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Lifespan, longevity, and ageing

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Maximum longevity: 12 years (wild)
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Diagnostic Description

provided by FAO species catalogs
fieldmarks: Dorsal fins with spines, anal fin present, supraorbital ridges greatly enlarged, colour pattern of dark broad bands on head, back and tail. Supraorbital ridges very high, more prominent than in any other Heterodontus, abruptly truncated posteriorly; interorbital space deeply concave, depth between ridges about equal to eye length. Anterior holding teeth with a cusp and a pair of cusplets in adults, posterior molariform teeth strongly carinate and not greatly expanded and rounded. Pre-first dorsal-fin length 22 to 28%, and anal-caudal space 5 to 8%, of total length. Lateral trunk denticles fairly large and rough. Propterygium separate, not fused to mesopterygium. First dorsal-fin spine directed obliquely posterodorsally in adults; first dorsal-fin origin anterior to pectoral-fin insertions, slightly behind pectoral-fin midbases and well posterior to fifth gill openings; first dorsal-fin insertion well anterior to pelvic-fin origins and well behind pectoral-fin insertions; first dorsal-fin free rear tip about opposite to or slightly behind pelvic-fin origins; first dorsal fin moderately high and semifalcate or angular in adults, height 10.8 to 15.2% of total length, slightly larger than pelvic fins. Second dorsal-fin origin well in front of pelvic-fin rear tips, second dorsal fin somewhat falcate or angular and nearly as large as first dorsal fin. Anal fin subangular or rounded to weakly falcate, apex reaching lower caudal-fin origin when laid back; anal-caudal space between 1 and 2 times anal-fin base. Total vertebral count 106 to 108, precaudal count 71 or 72, monospondylous precaudal count 34 or 35, diplospondylous precaudal count 36 to 38, pre-first dorsal-fin spine count 16 to 18, and count from diplospondylous transition to second dorsal-fin spine 8 to 11. Egg cases with flat thin spiral flanges that are diagonal to case axis and a pair of long, slender tendrils on case apex, flanges with 6 or 7 turns. A large species, mature between 60 and 152 cm. Background colour of dorsal surface light brown or yellowish brown with five broad diffuse-edged brown or blackish saddles, but without light or dark spots; saddles not arranged in a harness pattern; head with a dark bar on interorbital surface and a single broad dark blotch under eye; fins without abrupt dark tips and white dorsal-fin apices; hatchlings without whorls on fins and body, colour pattern as in adults.

References

  • Compagno , 1984
  • Compagno & Niem, 1998
  • Fowler, 1941
  • Last & Stevens, 1994
  • McLaughlin & O'Gower, 1971
  • Michael, 1993
  • Whitley, 1940

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bibliographic citation
Sharks of the world An annotated and illustrated catalogue of shark species known to date. Volume 2 Bullhead, mackerel and carpet sharks (Heterodontiformes, Lamniformes and Orectolobiformes). Leonard J.V. Compagno 2001.  FAO Species Catalogue for Fishery Purposes. No. 1, Vol. 2. Rome, FAO. 2001. p.269.
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Distribution

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Western South Pacific: East coast of Australia, from southern Queensland and New South Wales, with a doubtful record from Tasmania, and a possible record from the top of the Cape York Peninsula.
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Sharks of the world An annotated and illustrated catalogue of shark species known to date. Volume 2 Bullhead, mackerel and carpet sharks (Heterodontiformes, Lamniformes and Orectolobiformes). Leonard J.V. Compagno 2001.  FAO Species Catalogue for Fishery Purposes. No. 1, Vol. 2. Rome, FAO. 2001. p.269.
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Size

