Overview

Comprehensive Description

Biology

Found on the continental slope (Ref. 6871, 75154). Presumably ovoviviparous (Ref. 6871). Smallest mature male recorded at 82.5 cm TL (Ref. 76933).
  • Compagno, L.J.V. 1984 FAO Species Catalogue. Vol. 4. Sharks of the world. An annotated and illustrated catalogue of shark species known to date. Part 1 - Hexanchiformes to Lamniformes. FAO Fish. Synop. 125(4/1):1-249. Rome: FAO. (Ref. 247)
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Distribution

Range Description

Harrisson’s Dogfish ranges continuously along the east coast of Australia from southern Queensland (26°40’S) to South East Cape, Tasmania (43°40’S), as well as on the Fraser Seamount off Queensland and Taupo Seamount off New South Wales (NSW) (Graham and Daley 2011). During 2011–2012, the presence of Harrisson’s Dogfish was also confirmed on the Recorder, Britannia, Derwent Hunter and Barcoo Seamounts, establishing its presence on all of the Tasmantid seamounts except for Gascoyne Seamount, the most southern (K. Graham pers. obs.). In February 2012, a specimen caught close to Lord Howe Island was deposited in the Australian Museum, Sydney (Registration No. I.45944-001). Duffy (2007) gives details of single specimens from each of the Kermadec and Three Kings Ridges to the north of New Zealand, and reports nominal records from the northern Norfolk Ridge south of New Caledonia, the Three Kings Ridge and the Wanganella Bank just outside the New Zealand Exclusive Economic Zone (EEZ). Duffy (2007) further states: ‘Collections indicate C. harrissoni is probably continuously distributed along the Norfolk Ridge from 17°30’S to at least 33°S.’
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Eastern Indian Ocean: Western Australia. Southwest Pacific: New South Wales to Tasmania. Recorded in Norfolk Ridge, Three Kings Ridge amd Kermadec Ridge, extending the species eastern range (Ref. 89942). Record from Taiwan uncertain. This species is very close to Centrophorus uyato and may be a junior synonym of that species (Ref. 247).
  • Last, P.R. and J.D. Stevens 1994 Sharks and rays of Australia. CSIRO, Australia. 513 p. (Ref. 6871)
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Australia and New Zealand (possibly New Caledonia).
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Physical Description

Size

Maximum size: 1100 mm TL
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Max. size

111 cm TL (male/unsexed; (Ref. 76933))
  • White, W.T., D.A. Ebert and L.J.V. Compagno 2008 Description of two new species of gulper sharks, genus Centrophorus (Chondrichthyes: Squaliformes: Centrophoridae) from Australia. pp. 1-21. In P.R. Last, W.T. White and J.J. Pogonoski (eds). Descriptions of new Australian chondrichthyans. CSIRO Marine and Atmospheric Research Paper no. 22. 365 p. (Ref. 76933)
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Diagnostic Description

A moderate-sized species distinguished by the following set of adult characters: length of pre-second dorsal 61.9-63.2% TL, 6.6-8.4 times the dorsal-caudal space; length of pre-first dorsal 30.4-32.0% TL; interdorsal space 18.2-20.6% TL, 2.2-2.6 times dorsal-caudal space; dorsal-caudal space 7.5-9.4% TL, 3.2-4.0 in pectoral-pelvic space; long and robust head, its length 22.4-24.6% TL, 2.7-3.0 times mouth width, its width 13.2-14.0% TL, 4.5-4.8 in pre-second dorsal length; width at anterior of nostrils 7.7-7.9% TL; long snout, its preoral length 11.4-12.4% TL, 2.0-2.2 times head height at anterior of mouth, 1.3-1.5 times mouth width, the horizontal preorbital length 7.1-8.2% TL, the horizontal prenarial length 4.4-5.4% TL; large mouth, its width 7.8-8.5% TL; moderately large pectoral fin, its anterior margin 11.9-12.4% TL, 2.3-2.4 times base length; large caudal fin, the dorsal caudal margin 19.1-19.5% TL; 2.1-2.5 times dorsal-caudal space; moderately large and tall first dorsal fin, its height 6.2-7.0% TL, with moderately robust spine, the base width 0.9-1.0% TL. The dorsal fins of juveniles have a distinct blackish oblique blotch anteriorly and a white blotch on the upper posterior margin; in adults a less distinct dark blotch, often apparent in fresh specimens and with a white blotch restricted to a narrow white posterior margin (occasionally indistinct in largest specimens). Adults with flank denticles flat, block-like, not overlapping, and crenulate. Females and immature males with upper teeth that are strongly oblique, similar in shape, but much smaller than lower teeth; in mature males upper teeth are erect, upright, becoming only slightly oblique laterally. 37-39/30 or 31 (n=3) tooth row count; 117-126 (mean 121.6, n=20) total vertebral centra; 53-59 (56.4, n=21) monospondylous precaudal centra; 29-37 (32.7, n=21) diplospondylous precaudal centra; 85-94 (89.1, n=21) precaudal centra (Ref. 76933).
  • White, W.T., D.A. Ebert and L.J.V. Compagno 2008 Description of two new species of gulper sharks, genus Centrophorus (Chondrichthyes: Squaliformes: Centrophoridae) from Australia. pp. 1-21. In P.R. Last, W.T. White and J.J. Pogonoski (eds). Descriptions of new Australian chondrichthyans. CSIRO Marine and Atmospheric Research Paper no. 22. 365 p. (Ref. 76933)
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Ecology

