South Australia (Last and Stevens 2009), though it appears to be more widespread based on surveys and data from voucher specimens in museum collections. To the west these collections indicate a much wider range extending into the Great Australian Bight and parts of Western Australia. Along the east coast it has been recorded north of Coffs Harbour to the Queensland border (K. Graham, the Australian Museum, pers. comm., 2006)|
Native:Australia (New South Wales, South Australia, Tasmania, Victoria)
|FAO Marine Fishing Areas:|
Indian Ocean – eastern; Pacific – southwest
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||Ogilby's Ghostshark consists of a single endemic population within Australia. It is reported to be fairly common and relatively abundant, particularly off Tasmania.|
Significant declines in the catch of 'silver ghostsharks' from 1976-77 to 1996-97 from the upper slope trawl fishery off New South Wales have been documented by fishery-independent surveys (Graham et al. 2001). Graham et al. (2001) stated that 'silver ghostsharks' were identified as Ogilby's Ghostshark. Sampling for this study occurred in 200-605 m and so it is likely both Ogilby's Ghostshark (which occurs at 120-350 and possibly 40-524 m) and the related Blackfin Ghostshark (H. lemures) (which occurs at 190-825 m) were captured, however the bulk of catches did appear to be Ogilby's Ghostshark (K. Graham, the Australian Museum, pers. comm., 2003). The aggregated data does not allow species-specific declines to be elucidated, however, overall 'silver ghostshark' declined from a mean catch rate of 8.3 kg/hour to 0.3 kg/hour in the 20 year period, which is an annual rate of decline of 14.9%, equivalent to a 99.9% decline over three generation spans (56 years). If, as it appears, the majority of the catch was Ogilby's Ghostshark, this represents drastic declines. The relatively narrow continental slope off central/southern New South Wales, including most of the depth range of Ogilby's Ghostshark, continues to be fished (Georgeson et al. 2014). However, more recent standardized catch-per-unit-effort by depth exhibited no trend for either Blackfin Ghostshark or Ogilby's Ghostshark between 1994-2006 (Walker and Gason 2007). This suggests that the population may have stabilized at low levels due to changes in fisheries management.
There are regions of the species' range, however, that receive little fishing pressure. If the species extends to the Queensland border, fishing is not as intense on the slope in that area. Indeed, there is little outer shelf/upper slope trawling north of Port Stephens, New South Wales (K. Graham, the Australian Museum, pers. comm., 2003). Furthermore, there are significant areas of the outer shelf off western Victoria, which may serve as a refuge from trawling due to rough bottoms. Some areas off Tasmania also receive little fishing pressure. Based on the current known distribution of Ogilby's Ghostshark it is estimated that the area of the recorded steep population declines and the area within its range that continues to be fished represents approximately 50% of its known range.
|Current Population Trend:||Stable|
|Habitat and Ecology:||Ogilby's Ghostshark is a continental shelf and upper slope dweller occurring in depths of 120 to 350 m (with a possibly wider depth range of 40 to 524 m) on or near the bottom. It attains at least 85 cm (without the caudal filament), 102 cm (with the filament) with males and females mature at about 64-70 cm (without the filament; Last and Stevens 2009). Little else is known of the biology and habits. A generation length of 18.6 years can be estimated from the Rabbitfish (Chimaera monstrosa), which reaches a similar maximum size (Calis et al. 2005).|
|Generation Length (years):||18.6|
|Use and Trade:||The flesh of Ogilby's Ghostshark is of good quality and small quantities are marketed (Last and Stevens 2009).|
|Major Threat(s):||A large proportion of the known range of Ogilby's Ghostshark has been subject to considerable trawling pressure. Within the Southern and Eastern Scalefish and Shark Fishery (SESSF), Ogilby's Ghostshark is considered to have a high catch susceptibility to otter trawl, a medium catch susceptibility to auto hook gear and a low susceptibility to shark gillnet, shark hook and trap/pot gear (catch susceptibility is defined as 'availability' x 'encounterability' x 'selectivity' x 'post-capture mortality'; Walker et al. 2008). Logbook data from the Great Australian Bight Trawl Sector (GABTS) of the SESSF in the late 1990s records Ogilby's Ghostshark catches of 90-360 kg per annum (Rose and McLoughlin 2001). The distribution of trawling in the GABTS is across a very small area with most of the effort in the fishery concentrated on the upper continental shelf and slope, in depths ranging from 100 to 400 metres (AFMA 2014). It is managed by limited entry with 10 fishing concessions and the overall effort is low (Lynch and Garvey 2003). An Ecological Risk Assessment of the Fishery identified the related species, Blackfin Ghostshark (H. lemures) as at low risk in the fishery, though there was no mention of Ogilby's Ghostshark (AFMA 2008). Improved information on the catches of Ogilby's Ghostshark in the GABTS should be available in the future as the 2014-2016 Bycatch and Discarding Working Plan for this fishery states that Integrated Scientific Monitoring Program is to include reporting of chondrichthyan catches at species level to enable a time series of catch to be constructed (AFMA 2014).|
|Conservation Actions:||There are no known conservation measures specific to this species. Detailed comparative study of Ogilby's Ghostshark and Blackfin Ghostshark is recommended to verify the distinction between these two species. Further study of life history characteristics as well as geographic and depth range parameters is also recommended. A continued effort should be made to gain bycatch information in fisheries within the range of this species.|
|Citation:||Rigby, C.L., Dagit, D.D. & Kyne, P.M. 2016. Hydrolagus ogilbyi. The IUCN Red List of Threatened Species 2016: e.T60195A68630008.Downloaded on 24 January 2018.|
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