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Maximum said to be 152 cm long and attaining at least 130 cm, but most individuals are below 122 cm. Young hatch at about 17 cm. Males mature at about 60 cm and females at about 70 cm.
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Sharks of the world An annotated and illustrated catalogue of shark species known to date. Volume 2 Bullhead, mackerel and carpet sharks (Heterodontiformes, Lamniformes and Orectolobiformes). Leonard J.V. Compagno 2001.  FAO Species Catalogue for Fishery Purposes. No. 1, Vol. 2. Rome, FAO. 2001. p.269.
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Brief Summary

provided by FAO species catalogs
A moderately common benthic and epibenthic shark of the southern Australian continental shelf at moderate depths,ranging from close inshore in the intertidal zone to 93 m. Found on reefs, in kelp and in beds of seagrass. This shark often wedges its way between rocks in search of prey. The egg cases are dropped by females in seaweeds or sponges from 20 to 30 m depth on the bottom, during July and August, and hatch after about eight months. Eggs are commonest on the bottom in August and September but are found throughout the year. In captivity a newly hatched female matured and began to lay eggs at an age of 11.8 years and a length of about 70 cm. The crested bullhead shark feeds primarily on sea urchins (echinoids), but also crustaceans, molluscs and small fishes.
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Sharks of the world An annotated and illustrated catalogue of shark species known to date. Volume 2 Bullhead, mackerel and carpet sharks (Heterodontiformes, Lamniformes and Orectolobiformes). Leonard J.V. Compagno 2001.  FAO Species Catalogue for Fishery Purposes. No. 1, Vol. 2. Rome, FAO. 2001. p.269.
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Benefits

provided by FAO species catalogs
Interest to fisheries minimal, taken by bottom trawlers but not utilized commercially. Utilization by aquarium trade uncertain, but an obvious candidate because of its unusual appearance and striking colour pattern. Observed and photographed by divers, but not a special focus of ecotourism.
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Sharks of the world An annotated and illustrated catalogue of shark species known to date. Volume 2 Bullhead, mackerel and carpet sharks (Heterodontiformes, Lamniformes and Orectolobiformes). Leonard J.V. Compagno 2001.  FAO Species Catalogue for Fishery Purposes. No. 1, Vol. 2. Rome, FAO. 2001. p.269.
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Diagnostic Description

provided by Fishbase
Body with broad blackish bands or saddle markings (Ref. 9838).
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Recorder
Cristina V. Garilao
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Life Cycle

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Oviparous, paired eggs are laid. Embryos feed solely on yolk (Ref. 50449). Distinct pairing with embrace (Ref. 205).
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Morphology

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Dorsal spines (total): 2; Dorsal soft rays (total): 0; Analspines: 0; Analsoft rays: 0
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Trophic Strategy

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A moderately common benthic and epibenthic shark found on the continental shelf . Occurs from close inshore to about 93 m depth. Feeds primarily on sea urchins, but also on crustaceans, mollusks, and small fishes.
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Biology

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A moderately common benthic and epibenthic shark found on the continental shelf (Ref. 247, 43278). Occurs from close inshore to about 93 m depth (Ref. 247, 43278). Feeds primarily on sea urchins, but also on crustaceans, mollusks, and small fishes (Ref. 31369). Oviparous, egg cases spirally flanged and with long tendrils (Ref. 6871). Hatches at about 22 cm (Ref. 6871).
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Importance

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fisheries: minor commercial; price category: unknown; price reliability:
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Crested bullhead shark

provided by wikipedia EN

The crested bullhead shark (Heterodontus galeatus) is an uncommon species of bullhead shark, in the family Heterodontidae. It lives off the coast of eastern Australia from the coast to a depth of 93 m (305 ft). This shark can be distinguished from other members of its family by the large size of the ridges above its eyes and by its color pattern of large dark blotches. It typically attains a length of 1.2 m (3.9 ft).

Nocturnal and bottom-dwelling, the crested bullhead shark favors rocky reefs and vegetated areas, where it hunts for sea urchins and other small organisms. It is oviparous, with females producing spiral-shaped egg capsules that are secured to seaweed or sponges with long tendrils. Sexual maturation is slow, with one female in captivity not laying eggs until almost 12 years of age. The International Union for Conservation of Nature has assessed this harmless shark as of Least Concern; it is of no economic interest and suffers minimal mortality from bycatch, recreational fishing, and shark nets.