Habitat

Habitat and Ecology

Habitat and Ecology
Graham and Daley (2011) discuss in detail the depth distribution, biology and stock structure of Harrisson’s Dogfish off southeastern Australia. The species inhabits the upper- to mid-continental slope, mainly in depths between 350 and 800 m but with an overall depth range of 275–1,050 m. Although the diet of this species consists mainly of mesopelagic teleost fishes (particularly myctophids), cephalopods and crustaceans, Harrisson’s Dogfish appears to be essentially demersal in habit and is highly vulnerable to demersal trawling and longlining. Maximum size is 112 cm total length (TL), with females mature at ~99 cm TL and males at ~84 cm TL; size at birth is ~35 cm TL (Graham and Daley 2011). It has a very low fecundity of one to two pups every two (or possibly three) years, high longevity (closely related species live for at least 46 years according to preliminary ageing studies by Fenton (2001)) and an estimated age at first maturity (>23 years (Whitely 2004)). Taking these attributes into account, Forrest and Walters (2009) estimated that the annual Maximum Sustainable Yield (MSY) of Gulper Sharks from southeastern Australian waters was in the order of 1%, indicating that any recovery of over-fished stocks would be very slow.

Systems
  • Marine
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Environment

bathydemersal; marine; depth range 250 - 790 m (Ref. 6871)
  • Last, P.R. and J.D. Stevens 1994 Sharks and rays of Australia. CSIRO, Australia. 513 p. (Ref. 6871)
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Depth range based on 33 specimens in 1 taxon.
Water temperature and chemistry ranges based on 32 samples.

Environmental ranges
  Depth range (m): 428 - 818.5
  Temperature range (°C): 5.652 - 11.407
  Nitrate (umol/L): 11.503 - 36.119
  Salinity (PPS): 34.139 - 34.961
  Oxygen (ml/l): 1.950 - 4.837
  Phosphate (umol/l): 0.934 - 2.517
  Silicate (umol/l): 5.526 - 73.648

Graphical representation

Depth range (m): 428 - 818.5

Temperature range (°C): 5.652 - 11.407

Nitrate (umol/L): 11.503 - 36.119

Salinity (PPS): 34.139 - 34.961

Oxygen (ml/l): 1.950 - 4.837

Phosphate (umol/l): 0.934 - 2.517

Silicate (umol/l): 5.526 - 73.648
 
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Depth: 250 - 790m.
From 250 to 790 meters.

Habitat: bathydemersal. Found on the continental slope (Ref. 6871). Presumably ovoviviparous (Ref. 6871).
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Life History and Behavior

Life Cycle

Ovoviviparous, embryos feed solely on yolk (Ref. 50449). Distinct pairing with embrace (Ref. 205).
  • Breder, C.M. and D.E. Rosen 1966 Modes of reproduction in fishes. T.F.H. Publications, Neptune City, New Jersey. 941 p. (Ref. 205)
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Molecular Biology and Genetics

Molecular Biology

Statistics of barcoding coverage: Centrophorus harrissoni

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 0
Specimens with Barcodes: 29
Species With Barcodes: 1
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Conservation

Conservation Status

IUCN Red List Assessment


Red List Category
EN
Endangered

Red List Criteria
A2bd

Version
3.1

Year Assessed
2013

Assessor/s
Graham, K.

Reviewer/s
Simpfendorfer, C. & Kyne, P.M.

