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Overview

Comprehensive Description

Biology

Found near shore on the continental shelf, more commonly on rocky and kelp-covered bottom (Ref. 43278, 11230). Feeds on crustaceans, mollusks (including top shells), small fishes and sea urchins. Oviparous (Ref. 43278, 50449). Grabs prey by protruding its jaw with considerable distance.
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Distribution

Range Description

Northwest Pacific: Japan, northern China, northeastern coast of Taiwan (Province of China), Korea, northern (Compagno 2001, D. Ebert pers. comm.).
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Western North Pacific.
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Northwest Pacific: off Japan, Korean Republic, northern China including Taiwan Island.
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Physical Description

Size

Maximum size: 1200 mm TL
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Max. size

120 cm TL (male/unsexed; (Ref. 247))
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Ecology

Habitat

A common, temperate-water bullhead shark of the western North Pacific continental shelf, occurring at moderate depths of 6 to 37 m, on or near the bottom. It prefers rocky areas (including reefs) and kelp-covered bottom.
  • 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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Habitat and Ecology

Habitat and Ecology
A common, temperate-water, benthic shark found on the continental shelf, at depths of 6?37 m (Compagno 2001, Smith 1942). Appears to prefer rocky areas. Including reefs, and kelp-covered substrates (Compagno 2001, Smith 1942). This species reaches a maximum size of 120 cm total length (TL), males mature at ~69 cm TL and size at birth is 18 cm TL (Compagno 2001). Females lay pairs of eggs among rocks or kelp at depths of 8?9 m, during 6?12 spawnings (from March to September) (Compagno 2001, Smith 1942). Preys on molluscs, small fishes and sea urchins (Compagno 2001, Smith 1942).

Systems
  • Marine
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Depth: 6 - 37m.
From 6 to 37 meters.

Habitat: demersal.
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Environment

demersal; marine; depth range 6 - 37 m (Ref. 247)
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Trophic Strategy

Found on the continental shelf, more commonly on rocky and kelp-covered bottom. Feeds on crustaceans, molluscs (including top shells), small fishes and sea urchins. Also in Ref. 9137.
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Life History and Behavior

Behavior

Diet

feeds on crustaceans, molluscs (including top shells [Trochidae; Gastropoda]), small fishes and sea urchins.
  • 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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Life Cycle

Oviparous. Eggs are laid in rocks or in kelp at depths of about 8 or 9 m and are present from March through September. Eggs are more abundant, however, in March and April. Eggs are hatched in about a year; size at hatching is about 18 cm. There may be a `nest' for several females laying eggs but this is not a true nest. A female lays two eggs at a time, for 6 to 12 spawnings.
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Conservation

Conservation Status

IUCN Red List Assessment


Red List Category
LC
Least Concern

Red List Criteria

Version
3.1

Year Assessed
2009

Assessor/s
Tanaka, S. & Nakaya, K.

Reviewer/s
Valenti, S.V. & Simpfendorfer, C. (Shark Red List Authority)

Contributor/s

Justification
A common, benthic shark with a relatively widespread distribution in the Northwest Pacific. Although probably of little interest to commercial fisheries, this species is caught as bycatch of gillnet and possibly other fisheries in its range. Habitat destruction and pollution are also threats to its inshore habitat. However, this species is common within its range, is probably relatively fecund (an oviparous species) and is assessed as Least Concern because there is no evidence to suggest that it has declined at the present time. Population trends and changes in habitat quality should be monitored throughout the species? range.
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Population

Population
Little is known about the population of this species, but it is very common in shallow waters of Japan (S. Tanaka pers. obs. 2007).

Population Trend
Stable
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Threats

Major Threats
This species is probably of little interest to fisheries, but is caught as bycatch by gillnet fisheries (Tanaka 2006) and possibly other fisheries in its range (Compagno 2001, S. Tanaka and K. Nakaya pers. obs. 2007). In northern Japan, and possibly elsewhere, its inshore habitat is threatened by marine pollution and coralline flats. Algae are declining in abundance, which will affect this species? prey items; Batillus, top shells sea urchins, and in turn may impact populations of H. japonicus (S. Tanaka pers. obs. 2007).

It is also a very popular aquarium species in Japan (S. Tanaka and K. Nakaya pers. obs. 2007).
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Least Concern (LC)
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Management

Conservation Actions

Conservation Actions
None in place. Population trends and changes in habitat quality should be monitored throughout the species? range. Research is also required on the species? biology.
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Relevance to Humans and Ecosystems

Benefits

Importance

fisheries: minor commercial; price category: unknown; price reliability:
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Wikipedia

Japanese bullhead shark

The Japanese bullhead shark (Heterodontus japonicus) is a species of bullhead shark, family Heterodontidae, found in the northwestern Pacific Ocean off the coasts of Japan, Korea, and China. This benthic shark occurs at depths of 6–37 m (20–121 ft) over rocky bottoms or kelp beds. Measuring up to 1.2 m (3.9 ft) long, it can be identified by its short, blunt head, two high dorsal fins with anterior spines, and pattern of irregularly shaped, vertical brown bands and stripes. The Japanese bullhead shark is a docile, slow-swimming species that feeds mainly on shelled invertebrates and small bony fishes. Reproduction is oviparous, with females laying spiral-flanged eggs in communal "nests". This species is of little interest to fisheries.