Taxonomy

British zoologist Albert Günther originally described the crested bullhead shark as Cestracion galeatus in the 1870 eighth volume of Catalogue of the Fishes in the British Museum. He chose the specific epithet galeatus from the Latin for "helmeted", referring to the prominent ridges above the shark's eyes that also give it its common name.[2][3]

Subsequent authors moved this species to the genera Gyropleurodus and Molochophrys before placing it in Heterodontus. The type specimen is a 68-cm-long female caught off Australia.[2] This shark may also be referred to as crested shark, crested bull shark, crested horn shark, and crested Port Jackson shark.[4]

Description

The high ridges above the eyes of the crested bullhead shark are its most distinctive feature.

The head of the crested bullhead shark is short and wide, with a blunt, pig-like snout. The eyes are placed high on the head and lack nictitating membranes. The supraorbital ridges above the eyes of this species are larger than any other member of its family. The nostrils are separated into incurrent and excurrent openings by a long flap of skin that reaches the mouth. A furrow encircles the incurrent opening and another furrow runs from the excurrent opening to the mouth, which is located nearly at the tip of the snout. The teeth at the front of the jaws are small and pointed with a central cusp and two lateral cusplets, while those at the back of the jaws are wide and molar-like. The deep furrows at the corners of the mouth extend onto both jaws.[2]

The pectoral fins are large and rounded, while the pelvic and anal fins are smaller and more angular. The first dorsal fin is moderately tall with a rounded to angular apex and a stout spine on the leading margin, originating behind the pectoral fins. The second dorsal fin resembles the first and is almost as large, and is located between the pelvic and anal fins. The caudal fin is broad, with a strong ventral notch near the tip of the upper lobe. The dermal denticles are large and rough, especially on the flanks. The coloration consists of five brown to black, diffusely edged saddles on a light tan background. There are dark marks on top of the head between the crests and below each eye. Most crested bullhead sharks measure no more than 1.2 m (4 ft) long, but a few may reach 1.5 m (5 ft).[2]

Distribution and habitat

The crested bullhead shark is found on or near the bottom.

The range of the crested bullhead shark is restricted to the warm temperate waters along the eastern coast of Australia, from Cape Moreton, Queensland, to Batemans Bay, New South Wales. Also dubious records exist of this species from off Cape York Peninsula in the north and Tasmania in the south. This species co-occurs with the related Port Jackson shark (H. portusjacksoni) across much of its range, but is generally much rarer except off southern Queensland and northern New South Wales, where it tends to replace the other species.[1]

Bottom-dwelling in nature, the crested bullhead shark is found over the continental shelf from the intertidal zone to a depth of 93 m (305 ft), being more common in deeper waters. It prefers rocky reefs, mats of seaweed, and seagrass beds.[1]

Biology and ecology

A crested bullhead shark feeding on an egg of the Port Jackson shark.

The crested bullhead shark is a slow-moving, nocturnal species often seen wedging its head between rocks in search of food. It feeds primarily on the sea urchins Centrostephanus rodgersii and Heliocidaris erythrogramma, but has also been known to take a variety of other invertebrates and small fishes.[1] A steady diet of sea urchins may stain the teeth of this shark pinkish purple.[5] The crested bullhead shark is also a major predator of the eggs of the Port Jackson shark, which are seasonally available and rich in nutrients. Individual sharks have been observed taking the egg capsules in their mouths and chewing on the tough casing, rupturing it and allowing the contents to be sucked out; egg capsules may also be swallowed whole.[6] Unlike the Port Jackson shark, the crested bullhead shark is not known to form large aggregations.[1]

The egg case of the crested bullhead shark has distinctive, long tendrils at one end.

Crested bullhead sharks are oviparous with a possibly annual reproductive cycle. Females produce 10–16 eggs per year during late winter in July and August, though Michael (1993) noted that egg-laying may continue year-round.[1] The egg cases measure around 11 cm (4.3 in) in length, with a pair of thin flanges spiraling 6–7 times around the outside and two slender tendrils up to 2 m (6.6 ft) long at one end, used to attach the capsule to seaweed or sponges.[1][2] The capsules are usually deposited at a depth of 20–30 m (66–98 ft), much deeper than the Port Jackson shark, though there is a single record of an egg being found only 8.6 m (28 ft) down. The time to hatching has been variously reported as 5 and 8–9 months; the newly emerged young measure 17–22 cm (6.7–8.7 in) long and resemble the adults. Last and Stevens (1994) gave the lengths at maturity for males and females at 60 cm (24 in) and 70 cm (28 in), respectively, though mature males as small as 53.5 cm (21.1 in) long were later found off Queensland. Growth and aging has been documented for one captive female at the Taronga Park Aquarium, which grew an average of 5 cm (2.0 in) per year and did not lay eggs until she was almost 12 years old.[1]