Contributor/s

Justification
The first Red List assessment (2003) for Harrisson’s Dogfish (Centrophorus harrissoni) (Critically Endangered) was based on the documented >99% decline of the species on upper continental slope grounds off central and southern New South Wales (NSW) and eastern Victoria, inferred from the results of fishery-independent trawl surveys. This part of its range is still continually fished and there is no evidence that the numbers of Harrisson’s Dogfish have recovered on these trawl grounds. Its relatively narrow continental slope habitat (275–1,050 m depth range), probable late age at maturity and very low fecundity (maximum of one or two pups every two years) make Harrisson’s Dogfish extremely vulnerable to rapid population depletion by commercial fishing (particularly trawling) and also prevents any quick recovery after such depletion.

However, since the first assessment, the species is now known to occupy a greater geographical range than previously thought and a number of conservation measures have been implemented. While records from the Kermadec and Norfolk Ridges are based on few specimens, there is reportedly little fishing effort in this peripheral part of its range. A recent longline survey and other observations confirmed the presence of significant numbers of Harrisson’s Dogfish along the southern Queensland and northern NSW upper continental slope, as well as on a series of offshore seamounts (Tasmantid Seamounts) off eastern Australia. Throughout this part of its range (~50%), there is only small-scale commercial fishing (drop-line and powered handline) which is thought to have minimal impact on Harrisson’s Dogfish numbers.

Several conservation measures have also been introduced specifically to protect and enhance Harrisson’s Dogfish numbers. Earlier restrictive catch limits (to prevent target fishing) have been replaced by a total ban on retaining any Harrisson’s Dogfish for sale. The Gulper Shark protection areas off Sydney and eastern Bass Strait have been increased in size and closed to all methods of fishing, and there is a ban on trawling below 700 m along the east coast south from Sydney (designed to protect all deepwater sharks). New management rules for the Tasmantid Seamounts, specifically designed to protect Harrisson’s Dogfish, have been introduced. The Derwent Hunter Seamount is now closed to all fishing while fishing on the Britannia and Queensland Seamounts is restricted to handlines with powered reels. The Barcoo and Taupo Seamounts remain closed to trawling but open to line fishing. However, all seamount fishing is subject to 100% monitoring, and there will also be a vessel interaction limit of three Gulper Sharks and if reached, the seamount will be closed to that boat for 12 months.

Recently calculated depletion estimates for Harrison's Dogfish off eastern Australia indicated a 79% reduction in virgin population. Considering this estimate, and the species' sporadic distribution on lightly or unfished ridges and seamounts in the Tasmin and adjacent seas, Harrisson’s Dogfish is now assessed as Endangered, with an overall population decline inferred to be about 70%.

History
  • 2003
    Critically Endangered
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Population

Population
Harrison's Dogfish was first recorded from FIS Endeavour survey catches during 1904-1914 (McCulloch 1915) but fishery impacts on the species' population did not begin until the 1970s when commercial trawling began on the NSW upper slope (Graham et al. 2001, Tilzey and Rowling 2001). Since then, gulper sharks, including Harrisson’s Dogfish, were commercially exploited off the east coast of Australia, but there has been no estimate of total population numbers.

In the northern half of its range off Australia’s east coast (southern Queensland to central New South Wales (NSW)), a small-scale line fishery targets teleosts along the upper slope and on offshore seamounts. A targeted Gulper Shark survey using auto-longlines on the upper slope between Brisbane and Tasmania in 2009 caught 105 Harrisson’s Dogfish off northern NSW with a mean catch rate of 3.3 dogfish per 1,000 hooks (Williams et al. 2012). On the same survey, 12 Harrisson’s Dogfish were caught at the Taupo Seamount (~200 nm off central NSW) at 4.0 dogfish per 1,000 hooks. In February 2011, auto-longlining over four days on the Britannia and Queensland Seamounts off southern Queensland caught 49 Harrisson’s Dogfish at 2.5 fish per 1,000 hooks (K. Graham pers. obs.). During 2011–12, the ‘Minor Line’ (handlines on mechanised reels) fishery that targets the teleost Hyperoglyphe antarctica on seamounts was scientifically monitored and 111 Harrisson’s Dogfish were recorded with an overall catch rate (across all seamounts) of 3.3 per 1,000 hooks; on Recorder and Britannia Seamounts, Harrisson’s Dogfish were targeted for tagging and catch rates as high as 40 per 1,000 hooks were achieved (K. Graham pers. obs.). The coastal drop-line fishery off northern NSW landed relatively small numbers of demersal sharks and the impact of this fishery on Harrisson’s Dogfish is considered low; in the seamount ‘Minor Line’ fishery, dogfishes are not retained and a high proportion of those captured are likely to survive if returned quickly to the sea.

