|Scientific Name:||Etmopterus unicolor|
|Species Authority:||(Engelhardt, 1912)|
Etmopterus compagnoi Fricke & Koch, 1990
Spinax unicolor Engelhardt, 1912
|Taxonomic Notes:||The taxonomic history of Etmopterus unicolor is complex. This species has been confused with E. spinax, which does not occur in South African waters and E. gracilispinis which does occur in South African waters (Compagno in prep). Etmopterus compagnoi is tentatively ranked as a junior synonym of E. unicolor based on Fricke and Koch’s (1990) description (Compagno in prep). E. tasmaniensis Myagkov & Pavlov, 1986 is a questionably valid species that may be based on this species or E. baxteri. Formerly known as E. sp. B off Australia (Compagno et al. 2005).|
|Red List Category & Criteria:||Data Deficient ver 3.1|
|Assessor(s):||McCormack, C. & Valenti, S.V.|
|Reviewer(s):||Ebert, D.A., Stevens, J. & Francis, M. (Shark Red List Authority)|
The Bristled Lanternshark (Etmopterus unicolor) is a deepwater lantern shark found on continental and insular slopes, often at the bottom and sometimes well off it, at depths of 402–1,380 m. Known from the western and southern coasts of South Africa, southern Australia, Namibia and Japan. This species probably has limiting life-history characteristics, like other deepwater squalid sharks (preliminary age data show that similar species mature at 11.5–30 years), making it vulnerable to population depletion. It is taken as bycatch of various fisheries throughout its range. It was taken in large quantities off Australia and discarded, but the survival of discards was probably very low. At present there is insufficient information to assess this species beyond Data Deficient; however efforts should be made to quantify bycatch levels to enable reassessment in the near future.
|Range Description:||Southeast Atlantic and western Indian Ocean: Namibia, South Africa (Northern Cape near Hondeklip Bay, Western Cape from Saldanha Bay to Cape Agulhas, Eastern Cape from Plettenberg Bay to Algoa Bay, and northern kwaZulu-Natal) (Compagno in prep).
Eastern Indian Ocean and southwest Pacific: southern Australia (from Perth to in Western Australia to Victoria and Tasmania), seamounts south of Australia including the Cascade Plateau and South Tasman Rise and from New South Wales, north to Taree (Compagno in prep). Yano (1997) recorded E. unicolor from the ridges to the north (Three Kings Ridge and Lord Howe Rise) of New Zealand waters, but further taxonomic study is required to determine whether Northern and Southern Hemisphere populations are con-specific (M. Francis pers. comm. 2007).
Northwest Pacific: Japan (southeastern Honshu) (Compagno in prep).
Native:Australia (New South Wales, South Australia, Tasmania, Western Australia); Japan (Honshu); Namibia; South Africa (Eastern Cape Province, KwaZulu-Natal, Northern Cape Province, Western Cape)
|FAO Marine Fishing Areas:||
Atlantic – southeast; Indian Ocean – eastern; Indian Ocean – western; Pacific – northwest; Pacific – southwest
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||Common off the west and south coasts of South Africa, off southern Australia. In these areas this species is caught with the larger E. baxteri (Compagno in prep). Both species were caught together in 29% of 65 short (half-hour) experimental trawls by research vessels on the slopes at 383–1,300 m off the west and southeast coasts of South Africa. In some instances in sufficient numbers to suggest, but not prove, mixed schools (Compagno in prep). It is known only from a few records on the Three Kings Ridge and Lord Howe Rise, north of New Zealand and has not been recorded within the New Zealand EEZ (Yano 1997, M. Francis pers. comm. 2007).|
|Habitat and Ecology:||
Continental and insular slopes, often at the bottom and sometimes well off it. Found at depths of 402–1,380 m (Compagno et al. 2005). Maximum total length 79 cm total length (TL); size at birth about 17 cm (TL); immature males 23–51 cm (TL), adolescent males 45–51 cm (TL), adult males 48–68 cm (TL); immature females 26–56 cm (TL), adolescent females 37–67 cm (TL), adult females 53–63 cm (TL) (Compagno in prep.).
This species may have similar life-history characteristics to E. baxteri. A recent study by Irvine et al. (2006) on the age and growth of E. baxteri provided unvalidated age estimates for this species. These suggest that females reach maturity between 11.5 and 30 years of age, and males at 10.5–20 years. The lower and upper estimates are based on external growth bands, and internal growth bands, respectively. Although there is a large discrepancy between the preliminary upper and lower estimates, they both suggest that E. baxteri is a long-lived and late maturing species. Etmopterus unicolor may share similar life-history characteristics, making it susceptible to depletion by over-fishing.
|Major Threat(s):||Probably an incidental bycatch of trawl fisheries for Deepwater Hake (Merluccius paradoxus) off the west coast of South Africa, and it used to be caught in deepwater trawl fisheries for Orange Roughy (Hoplostethus atlanticus, Trachichthyidae) off Australia, although these have now been much reduced through quotas and closed areas. It is also caught in the epipelagic zone, at up to 120 m depth, by Japanese longliners in the open ocean near Australia (Compagno in prep.). This species is sometimes caught in large quantities off southern Australia and discarded. However, discarded catch would probably have very low survival rates (J.D. Stevens pers. comm. 2007).|
No specific measures are in place.
Recommended: Bycatch in fisheries should be quantified and population trends monitored. Information is also required on the life-history characteristics.
Restrictions on trawling below 700 m in southern Australia, and basket quotas on deep-water dogfish.
|Citation:||McCormack, C. & Valenti, S.V. 2009. Etmopterus unicolor. The IUCN Red List of Threatened Species. Version 2015.2. <www.iucnredlist.org>. Downloaded on 04 August 2015.|
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