Dumb gulper shark

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Dumb gulper shark
Centrophorus harrissoni.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Order: Squaliformes
Family: Centrophoridae
Genus: Centrophorus
Species:
C. harrissoni
Binomial name
Centrophorus harrissoni
McCulloch, 1915
Centrophorus harrissoni distmap.png
Range of dumb gulper shark (in blue)

The dumb gulper shark (Centrophorus harrissoni) is a rare and endangered deepwater dogfish, found along the east coast of Australia and in 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]

Contents

Characteristics

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 y 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 lobe compared to the lower lobe. [3]

The broad teeth of this species differs 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 lower teeth. [2] The dumb gulper shark is very similar in appearance to the closely related little gulper shark.

Habitat

This shark is found off the coasts of eastern Australia and New Zealand. [4] [5] Its habitat is in the demersal zone on the upper to middle continental slope.

Behaviour

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. Newborn pups range in size from 35 cm to 40 cm. 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

The population size is unknown, but numbers have decreased as much as 99% in some areas since the 1970s. This species is harvested, by trawling or drop lining, for meat and liver oil (squalene). Upper-slope dogfish species are more vulnerable to capture than mid-slope 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

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]

The New Zealand Department of Conservation has classified the dumb gulper shark as "Data Deficient" with the qualifier "Threatened Overseas" under the New Zealand Threat Classification System. [9]

Related Research Articles

<span class="mw-page-title-main">Squaliformes</span> Order of fishes

The Squaliformes are an order of sharks that includes about 126 species in seven families.

The Centrophoridae are a family of squaliform sharks. The family contains just two genera and about 15 species. They are sometimes called gulper sharks, but this is also the name of a specific species in the family, Centrophorus granulosus. These are generally deepwater fish. While some, such as the gulper shark C. granulosus, are found worldwide and fished commercially, others are uncommon and little-known. Their usual prey is other fish; some are known to feed on squid, octopus, and shrimp. Some species live on the bottom (benthic), while others are pelagic. They are ovoviviparous, with the female retaining the egg-cases in her body until they hatch.

<span class="mw-page-title-main">Bramble shark</span> Species of shark

The bramble shark is one of the two species of sharks in the family Echinorhinidae. Aside from the eastern Pacific Ocean, it is found in tropical and temperate waters worldwide. This rarely encountered shark swims close to the bottom of the seafloor, typically at depths of 400–900 m (1,300–3,000 ft), though it may enter much shallower water. The bramble shark has a stout body with two small dorsal fins positioned far back and no anal fin. It can be readily identified by the large, thorn-like dermal denticles scattered over its body, some of which may be fused together. It is purplish brown or black in color and grows up to 3.1 m (10 ft) long.

Centrophorus is a genus of squaliform sharks. These deep-water sharks, found in temperate and tropical oceans throughout the world, are characterized by grey or brown bodies, large green eyes, and spines on both dorsal fins. These spines give them their name, from Greek κεντρον, kentron meaning "thorn" and φέρειν, pherein meaning "to bear".

<span class="mw-page-title-main">Lowfin gulper shark</span> Species of shark

The lowfin gulper shark is a large deepwater dogfish in the family Centrophoridae.

<span class="mw-page-title-main">Smallfin gulper shark</span> Species of shark

The smallfin gulper shark or endeavour dogfish, is a medium-sized deepwater dogfish in the family Centrophoridae.

<span class="mw-page-title-main">Leafscale gulper shark</span> Species of shark

The leafscale gulper shark is a dogfish of the family Centrophoridae. C. squamosus is reported to have a lifespan of approximately 70 years, based on otolith ring counts. It was the first described species in the genus Centrophorus, which now contains 13 species.

<span class="mw-page-title-main">Mosaic gulper shark</span> Species of shark

The mosaic gulper shark is a small rare deepwater dogfish, found in the Pacific Ocean around Honshū, Japan and the Hawaiian Islands at depths between 260 and 728 m. It is one of 13 described species in the genus Centrophorus.

<span class="mw-page-title-main">Little gulper shark</span> Species of shark

The little gulper shark is a small, deepwater dogfish of the family Centrophoridae.

<span class="mw-page-title-main">Gulper shark</span> Species of shark

The gulper shark is a long and slender dogfish usually about three feet in length generally found in deep, murky waters all around the world. It is a light grayish brown, paler ventrally, with a long snout and large greenish eyes. This deep water shark has two dorsal fins with long, grooved spines and the second dorsal fin smaller than the first. Its upper teeth are blade-like and lower have finely serrated edges. This tertiary consumer feeds on mainly fish such as bony fish, but also cephalopods such as squid and other invertebrates like crustaceans. The gulper shark is currently an endangered species mainly because of exploitation by humans and their abnormally long gestation period and low fecundity, preventing their population from recovering. Because of the depth of their habitat, they are considered little to no threat to humans.

<span class="mw-page-title-main">Kitefin shark</span> Species of shark

The kitefin shark or seal shark is a species of squaliform shark in the family Dalatiidae, and the type species in its genus. It is found sporadically around the world, usually close to the sea floor at depths of 200–600 m (660–1,970 ft). With a sizable oil-filled liver to maintain neutral buoyancy, this shark is able to cruise slowly through the water while expending little energy. The kitefin shark, the largest luminous vertebrate on record, has a slender body with a very short, blunt snout, large eyes, and thick lips. Its teeth are highly differentiated between the upper and lower jaws, with the upper teeth small and narrow and the lower teeth large, triangular, and serrated. Its typical length is 1.0–1.4 m (3.3–4.6 ft), though examples as long as 5.9 ft (180 cm) have been encountered.