In contrast, the relative abundance of the species in the southern half of its range between Newcastle (33°00’S) and Tasmania (44°00’S) has been severely impacted by commercial fishing. A fishery-independent trawl survey on the upper slope (200–650 m depth) off NSW between the Sydney area (33°30’S) and the Eden-Gabo Island area (38°20’S) in 1996–97 found a >99% decline in relative abundance of all Gulper Sharks (Centrophorus spp.) since the initial survey in 1976–77 (Andrew et al. 1997, Graham et al. 1997, 2001). Further south off eastern Bass Strait and Tasmania, trawling and targeted gillnet fishing in the 1980s and 1990s also severely depleted numbers (Daley et al. 2002). Although it is now illegal to retain Harrison's Dogfish for sale (AFMA 2012b), incidental fishing mortality by demersal trawlers and auto longliners targeting upper slope teleosts will continue to maintain pressure on the remnant population of Harrisson’s Dogfish off southeastern Australia.

The 2009 targeted longline survey for Gulper Sharks (see above) confirmed that numbers of Harrisson’s Dogfish remain low on regularly fished grounds between Sydney and Bass Strait (~0.4 dogfish per 1,000 hooks) and catches through this southern part of its range included no mature females. However, at three sites off Flinders Island that included areas closed to trawling (Daley et al. 2010), 85 Harrisson’s Dogfish were caught (6.3 dogfish per 1,000 hooks) suggesting that the protected areas were having a beneficial effect on population numbers.

In 2012, utilizing all available data, CSIRO (Commonwealth Scinetific and Industrial Organisation) scientists calculated depletion estimates and pre-fishery carrying capacity for Harrison's Dogfish in Australian waters (AFMA 2012a,b). The overall depletion estimate (proportion of the population remaining) was 21% (range 11-31%) with the estimate for the continental slope population 11% (4-20%) and seamount population 75% (50-100%).

With only two specimens known from New Zealand EEZ waters, and sporadic (nominal) records from the north Tasman and Coral Seas, there is no knowledge of the relative abundance of Harrisson’s Dogfish outside Australian waters. There is limited commercial fishing activity across these areas.

Assuming that the main population of Harrisson’s Dogfish is off eastern Australia (including adjacent seamounts and Lord Howe Island), it is likely that there is still some low-level fishing mortality, in both the lightly-fished northern part of its range and the severely depleted southern part of its range, possibly resulting in a continuing slow decrease in the total population.

Population Trend
Decreasing
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Threats

Major Threats
Commercial fishing activities constitute the main threat to Harrisson’s Dogfish because the core depth of the species (350–800 m) largely coincides with the most heavily fished depths by trawlers and longliners operating on the upper slope around southeastern Australia. In the period 1975–2000, the population south of Newcastle (central NSW) was severely impacted by trawling and targeted gillnetting and its relative abundance was reduced to <5% of historical levels (Graham et al. 2001, Daley et al. 2002, Wilson et al. 2009). Commercial fishing continues to impact on the remaining stock with up to five trawlers operating seasonally in the deepwater sector of the NSW Offshore Trawl Fishery between Newcastle (33°00’S) and Sydney (33°40’S) while south from Sydney about 30 trawlers and three auto longliners regularly operate in upper slope depths in the Commonwealth Trawl and Scalefish Hook Sectors of the Southern and Eastern Scalefish and Shark Fishery (SESSF). In 2010, The stock status for the three species of upper slope gulper sharks (Harrisson’s Dogfish, Endeavour Dogfish C. moluccensis and Southern Dogfish C. zeehaani) on southeastern Australian grounds was assessed as ‘overfished’ and ‘subject to overfishing’ (Stobutzki et al. 2011).

On the coast and adjacent seamounts off Queensland and northern NSW, small-scale line fishing (drop-line and minor-line) is believed to have minimal impact on Harrisson’s Dogfish. However, automatic longlining on seamounts in the Australian zone of the Coral and Tasman Seas (permissible under Australian Government permits) poses a greater potential threat to Harrisson’s Dogfish populations although the very steep terrain and high capture rates of (unwanted) spurdogs (Squalus spp.) make fishing by this method less likely at these locations (K. Graham pers. obs.).

