Hemigaleus microstoma

Taxonomy

Assessment Information

Geographic Range

Population

Habitat and Ecology

Threats

Conservation Actions

Taxonomy [top]

Kingdom	Phylum	Class	Order	Family
ANIMALIA	CHORDATA	CHONDRICHTHYES	CARCHARHINIFORMES	HEMIGALEIDAE

Scientific Name:

Hemigaleus microstoma

Species Authority:

Bleeker, 1852

Infra-specific Taxa Assessed:

See Hemigaleus microstoma (Southeast Asia subpopulation)

Common Name/s:

English

–

Sickelfin Weasel Shark, Weasel Shark

Synonym/s:

Hemigaleus machlani

Negogaleus brachugnathus

Negogaleus microstoma

Assessment Information [top]

Red List Category & Criteria:	Least Concern ver 3.1
Year Assessed:	2003
Assessor/s	Simpfendorfer, C.A. (SSG Australia & Oceania Regional Workshop, March 2003)
Evaluator/s:	Fowler, S. & Cavanagh, R.D. (Shark Red List Authority)
Justification: This species occurs on continental shelves out to 170 m throughout its disjunct range in the Indo-West Pacific. In northern Australia it is commonly taken in trawl fisheries, including those for prawns and fish and also taken in gillnet and longline fisheries, but not in large numbers. In other countries data is lacking, but it appears not to be abundant. This small species has relatively high productivity - it produces large litters (up to 19 pups) after a six-month gestation period, probably grows fast, and matures at an early age. These life history parameters are likely to enable it to sustain reasonable levels of fishing pressure and it is assessed as Least Concern globally. However, it is fished in high numbers in South East Asia, and despite its relatively high productivity, there is enough concern to warrant a Near Threatened assessment in this region (where it may meet the criterion Vulnerable A2d).

Geographic Range [top]

Range Description:	This species has an apparently disjunct distribution in the tropical Indo-West Pacific, with populations in southern India and Sri Lanka; Gulf of Thailand, Malaysia and Singapore; Java; southern china and Taiwan; Philippines; and northern Australia. Compagno (1984) reports that it is not extremely abundant throughout its range.
Countries:	Native: Australia (New South Wales); China; Indonesia; Malaysia; Papua New Guinea; Philippines; Singapore; Sri Lanka; Thailand
FAO Marine Fishing Areas:	Native: Indian Ocean – eastern; Pacific – northwest; Pacific – southwest; Pacific – western central

Population [top]

Population:	There are no population estimates for any of the populations.
Population Trend:	Unknown

Habitat and Ecology [top]

Habitat and Ecology:	Biological data is only available from Australian waters. The diet of Hemigaleus microstoma is composed almost exclusively of cephalopods (especially octopus). It is viviparous, producing litters of 1 to 19 individuals after a six month gestations period. The young are born at around 30 cm, males mature at 60 cm, female mature at 65 cm, and they reach a maximum size of 110 cm. There are no age and growth data, but they are assumed to be relatively fast growing and early maturing. This life history is relatively productive for an elasmobranch and should enable it to withstand a reasonable level of fishing pressure. They utilize continental shelf waters down to 170 m, but little is known of their habitat use. With a diet composed mostly of octopus they may spend a considerable amount of time around reef and weedy areas frequented by these prey.
Systems:	Marine

Habitat and Ecology:

Biological data is only available from Australian waters. The diet of Hemigaleus microstoma is composed almost exclusively of cephalopods (especially octopus). It is viviparous, producing litters of 1 to 19 individuals after a six month gestations period. The young are born at around 30 cm, males mature at 60 cm, female mature at 65 cm, and they reach a maximum size of 110 cm. There are no age and growth data, but they are assumed to be relatively fast growing and early maturing. This life history is relatively productive for an elasmobranch and should enable it to withstand a reasonable level of fishing pressure.

They utilize continental shelf waters down to 170 m, but little is known of their habitat use. With a diet composed mostly of octopus they may spend a considerable amount of time around reef and weedy areas frequented by these prey.

Systems:

Marine

Threats [top]

Major Threat(s):	This species is caught in trawl fisheries throughout its range. In northern Australia it is commonly taken in trawl fisheries, including those for prawns (including the Shark Bay, Exmouth Gulf, Gulf of Carpentaria and Queensland east coast fisheries) and fish (including the Pilbara trawl fishery) (Last and Stevens 1994, Simpfendorfer et al. 1999). In northern Australia it is also taken in gillnet and longline fisheries, but not in big numbers. In other countries data is lacking, however, it is caught in high numbers in areas of South East Asia (e.g., Indonesia) and more information is needed on its status and threats throughout this region.

Major Threat(s):

This species is caught in trawl fisheries throughout its range. In northern Australia it is commonly taken in trawl fisheries, including those for prawns (including the Shark Bay, Exmouth Gulf, Gulf of Carpentaria and Queensland east coast fisheries) and fish (including the Pilbara trawl fishery) (Last and Stevens 1994, Simpfendorfer et al. 1999). In northern Australia it is also taken in gillnet and longline fisheries, but not in big numbers. In other countries data is lacking, however, it is caught in high numbers in areas of South East Asia (e.g., Indonesia) and more information is needed on its status and threats throughout this region.

Conservation Actions [top]

Conservation Actions:	No conservation measures are in place for this species.

Conservation Actions:

No conservation measures are in place for this species.

Citation:	Simpfendorfer, C.A. 2003. Hemigaleus microstoma. In: IUCN 2008. 2008 IUCN Red List of Threatened Species. <www.iucnredlist.org>. Downloaded on 03 December 2008.
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