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Overview

Comprehensive Description

Biology

Lives on continental shelves and upper slopes on or near the bottom. Also found in coastal waters on sand or mud bottoms. Feeds on small bottom organisms using its barbels to poke the bottom with its snout. Ovoviviparous, with 12 young in a litter.
  • 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

Northwest Pacific: this species is distributed throughout Japan (Southern Hokkido to Ryukido Island), off northern China (and also Taiwan, Province of China) from the East China Sea, the Yellow Sea, Bohai Sea, and southwest of Korea (Yamada et al. 2007).
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Northwest Pacific: Japan, Korea, northern China. Does not occur in the Western Central Pacific (Ref. 31368).
  • 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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Western North Pacific.
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Physical Description

Size

Max. size

136 cm TL (female)
  • 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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Diagnostic Description

Pristiophorus japonicus has a long, narrow, and narrowly tapering rostrum (rostrum length is 26-29% of TL), distance from rostral tip to barbels about equal or slightly greater than distance from barbels to mouth (1:1.1-1.2); distance from rostral barbels to nostrils about equal to distance from nostrils to 1st gill slits. About 15-26 large rostral teeth on each side of the rostrum in front of the barbels, 9-17+ behind them; distance from mouth to nostrils 1.1-1.2 times internarial space. Tooth rows 34-58 in upper jaw. Dorsal and pectoral fins covered with denticles in large specimens. Lateral trunk denticles largely unicuspidate. First dorsal fin origin behind free rear tips of pectorals by eye length or more (Ref. 247).Caudal fin almost straight, with slender upper and lower lobes; pectoral well developed but are not ray-like (Ref. 6871).
  • 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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Ecology

Habitat

Habitat and Ecology

Habitat and Ecology
A sawshark of temperate waters over continental shelves and upper slopes on or near sand or mud bottom (Compagno in prep). Found at depths of 50-800 m (Yano 2000).

Usually produces 12 pups per litter (Compagno in prep.). It grows to a maximum total length of 136-153 cm, with males maturing at 80-100 cm and females maturing at approximately 100 cm (Compagno in prep.). Size at birth is approximately 30 cm TL (Yamada et al. 2007). Feeds on small bottom dwelling organisms (Compagno in prep).

The species may make vertical migrations, according to water temperature, from shallow coastal waters to the upper continental slope (S. Tanaka pers. obs. 2007). The species can only be collected in coastal waters of the Izu Peninsula, Shizuoka, in early spring when water temperature is at its lowest (S. Tanaka pers. obs. 2007).

Systems
  • Marine
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Environment

demersal; marine; depth range 0 - 500 m (Ref. 54710)
  • FAO-FIGIS 2005 A world overview of species of interest to fisheries. Chapter: Pristiophorus japonicus. Retrieved on 21 June 2005, from www.fao.org/figis/servlet/species?fid=14565. 2p. FIGIS Species Fact Sheets. Species Identification and Data Programme-SIDP, FAO-FIGIS (Ref. 54710)
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Trophic Strategy

Lives on continental shelves and upper slopes on or near the bottom. Also found in coastal waters on sand or mud bottoms (Ref 247). Also in Ref. 9137. Feeds on small bottom organisms using its barbels to poke the bottom with its snout (Ref 247). A carnivor (Ref. 9137).
  • 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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Life History and Behavior

Life Cycle

Ovoviviparous, embryos feed solely on yolk (Ref. 50449).
  • 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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Conservation

Conservation Status

IUCN Red List Assessment


Red List Category
DD
Data Deficient

Red List Criteria

Version
3.1

Year Assessed
2009

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

Reviewer/s
Valenti, S.V., Fowler, S.L. & IUCN SSG Asia Northwest Pacific Red List Workshop participants (Shark Red List Authority)

Contributor/s

Justification
The Japanese Sawshark (Pristiophorus japonicus) is uncommon through its range and lives in the benthic zone in sandy, muddy bottoms. There is little information available on the population size. This species is a utilized bycatch of gillnets, bottom longline and trawl fisheries, and is particularly susceptible to capture in gillnets due to the thorns on its snout. The species is rarely captured, but no information is available to determine whether it is naturally rare or may have already been depleted. Very little information is available on this species and it is not possible to assess it beyond Data Deficient at present, but mortality in fisheries and population trends should be investigated as a priority.
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Population

Population
This species is apparently uncommon throughout its range (Yamada et al. 2007). No other information is available.

Population Trend
Unknown
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Threats

Major Threats
Probably of limited importance to fisheries, though in Japan its meat is considered of high quality and used for human consumption (Compagno in prep).

This species is captured as a utilised bycatch of gill nets, trawl nets and bottom longline fisheries. This is not a commercial species, but it is particularly susceptible to capture in gillnets because of the thorns on the snout (Yamada et al. 2007). This species is captured as bycatch in gillnet fisheries targeting spiny lobster set in less than 20 m depth. Although the fishery operates from September-April, the species only occurs as bycatch during March-April. It is thought that the species moves into deeper waters throughout the rest of the year. It is captured occasionally at depth of 200-400 m by trawl net fisheries in the East China Sea (Yamada et al. 2007). It is also an uncommon catch of trawl net fisheries operating in Suruga Bay, Japan (S. Tanaka pers. obs. 2007).
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Data deficient (DD)
  • IUCN 2006 2006 IUCN red list of threatened species. www.iucnredlist.org. Downloaded July 2006.
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Management

Conservation Actions

Conservation Actions
There are no specific conservation measures in place for this species.

According to the Law of Fisheries of China, bottom trawling is banned within certain areas of Chinese waters (Y. Wang pers. comm. 2007). Bottom trawling is restricted in certain zones and at different times in shallow water (Y. Wang pers. comm. 2007). Individual Provinces must apply national regulation within China. They also apply their own regulations on the basis of national regulations (Y. Wang pers. comm. 2007).
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Relevance to Humans and Ecosystems

Benefits

Importance

fisheries: commercial
  • 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

Japanese sawshark

The Japanese sawshark (Pristiophorus japonicus) is a species of sawshark in the family Pristiophoridae. This shark has a long, narrow rostrum. Its first dorsal fin originates behind the tips of the pectoral fins, and its caudal fin is angled almost straight in line with the body. The Japanese sawshark reaches an maximum length of up to 1.36 m (4 ft 6 in).

Range and Habitat[edit]

Found in the northwest Pacific Ocean around Japan, Korea, and northern China between latitudes 48°N and 22°N. It is found over the sandy or muddy bottoms of the continental shelf at depths of 50 to 800 m (160 to 2,620 ft). This species may vertically migrate in the water column because of changes in temperature.

Behavior[edit]

The Japanese sawshark has a varied diet of small benthic organisms. Like seemingly all sawsharks, this species is ovoviviparous. After an unknown gestation period, the female shark gives live birth to around 12 pups. These pups average around 30 cm (12 in) long. At sexual maturity the male is 80 to 100 cm (31 to 39 in) long, and the female is around 100 cm (39 in) long.

Conservation[edit]

With little information on population size or frequency of bycatch, the Japanese sawshark is listed by the IUCN Red List as being Data Deficient. It is not clear if this shark's apparent rarity is because of natural reasons, or because the population has already been depleted. Due to its benthic lifestyle, and because the range of this shark is heavily fished, it is safe to assume that the Japanese sawshark is at considerable risk of being caught as bycatch in bottom trawling and gillnet operations. Because of its habitat and behavior, this shark poses no threat to humans.

References[edit]

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