North of New Zealand, a trawl fishery operates on the West Norfolk Ridge, and drop-lining for large teleosts occurs on the Three Kings Rise, West Norfolk Ridge and Wanganella Bank but, with only two records of Harrisson’s Dogfish from this region, it is unknown if these fishing activities have any impact on gulper shark populations, and there is no information on any gulper shark bycatch from any of these fishing activities (C. Duffy pers. comm. 2010). Because of its steep rocky topography, there is almost no trawling and very little longlining on the Kermadec Ridge.
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Endangered (EN) (A2bd)
  • IUCN 2006 2006 IUCN red list of threatened species. www.iucnredlist.org. Downloaded July 2006.
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Management

Conservation Actions

Conservation Actions
In 2002, the Australian Fishery Management Authority (AFMA) introduced trip limits for commercial vessels operating in the Southern and Eastern Scalefish and Shark Fishery (SESSF) of 150 kg (carcass weight) of gulper sharks including a maximum of 30 kg of Harrisson’s Dogfish. This was further reduced to a combined total of 15 kg per day (90 kg per trip for trips >6 days) for Harrisson’s Dogfish, Endeavour Dogfish, Southern Dogfish and Greeneye Spurdog (Squalus chloroculus) with a combined annual catch limited to 4.5 tonnes (AFMA 2010a). In NSW, similar complementary landing restrictions have also been legislated.

Spatial management measures designed to protect gulper sharks were introduced by AFMA in 2007 with the closure of small areas on the upper slope off Sydney (for Endeavour Dogfish) and eastern Bass Strait (for Harrisson’s Dogfish) to trawl and hook methods; two additional closures off eastern Bass Strait were implemented in December 2010 (AFMA 2010b). In addition, the closure of almost all ground deeper than 700 m south of Sydney (Orange Roughy Conservation Programme) also affords some protection to Harrisson’s Dogfish in the deeper part of its depth range (see Stobutzki et al. 2011). As part of AFMA’s upper-slope dogfish management strategy for the SESSF, all waters deeper than 183 m have been closed to shark-hook and gillnet methods, and the Barcoo and Taupo Seamounts have been closed to all fishing (AFMA 2010b).

In October 2012, a revised Upper-slope Dogfish Management Strategy was released by AFMA and included actions designed to rebuild the Harrisson’s Dogfish population (AFMA 2012b). The revised strategy ‘relies on a new network of spatial closures supplemented by a range of operational measures including regulated handling practices, 100% monitoring, move-on provisions and no retention of gulper sharks’. New provisions include increasing the areas of the Sydney and Eastern Bass Strait (Flinders Research Zone and Harrisson’s Dogfish Closure) closures, effective to all methods of fishing. Management of the Tasmantid Seamounts off NSW and Queensland have also been changed: the Derwent Hunter Seamount is now closed to all fishing while the Britannia and Queensland Seamounts are closed to demersal longlining with fishing restricted to handlines with powered reels. The Barcoo and Taupo Seamounts remain closed to trawling but open to line fishing. All seamount fishing is ‘subject to regulated handling practices and 100% monitoring’; there will also be a ‘vessel interaction limit of three gulper sharks and if reached the closure area will be closed to that boat for 12 months’. In addition, the taking of Harrison's Dogfish for sale is prohibited across the whole SESSF. Similarly, in February 2013, the NSW Government gazetted a regulation prohibiting the taking of Harrison's Dogfish in waters under its jurisdiction (NSWDPI 2013).

Harrisson’s Dogfish has also been nominated for listing as a threatened species under Australia’s Environment Protection and Biodiversity Conservation Act 1999, with a decision pending.

North of New Zealand where Harrisson’s Dogfish has been recorded, both the Kermadec and Colville Ridges are covered by large benthic protection areas (BPAs) (C. Duffy pers. comm. 2010).
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Relevance to Humans and Ecosystems

Benefits

Importance

fisheries: of no interest
  • Coppola, S.R., W. Fischer, L. Garibaldi, N. Scialabba and K.E. Carpenter 1994 SPECIESDAB: Global species database for fishery purposes. User's manual. FAO Computerized Information Series (Fisheries). No. 9. Rome, FAO. 103 p. (Ref. 171)
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Wikipedia

Dumb gulper shark

The dumb gulper shark, Centrophorus harrissoni, is a rare and endangered deepwater dogfish, known from only along the east coast of Australia and isolated spots north and west of New Zealand. It is also known as the dumb shark, Harrison's deep-sea dogfish, or Harrison's dogfish.[1]

