|Scientific Name:||Deania quadrispinosa (McCulloch, 1915)|
Acanthidium quadrispinosum McCulloch, 1915
|Red List Category & Criteria:||Near Threatened ver 3.1|
|Assessor(s):||Ebert, D.A. & Valenti, S.V.|
|Reviewer(s):||Cavanagh, R.D., Stevens, J. & Fowler, S.L. (Shark Red List Authority)|
Longsnout Dogfish (Deania quadrispinosa) is a poorly known deepwater species reported from the southeast Atlantic, western Indian Ocean, and the western central and southwest Pacific. It is found on the outer continental shelves, upper and middle slopes and off seamounts at depths of 150-1,360 m. Logbook data and the results of fishery-independent surveys document significant declines in several species, including a >80% decline in Longsnout Dogfish over 20 years on the New South Wales slope, Australia (total catch declined from 3,849 kg in 1976/77 to 216 kg in 1996/97). Deepwater fisheries are rapidly expanding in some parts of the species' range. The dramatic declines observed off Australia indicate that this species is vulnerable to rapid population depletion where it is heavily fished. The species is assessed as Near Threatened on the basis of a decline estimated to approach 30% in the global population (close to meeting the criteria for VU A4bd). This reflects significant observed population declines in areas where the species is heavily fished, potential future population declines as fisheries expand in other areas of the range, as well as areas of refuge from fishing pressure at the deeper extent of its depth range. Expansion of deepwater fishing within this species' range should be monitored and the species may qualify for a threatened category in the future if fisheries continue to expand across its range.
|Range Description:||Southeast Atlantic: Namibia, South Africa (Northern and Western Provinces). Western Indian Ocean: South Africa (Eastern Cape Province), southern Mozambique, Madagascar range of seamounts south of Madagascar and east of South Africa. Western central and southwest Pacific: Australia (Western Australia, South Australia, Victoria, Tasmania, New South Wales and Southern Queensland), New Zealand, deepwater between New Zealand, Queensland and New Caledonia, Norfolk Island, Loyaute Island and Vanatu Island (Compagno in prep.).|
Native:Australia (New South Wales, Queensland, South Australia, Tasmania, Victoria, Western Australia); Madagascar; Mozambique; Namibia; New Caledonia; New Zealand; Norfolk Island; South Africa (Eastern Cape Province, Northern Cape Province, North-West Province, Western Cape); Vanuatu
|FAO Marine Fishing Areas:|
Atlantic – southeast; Indian Ocean – western; Pacific – southwest; Pacific – western central
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||This species does not appear to be as common as other birdbeak dogfish.|
Research surveys on the New South Wales slope over a 20 year period have shown a decline from 15.7 to 1.4 kg/h for Deania quadrispinosa (representing a decline of 87.3%) (Graham et al. 1997).
Apparently rare to very rare in New Zealand waters (M. Francis, NIWA, Wellington, pers. comm. 2006).
|Current Population Trend:||Unknown|
|Habitat and Ecology:||A little-known deepwater bottom-dwelling dogfish of the outer continental shelves and upper and middle slopes and off seamounts at depths of 150-1,360 m, with most records on the slopes below 400 m (Compagno in prep.). Last and Stevens (1994) report that this species is common at depths of 400-820 m off Australia. Maximum total length (TL) is about 118 cm for females and 96 cm for males. Size at maturity is 80-90 cm TL for males and 85-100 cm TL for females (Daley et al. 2002, Kyne and Simpfendorfer 2007). Size at birth is ~25 cm TL, with litters of 5-17 (average 10) pups (Daley et al. 2002, Kyne and Simpfendorfer 2007). Deania species have an extended gestation period, probably with a two or three year reproductive cycle that is non-continuous (i.e., with a resting period between parturition and the development of new oocytes) (Daley et al. 2002, Kyne and Simpfendorfer 2007).|
This species is a discarded bycatch of trawl fisheries off South Africa and Australia (Compagno in prep).
Longsnout Dogfish is captured in the Australian Southern and Eastern Scalefish and Shark Fishery (SESSF), which extends across an extensive area of the southern and southeastern Australian Fishing Zone (Kyne and Simpfendorfer 2007). Deepwater fishing on the slope developed off the east coast of Australia (New South Wales) during the 1970s and off southern Australia (Victoria and Tasmania) in the 1980s. Initial catch levels of deepwater sharks off NSW were reportedly high, as were discarding levels as there was no market for deepwater sharks at that time. The development of a market for liver oil (high value), relaxation of regulations on the mercury content of shark flesh and the introduction of a quota management system for target teleost (bony) fishes, lead to the targeting of deepwater dogfishes. Logbook data and the results of fishery-independent surveys document significant declines in several species, including a >80% decline in this species over 20 years on the NSW slope (total catch declined from 3,849 kg in 1976/77 to 216 kg in 1996/97) (Graham et al. 2001).
In the southeastern Atlantic this species has been targeted, along with Centrophorus squamosus and Centroscymnus coelolepis, by an exploratory fishery using set nets off Namibia since 2000. Exploratory licenses granted by the Namibian government to this fishery have been governed by strict management measures, including monitoring and logbook recording of all individuals caught (NATMIRC 2003, Kyne and Simpfendorfer 2007). Data collected during three trips from January to June 2002 on one licensed exploratory vessel showed that 15.8 t of trunks, 9 t of fillets and 11.8 t of livers from D. quadrispinosa were landed, compared to 131.3 t of trunks and 4.5 t of fins from C. squamosus (NATMIRC 2003, Kyne and Simpfendorfer 2007). The exploratory directed deepwater licenses expired in January 2006. The species is also taken as bycatch by the Namibian non-directed trawl fishery at depths of 400-1,000 m, however species specific catch data are not available (NATMIRC 2003, Kyne and Simpfendorfer 2007).
Information on deepwater fisheries throughout other areas of the species' range is limited, however, there is evidence that deepwater fishing pressure is rapidly expanding and increasing in some areas. For example, deep water fisheries targeting fish and deepwater shrimp are expanding off Madagascar; since these deepwater fisheries were authorized in 2001, catch of deepwater fish reached 4,157 tonnes in 2002 (Soumy 2004). Low fecundity may make this species vulnerable to overfishing (Compagno in prep.).
The Australian Fisheries Management Authority (AFMA) has introduced several management measures for deepwater sharks within the SESSF in recent years, which may benefit this species. These include:
|Citation:||Ebert, D.A. & Valenti, S.V. 2009. Deania quadrispinosa. The IUCN Red List of Threatened Species 2009: e.T161635A5469573.Downloaded on 19 September 2017.|
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