<span class="mw-page-title-main">Prickly dogfish</span> Species of fish

The prickly dogfish is a poorly known species of dogfish shark in the family Oxynotidae, inhabiting temperate Australian and New Zealand waters. Reaching a length of 75 cm (30 in), this brown to gray shark has a very thick body with a prominent "humpback" and extremely rough skin. It is further characterized by two enormous, sail-like dorsal fins placed relatively close together. Both dorsal fins have a spine embedded mostly within the fleshy leading portion of the fin; the first dorsal spine is tilted forward.

<span class="mw-page-title-main">Draughtsboard shark</span> Species of shark

The draughtsboard shark is a species of catshark, and part of the family Scyliorhinidae, so named for its "checkerboard" colour pattern of dark blotches. It is endemic to New Zealand, where it is also known as the carpet shark. This shark typically reaches 1 m (3.3 ft) in length and has a thick body with a broad, flattened head and a capacious mouth. Its two dorsal fins are placed far back on the body, with the first much larger than the second.

<span class="mw-page-title-main">Blackfin gulper shark</span> Species of shark

The blackfin gulper shark is a dogfish of the family Centrophoridae in the Northwest Pacific.

<span class="mw-page-title-main">Portuguese dogfish</span> Species of shark

The Portuguese dogfish or Portuguese shark, is a species of sleeper shark of the family Somniosidae. This globally distributed species has been reported down to a depth of 3,675 m (12,057 ft), making it the deepest-living shark known. It inhabits lower continental slopes and abyssal plains, usually staying near the bottom. Stocky and dark brown in color, the Portuguese dogfish can be distinguished from similar-looking species by the small spines in front of its dorsal fins. Its dermal denticles are also unusual, resembling the scales of a bony fish. This species typically reaches 0.9–1 m (3.0–3.3 ft) in length; sharks in the Mediterranean Sea are much smaller and have distinct depth and food preferences.

<span class="mw-page-title-main">Smooth lanternshark</span> Species of shark

The smooth lanternshark or slender lanternshark is a species of dogfish shark in the family Etmopteridae, found widely in the Atlantic and Pacific Oceans. It inhabits benthic environments at a depth of 274–1,000 m (899–3,281 ft), and pelagic environments at a depth of 0–708 m (0–2,323 ft). The smooth lanternshark forms a species group with the larger blurred lanternshark, both of which are distinguished from other members of their family by small, irregularly arranged dermal denticles with a truncated shape. This species has a slender, dark brown body with an indistinct black band on the sides over the pelvic fins, and reaches 50 cm (20 in) in length. This slow-growing, ovoviviparous shark feeds on smaller squid, fishes, and fish eggs. Smooth lanternsharks are often caught as bycatch in eastern Atlantic and Japanese commercial fisheries. The International Union for Conservation of Nature (IUCN) has evaluated this species as of Least Concern because of its wide distribution and limited threats.

<span class="mw-page-title-main">Southern sleeper shark</span> Species of shark

The southern sleeper shark, or Whitley's sleeper shark, is a deepwater benthopelagic sleeper shark of the family Somniosidae found in the southern and subantarctic extremes of the Atlantic, Indian and Pacific Oceans, and some northern reaches of the Antarctic oceans. It has been recorded near the southernmost areas of South America, near South Africa, southern Australia, Tasmania and New Zealand, as well as more remote locations in the south-central Indian Ocean.

The frog shark is a very rare species of squaliform shark mainly found in deep water in the Pacific Ocean. It is in the sleeper shark family Somniosidae with the Greenland shark.

<span class="mw-page-title-main">Western gulper shark</span> Species of fish

The western gulper shark is a species of squaliform shark discovered in 2008. The species had previously been identified as a variant of the dumb gulper shark, however was differentiated based on morphology. The western gulper is known from the waters of Western Australia, as well as Indonesia, East Timor, and islands in the Southern Indian Ocean. This shark is classified as "least concern" by the IUCN.

<span class="mw-page-title-main">Southern dogfish</span> Species of shark

The southern dogfish is a species of shark in the family Centrophoridae. It was described in 2008 along with the western gulper shark, and belongs to genus Centrophorus. It is mainly found in the Indian and Pacific ocean, but they are distributed in other oceans as well. As a result, it is one of the more recent and elusive types of shark to date.

References

  1. 1 2 Finucci, B.; Cheok, J.; Cotton, C.F.; Kulka, D.W.; Neat, F.C.; Rigby, C.L.; Tanaka, S.; Walker, T.I. (2020). "Centrophorus harrissoni". IUCN Red List of Threatened Species . 2020: e.T41740A68614118. doi: 10.2305/IUCN.UK.2020-3.RLTS.T41740A68614118.en . Retrieved 12 November 2021.
  2. 1 2 3 White, W.T., Ebert, D.A. & Compagno, L.J.V. (2008). Description of two new species of gulper sharks, genus Centrophorus (Chondrichthyes: Squaliformes: Centrophoridae) from Australia (PDF), pp. 1–21. In: P.R. Last, W.T. White & J.J. Pogonoski (eds). Descriptions of New Australian Chondrichthyans. CSIRO Marine & Atmospheric Research Paper 022, 358 pp.
  3. 1 2 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" (PDF). Rome: Food and Agriculture Organization of the United Nations.[ permanent dead link ]
  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. Bibcode:2007NZJMF..41..163D. 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. 1 2 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.
  9. Duffy, Clinton A. J.; Francis, Malcolm; Dunn, M. R.; Finucci, Brit; Ford, Richard; Hitchmough, Rod; Rolfe, Jeremy (2018). Conservation status of New Zealand chondrichthyans (chimaeras, sharks and rays), 2016 (PDF). Wellington, New Zealand: Department of Conservation. p. 9. ISBN   9781988514628. OCLC   1042901090.