Characteristics[edit]

The dumb gulper shark may grow to be 43 in (110 cm) long and has a long, robust head, a long, flattened snout, a large mouth, and large, green eyes, which help it see at 820 to 1260 ft (250 to 385 m) under water.[2][3] The body is slender and of moderate size, and is grey to greyish-brown in colour, with a paler underside. Of the two dorsal fins, the first is larger than the second, and each has a short spine, a white rear margin, and a dark blotch towards the front, which is more distinct in juveniles.[2] The large caudal fin is asymmetrical, with a longer upper than lower lobe.[3]

The broad teeth of this species differ between the upper and lower jaws, with the lower teeth being much larger. The teeth also differ between the male and female, with the male having much more erect, upright upper teeth, and upward-curving tips on the lowers.[2] The dumb gulper shark is very similar in appearance to the closely related little gulper shark.

Habitat[edit]

This shark is found off the east coast of Australia, New South Wales, Victoria, Queensland and Tasmania, and off New Zealand.[4][5] Its habitat is in the demersal zone on the upper to middle continental slope.

Behavior[edit]

These sharks eat mostly teleost fishes (particularly myctophids), cephalopods and crustaceans.[6] Females produce a maximum of one to two pups every one to two years. Evidence suggests that the left-side uterus is less functional than the right-side.[7] They can live up to 46 years on average.

Population[edit]

The population size is unknown, but numbers have decreased as much as 99% in some areas since the 1970s. This species is harvested, by demersal trawling or droplining, for meat and liver oil (squalene). Upper-slope dogfish species are more vulnerable to capture than midslope species, because they are targeted throughout their vertical distribution and most of their local geographic distribution.[8] The low reproductive rate, late age of maturity, and long lifespan typical of these sharks means they are likely unable to recover quickly after depletion.

Conservation[edit]

Action is being taken to preserve the dumb gulper, which includes being incorporated into the Environmental Protection and Biodiversity Conservation (EPBC) Act to create a plan to keep this species safe. In response to this species’ inherent low productivity and continuing reduced numbers, managers have introduced landing restrictions and area closures to enhance C. harrissoni stocks in southern Australian waters.[7]

References[edit]

  1. ^ a b Pogonoski, J. & Pollard, D. (2003). "Centrophorus harrissoni". IUCN Red List of Threatened Species. Version 2011.2. International Union for Conservation of Nature. Retrieved 5 April 2012. 
  2. ^ a b c White, W.T., Ebert, D.A. and Compagno, L.J.V. (2008) Description of two new species of gulper sharks, genusCentrophorus (Chondrichthyes: Squaliformes: Centrophoridae) from Australia. In: Last, P.R., White, W.T. and Pogonoski, J.J. (Eds.) Descriptions of New Australian Chondrichthyans. CSIRO Marine and Atmospheric Research Paper No. 022, CSIRO, Australia.
  3. ^ a b Compagno, L.J.V. (1984). "Sharks of the World. An Annotated and Illustrated Catalogue of Shark Species Known to Date, Vol. 4: Part 1: Hexanchiformes to Lamniformes". Rome: Food and Agriculture Organization of the United Nations. 
  4. ^ Scientists delighted to find rare shark off the east coast of Flinders Island, Tasmania
  5. ^ Duffy, Clintoni A. J. (1 June 2007). "First record of Centrophorus harrissoni from New Zealand, with observations on squamation in centrophoridae (squaliformes)". New Zealand Journal of Marine and Freshwater Research 41 (2): 163–173. doi:10.1080/00288330709509905. 
  6. ^ Daley, R., Stevens, J. and Graham, K. 2002. Catch analysis and productivity of the deepwater dogfish resource in southern Australia. Report by CSIRO Marine Research and NSW Fisheries to the Fisheries Research and Development Corporation. FRDC Project 1998/108.
  7. ^ a b Graham, K. J.; Daley, R. K. (1 January 2011). "Distribution, reproduction and population structure of three gulper sharks (Centrophorus, Centrophoridae) in south-east Australian waters". Marine and Freshwater Research 62 (6): 583. doi:10.1071/MF10158. 
  8. ^ Andrew, N.L., Graham, K.J., Hodgson, K.E. and Gordon, G.N.G. 1997. Changes after twenty years in relative abundance and size composition of commercial fishes caught during fishery independent surveys on SEF trawl grounds. NSW Fisheries Final Report Series No. 1 FRDC Project No. 96/139.
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