Human interactions

Inoffensive towards humans, the crested bullhead shark is of little interest to recreational or commercial fisheries. It is seldom caught on hook-and-line. Commercial bottom trawl prawn fisheries operating off Queensland and New South Wales take this species as bycatch; the impact of these activities on the population is uncertain as this species is not recorded separately from the Port Jackson shark. However, most bullhead sharks caught in these fisheries survive to be released alive. Crested bullhead sharks are likely also caught in mesh shark nets used to protect beaches; again, most are able to survive the experience.

Because of the limited mortality suffered by this species from various human activities, the International Union for Conservation of Nature has assessed this species as of Least Concern, albeit also recommending that it be carefully monitored given its restricted distribution and overall uncommonness. The range of the crested bullhead shark overlaps with several marine protected areas; additionally, it was listed as a declared animal in Schedule 3 of the 1997 Queensland Marine Parks (Moreton Bay) Zoning Plan, which regulates its collection in Moreton Bay Marine Park.[1]

References

  1. ^ a b c d e f g h i Kyne, P.M.; Bennett, M.B. (2016). "Heterodontus galeatus". IUCN Red List of Threatened Species. 2016: e.T41824A68625634. doi:10.2305/IUCN.UK.2016-1.RLTS.T41824A68625634.en. Retrieved 13 November 2021.
  2. ^ a b c d e Compagno, L.J.V. (2002). Sharks of the World: An Annotated and Illustrated Catalogue of Shark Species Known to Date (Volume 2). Rome: Food and Agriculture Organization. pp. 38–39. ISBN 92-5-104543-7.
  3. ^ Günther, A.C.L.G. (1870). Catalogue of the Fishes in the British Museum, Volume 8. The Trustees. p. 416.
  4. ^ Froese, Rainer; Pauly, Daniel (eds.) (2009). "Heterodontus galeatus" in FishBase. October 2009 version.
  5. ^ Huxley, T.H. (1883). Fish Diseases. W. Clowes and Sons. p. 15.
  6. ^ Powter, D.W. & W. Gladstone (2008). "Embryonic mortality and predation on egg capsules of the Port Jackson shark Heterodontus portusjacksoni (Meyer)". Journal of Fish Biology. 72 (3): 573–584. doi:10.1111/j.1095-8649.2007.01721.x.
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Crested bullhead shark: Brief Summary

provided by wikipedia EN

The crested bullhead shark (Heterodontus galeatus) is an uncommon species of bullhead shark, in the family Heterodontidae. It lives off the coast of eastern Australia from the coast to a depth of 93 m (305 ft). This shark can be distinguished from other members of its family by the large size of the ridges above its eyes and by its color pattern of large dark blotches. It typically attains a length of 1.2 m (3.9 ft).

Nocturnal and bottom-dwelling, the crested bullhead shark favors rocky reefs and vegetated areas, where it hunts for sea urchins and other small organisms. It is oviparous, with females producing spiral-shaped egg capsules that are secured to seaweed or sponges with long tendrils. Sexual maturation is slow, with one female in captivity not laying eggs until almost 12 years of age. The International Union for Conservation of Nature has assessed this harmless shark as of Least Concern; it is of no economic interest and suffers minimal mortality from bycatch, recreational fishing, and shark nets.

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Habitat

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A moderately common benthic and epibenthic shark of the southern Australian continental shelf at moderate depths, ranging from close inshore in the intertidal zone to 93 m. Found on reefs, in kelp and in beds of seagrass.

Reference

Compagno, L.J.V. (2001). Sharks of the world. An annotated and illustrated catalogue of shark species known to date. Volume 2. Bullhead, mackerel and carpet sharks (Heterodontiformes, Lamniformes and Orectolobiformes). FAO Species Catalogue for Fishery Purposes. No. 1, Vol. 2. Rome, FAO. 269p.

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