|Scientific Name:||Hydrolagus trolli|
|Species Authority:||Didier & Séret, 2002|
|Taxonomic Notes:||Synonyms = Hydrolagus sp. C Paulin et al., 1989; Hydrolagus sp. cf lemurs Séret in Grandperrin et al., 1997; Hydrolagus sp. Séret in Grandperrin et al., 1999.
A recently described, highly distinctive species, Hydrolagus trolli is often caught with a species of giant black chimaera (cf. Hydrolagus affinis), and the range of these two species may overlap in some areas, but H. trolli is readily separated by its distinctive blue colouration and more acute snout.
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor(s):||Compagno, L.J.V. & Dagit, D.D.|
|Reviewer(s):||Walls, R.H.L. & Kyne, P.M.|
|Facilitator/Compiler(s):||Kyne, P.M. & Walls, R.H.L.|
The Abyssal Ghostshark (Hydrolagus trolli) is a large deepwater ghostshark (probably up to 120 cm total length) which may have a widespread distribution in the Southern Ocean and may be moderately common in New Zealand waters, but rare in other regions. It has been recorded on deep continental and insular slopes at depths of 610 to 2,000 m, mostly below 1,000 m. While this species may be an uncommon bycatch of deepwater fisheries operating within its geographic range, its depth range extends far beyond the reach of existing fisheries, offering it refuge from exploitation. It is therefore assessed as Least Concern.
|Previously published Red List assessments:||
|Range Description:||The Abyssal Ghostshark was originally described from deepwater off New Zealand and New Caledonia. More recently, there have been infrequent captures of this species from deepwater seamounts in the Southern Ocean including off southern Australia (Victoria), Lord Howe Rise and Norfok Ridge (Last and Stevens 2009). It may be wide-ranging in the Southern Ocean. References to the species off southern Africa refer to a distinct undescribed species (D. Ebert, pers. com., 2015).|
Native:Australia; New Caledonia; New Zealand
|FAO Marine Fishing Areas:||
Pacific – southwest; Pacific – western central
|Lower depth limit (metres):||2000|
|Upper depth limit (metres):||610|
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||Nothing is known of population size or structure. Appears to be more common around New Zealand and rarer in other parts of its range, but this may only be a reflection of fishing/survey effort. Future research may provide evidence that separate populations exist across the range of this species.|
|Current Population Trend:||Unknown|
|Habitat and Ecology:||The Abyssal Ghostshark occurs on deep continental and insular slopes at depths of 610-1,700 m off New Zealand and New Caledonia and 1,670-2,000 m off Victoria, Australia, but mostly collected below 1,000 m. This species is oviparous. Size at maturity is ~55 cm body length (BDL) in females and ~60 to 65 cm BDL in males. Recorded maximum size is 111 cm total length (TL), 91 cm BDL, and the maximum attainable size is probably ~120 cm TL.
|Use and Trade:||This species is not known to be of commercial value.|
|Major Threat(s):||Common on deepwater fishing grounds off New Zealand where it is an incidental capture in deepwater benthic trawls (MPI 2013). May possibly be a bycatch of deepwater fishing off southern Australia, although most areas below 700 m depth are closed to trawling (Georgeson et al. 2014). Illegal fishing activities, particularly for Patagonian Toothfish (Dissostichus eleginoides), are likely taking this species, although it can be assumed that catch rates in all of these fisheries are low given the depth range of this species, which extends far below the reach of deepwater fisheries, offering it refuge from exploitation.|
|Conservation Actions:||More information is required of bycatch levels from the teleost fisheries which overlap with the range of this species. More specimens, particularly juveniles are needed, as is life history data. Most areas below 700 m depth off southern Australia are closed to trawling (Georgeson et al. 2014) and the species may occur in some protected areas of the Commonwealth Marine Reserve network off southern Australia.|
|Citation:||Compagno, L.J.V. & Dagit, D.D. 2015. Hydrolagus trolli. The IUCN Red List of Threatened Species 2015: e.T60197A70709551. . Downloaded on 29 November 2015.|
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