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Hypogaleus hyugaensis

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA CHONDRICHTHYES CARCHARHINIFORMES TRIAKIDAE

Scientific Name: Hypogaleus hyugaensis
Species Authority: (Miyosi, 1939)
Common Name(s):
English Blacktip Topeshark, Blacktip Topeshark, Pencil Shark
Synonym(s):
Eugaleus hyugaensis Miyosi, 1939

Assessment Information [top]

Red List Category & Criteria: Near Threatened ver 3.1
Year Published: 2005
Date Assessed: 2005-10-01
Assessor(s): Simpfendorfer, C. & Compagno, L.J.V.
Reviewer(s): Musick, J.A. & Fowler, S.L. (Shark Red List Authority)
Justification:
This assessment is based on the information published in the 2005 shark status survey (Fowler et al. 2005).

The Blacktip Topeshark (Hypogaleus hyugaensis) is a small triakid shark with a patchy distribution in the Indo-West Pacific. It is of minor importance in fisheries and is unlikely to face any immediate threat of extinction. However, its patchy distribution and relatively low abundance throughout its range increase the potential for future fishing pressure to cause problems.

Geographic Range [top]

Range Description: Recorded in the western Pacific from Japan (Miyosi 1939), Taiwan (Province of China) (Chen 1963) and Australia (Western Australia, South Australia, Victoria, New South Wales, southern Queensland (Heald 1987, Last and Stevens 1994); in the Western Indian Ocean from South Africa (KwaZulu-Natal), Tanzania (Zanzibar) and Kenya (Smith 1957, Bass et al. 1975b). Compagno (1988) dismissed the reported occurrence of this species from the Arabian Gulf as a case of a mis-identified species of Paragaleus randalli. Generally believed to have an Indo-West Pacific distribution (Compagno 1984b, Last and Stevens 1994) although this may be discontinuous and the species is apparently rare or uncommon except off southern Australia. The occurrence of this species in the deeper waters of the continental shelf (40-230m), however, may make recording its precise distribution more difficult (Compagno 1988). It has only been reported in Australian waters in recent years, and the distribution map of Compagno (1984b) failed to recognise its occurrence there. Last and Stevens (1994) gave the distribution in Australian waters as south of 20°S. However, it is observed to occur only very infrequently in the shark fishery in south-eastern Australia (T. Walker pers. Comm.), suggesting that it rarely occurs in this part of its range. It is unknown whether there are discrete subpopulations in the Western Indian Ocean, off Australia and in the Northwest Pacific off Japan and Taiwan (POC).
Countries:
Native:
Australia (New South Wales, Queensland, South Australia, Victoria, Western Australia); Japan; Kenya; South Africa; Taiwan, Province of China; Tanzania, United Republic of
FAO Marine Fishing Areas:
Native:
Indian Ocean – western; Pacific – northwest
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population Trend: Unknown

Habitat and Ecology [top]

Habitat and Ecology: There are few details of the biology of Blacktip Topeshark available in the literature. To supplement this published information, unpublished data from a biological monitoring project in the Western Australian shark fishery is also included below. Bass et al. (1975b) reported specimens up to 127 cm total length (TL) from the east African coast. Reports of this species from Asia are all for specimens less than 90 cm. Last and Stevens (1994) reported a maximum length of 130 cm. The maximum size of this species recorded from extensive catch sampling in the Western Australia shark fishery is 117 cm (Simpfendorfer pers. Data). Bass et al. (1975b) reported stomach contents from two specimens from Africa, both of which contained teleosts. Stevens (1990) reported that of nine specimens caught in southern Western Australia six contained teleosts and four cephalopods. Blacktip Topeshark is placentally viviparous and has been reported to have a seasonal reproductive cycle by Bass et al. (1975b) and Stevens (1990). Recent results from the biological monitoring of the catch of the Western Australia commercial shark fishery have provided a clearer picture of the reproductive biology of Blacktip Topeshark (Simpfendorfer unpublished data). Males mature at approximately 98 cm and females at approximately 102 cm. Ovulation occurs in March and April, while the largest embryos are observed from December to February. Last and Stevens (1994) suggest that the gestation period was greater that 12 months, with parturition around February. The gestation period is probably around 10-11 months. Litter sizes range from 3-15, with a mean of 10. On the basis of full term embryos the size at birth is approximately 30 cm, a value similar to that of 33-35 cm suggested by Bass et al. (1975b) from full term embryos observed in southern Africa. Pregnant females do not produce yolky ova, suggesting that breeding occurs every second year.
Systems: Marine

Threats [top]

Major Threat(s): There are no targeted fisheries for Blacktip Topeshark, but it is caught as bycatch in a number of fisheries throughout its range, including Australia, South Africa and Japan. It is taken in demersal gillnets set by commercial shark fishers in western Australia (Simpfendorfer and Donohue 1998). Catch and effort data are available in this fishery from 1989-1990 and show that although catches have decreased from 12t to 6t over this period the catch rates have remained stable, suggesting there has been little impact on the stocks (Simpfendorfer unpubl.). The species is also caught in trawl fisheries off the east coast of southern and east Africa, including the shrimp trawl fishery off KwaZulu-Natal. Little data are available for this fishery, but intensive fishing may have caused some decline in the stocks. There are currently no data available on the occurrence of this species in other commercial fisheries. However, it is probable that it is caught in bottom fisheries (e.g., trawl, gillnet and longline) on the outer continental shelf where it occurs. It is unlikely to be caught regularly in artisanal fisheries because of its restriction to deeper parts of the shelf.

Conservation Actions [top]

Conservation Actions: There are currently no specific management or conservation measures in place for this species. However, the directed shark fishery in Western Australia that catches this species is a limited entry fishery with effort controls and gear restrictions (Simpfendorfer and Donohue 1998).

Citation: Simpfendorfer, C. & Compagno, L.J.V. 2005. Hypogaleus hyugaensis. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 23 September 2014.
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