|Scientific Name:||Centrophorus uyato|
|Species Authority:||(Rafinesque, 1810)|
Squalus uyato Rafinesque, 1810
|Taxonomic Notes:||Eschmeyer notes that this is valid as Centrophorus uyato (Rafinesque 1810), but also that its status is uncertain. The species C. uyato does not appear in Leonard Compagno's taxonomic checklist (in press - March 2004).
The taxonomy of C. uyato has not been adequately resolved and the Australian populations may be distinct from those outside of Australia (J. Stevens, pers. comm., Daley et al. 2002).
|Red List Category & Criteria:||Data Deficient ver 3.1|
|Assessor(s):||Pogonoski, J. & Pollard, D. (SSG Australia & Oceania Regional Workshop, March 2003)|
|Reviewer(s):||Cavanagh, R.D., McAuley, R. (Shark Red List Authority) & Graham, K.|
Declines of over 99% between the years 1976 to 1977 and 1996 to 1997 between the Sydney area (central New South Wales) and the Eden-Gabo Island area (southern New South Wales/northern Victoria) have been documented by a fishery independent trawl survey. The relatively narrow continental slope habitat of this species (which is fished throughout its entire depth range) suggests that it may now only be present in any numbers in areas that are non-trawlable. However, as dropline fishers also harvest this species off New South Wales (under NSW jurisdiction), further pressure may be placed on it in such areas. There was a small, short-lived fishery out of Esperance, Western Australia for C. uyato in the mid-1990s, which ceased due to rapid catch declines and there may be some bycatch in the Western Australia Commonwealth-managed trawl fishery. As with other deepwater sharks, particularly this genus, the low fecundity, high longevity and probable late age at first maturity of this species not only result in extremely rapid population depletion in fisheries, but also prevent it from quick recovery after such depletion.
This species is currently Data Deficient globally due to the taxonomic problems. However, deepwater demersal trawl fisheries are expanding in other parts of its potential range, and with the observed declines described above, together with the knowledge that its biology is similar to other deepwater shark species, this, and related species warrants urgent conservation attention globally
|Range Description:||Ranges from Meditteranean and Black Sea, Atlantic, Indian Ocean, and southwest Pacific. Australian populations may be taxonomically distinct from those elsewhere. Australian populations are documented as being from Esperance to Geraldton (Western Australia) and Fowlers Bay (South Austrlia) to Port Stephens (New South Wales), including Tasmania (Last and Stevens 1994), but further study of this distribution is necessary given the taxonomic problems in this genus (J. Stevens CSIRO, pers. comm., Daley et al. 2002).|
Native:Angola (Angola); Australia (New South Wales, South Australia, Tasmania, Victoria, Western Australia); Cameroon; Mozambique; Namibia; Nigeria; Portugal; Senegal; Taiwan, Province of China; United States
|FAO Marine Fishing Areas:|
Atlantic – eastern central; Atlantic – western central; Atlantic – northeast; Atlantic – southeast; Indian Ocean – western; Indian Ocean – eastern; Mediterranean and Black Sea; Pacific – southwest
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||The population size (although suspected to be much reduced) and number and size of subpopulations are unknown.|
|Current Population Trend:||Unknown|
|Habitat and Ecology:||Demersal on the continental shelf and upper-middle continental slope in depths of 50 to 1,400 m. In Australia, main depth range is 400 to 650 m (Last and Stevens 1994), but has been recorded from 220 to 740 m (Graham et al. 1997). Ovoviviparous, usually producing one pup. The diet consists of bony fishes and cephalopods (Last and Stevens 1994), but also includes crustaceans (Daley et al. 2002). Length at first maturity is 80 cm for males (Last and Stevens 1994) and 100 cm for females (Daley et al. 2002). Size at birth is 35-45 cm (Last and Stevens 1994, Daley et al. 2002). |
Preliminary ageing studies by Fenton (2001) suggest that C. uyato lives to at least 46 years of age (n=8). The low fecundity, high longevity and probable late age at first maturity of this species prevent it from quick recovery after sustained fishing of its populations in the last 20 to 30 years (Graham et al. 2001, Daley et al. 2002).
1) Targeted fishing using deep set gillnets off South Australia and eastern Victoria in the Southern Shark Fishery. This targeting had all but ceased by 1995 because of declining catches (Daley et al. 2002).
2) Demersal trawling (South East Trawl Fishery, SETF) in New South Wales and eastern Victoria (Daley et al. 2002). Declines of over 99% have been documented between the years 1976 to 1977 and 1996 to 1997 between the Sydney area (central New South Wales) and the Eden-Gabo I. area (southern New South Wales/northern Victoria) by the trawl research vessel Kapala (fishery independent survey) (Graham et al. 1997, Graham et al. 2001, Andrew et al. 1997). Catches in the abovementioned areas in 220 to 605 m (i.e., most of the preferred depth range of this species) declined from a mean of 106.9 kg/h in 1976 to 1977 to a mean of 0.3 kg/h (a total of only 14 specimens) in 1996-97.
3) Droplining (under New South Wales Fisheries jurisdiction) along the continental slope within its range (although catches are relatively minor).
4) Previously targeted by gillnetting in Western Australia shark fishery (1996-1999). Fishery has since ceased: according to fishers, catch rates began to decline dramatically after 2 to 3 years (R. McAuley Western Australia Fisheries pers. comm. March 2003). Centrophorus dogfishes are marketed for their flesh and liver oil (squalene) (Daley et al. 2002).
Recent (Jan 2003) management changes to the SETF by the Australian Fisheries Management Authority limit the combined catch of Centrophorus dogfishes to a maximum of 150 kg trunked weight per trip. In addition, livers of Centrophorus are not to be retained unless the individual carcasses from which they were obtained are also landed (J. Stevens CSIRO, pers. comm.).
Centrophorus uyato has also been nominated for listing as a Vulnerable species on the Commonwealth Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act). If listed as Vulnerable, the EPBC Act requires that a Recovery Plan be put in place within a five year period (Sara Williams, Environment Australia, pers. comm.).
|Citation:||Pogonoski, J. & Pollard, D. (SSG Australia & Oceania Regional Workshop, March 2003). 2003. Centrophorus uyato. The IUCN Red List of Threatened Species 2003: e.T41745A10552606.Downloaded on 05 December 2016.|
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