Taxonomy[edit]

The Japanese bullhead shark was originally described as Cestracion japonicus by ichthyologists Nicholas Miklouho-Maclay and William John Macleay, in an 1884 volume of Proceedings of the Linnean Society of New South Wales. The type specimen is a female caught off Tokyo, Japan. Other common names used for this species include bull head, cat shark, Japanese horn shark, Cestracion shark, and Port Jackson shark (which usually refers to Heterodontus portusjacksoni).[1][2]

Description[edit]

The color pattern of the Japanese bullhead shark distinguish it from similar species.

A modest-sized shark reaching a maximum known length of 1.2 m (3.9 ft), the Japanese bullhead shark has a cylindrical body with the short, wide head and blunt, pig-like snout typical of the bullhead sharks. The eyes lack a nictitating membrane and are followed by tiny spiracles. Shallow supraorbital ridges are present above the eyes, and the space between them is slightly concave. The nostrils are divided into incurrent and excurrent openings by long flaps of skin that reach the mouth; the incurrent opening is encircled by a groove while another groove runs from the excurrent opening to the mouth. The small mouth is positioned nearly at the tip of the snout; the front teeth are small with a sharp central cusp flanked by a pair of lateral cusplets, while the back teeth are broad and rounded. There are deep furrows at the corners of the mouth, extending onto both jaws.[1]

The first dorsal fin is very large and high, and is somewhat falcate (sickle-shaped); it originates over the bases of the pectoral fins. The second dorsal fin is much smaller but similar in shape, and originates over the rear tips of the pelvic fins. Both dorsal fins bear stout spines on their leading edges. The pectoral fins are large; the pelvic fins are much smaller than the first dorsal fin. The anal fin is placed well in front of the caudal fin, which is broad with a short lower lobe and a long upper lobe bearing a strong ventral notch near the tip. The dermal denticles are large and rough, particularly on the sides of the body. The coloration is light brown, with a series of diffuse-edged, darker wide bands interspersed with narrower stripes from snout to tail, numbering 11–14 in all. There is a faint lighter band on top of the head between the eyes, and a darker blotch beneath each eye.[1]

Distribution and habitat[edit]

The range of the Japanese bullhead shark extends from Japan to the Korean Peninsula, and southward along the coast of China to Taiwan. There is a single, apparently erroneous, record from off East Africa. This bottom-dwelling shark inhabits the continental shelf at a depth of 6–37 m (20–121 ft), preferring areas covered by rocks, rocky reefs, or kelp.[1]

Biology and ecology[edit]

A Japanese bullhead shark off Kawana, Japan.

The Japanese bullhead shark is a slow-moving predator that feeds on crustaceans, molluscs, small fishes, and sea urchins, often hunting for them while "walking" along the sea bottom with alternating motions of its pectoral and pelvic fins. When prey is found, it is seized with highly protrusible jaws and ground to pieces with the molar-like rear teeth.[1] Known parasites of this species include the copepod Dissonus pastinum,[3] and the haemogregarine protozoan Haemogregarina heterodontii.[4]

Like other members of its family, the Japanese bullhead shark is oviparous. Females produce large egg capsules bearing thin flanges spiraling three times around the outside and a pair of short tendrils at the tip. The eggs are deposited at a depth of 8–9 m (26–30 ft) within beds of rock or kelp.[1] Several females may spawn communally in a single "nest", which may contain up to 15 eggs total, though the females abandon the site afterward.[1][5] In Japanese waters, females lay pairs of eggs 6–12 times between March and September, with a peak in spawning activity in March and April. The eggs take about a year to hatch; the newborns measure 18 cm (7.1 in) long. Young sharks have proportionately higher dorsal fins and a similar but brighter color pattern than adults. Males attain sexual maturity at a length of 69 cm (27 in).[1]

Human interactions[edit]

Harmless to humans, the Japanese bullhead shark can be easily hand-caught by divers. It is of only minor fisheries interest as a source of food in Japan and likely elsewhere. It is also exhibited in Japanese public aquariums.[1] The conservation status of this species has not been evaluated by the International Union for Conservation of Nature (IUCN).[2] It has apparently disappeared from offshore waters in the Bohai Sea, possibly as a consequence of climate change.[6]

References[edit]

  1. ^ a b c d e f g h i 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. 39–40. ISBN 92-5-104543-7. 
  2. ^ a b Froese, Rainer and Pauly, Daniel, eds. (2009). "Heterodontus japonicus" in FishBase. October 2009 version.
  3. ^ Deets, G.B. and M. Dojiri (1990). "Dissonus pastinum n. sp. (Siphonostomatoida: Dissonidae), a copepod parasitic on a horn shark from Japan". Beaufortia 41 (8): 49–54. 
  4. ^ Baker, J.R., R. Muller and D. Rollinson, ed. (1995). Advances in Parasitology, Volume 36. Academic Press. p. 186. ISBN 0-12-031736-2. 
  5. ^ Martin, R.A. Heterodontiformes: Bullhead Sharks. ReefQuest Centre for Shark Research. Retrieved on October 28, 2009.
  6. ^ Yang, J., L. Li and S. Xia (1995). "Influence of Climate Change on Living Resources in the Offshore Waters of China". In Beamish, R.J. Climate Change and Northern Fish Populations. NRC Research Press. pp. 531–535. ISBN 0-660-15780-2. 
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