Hemigaleus microstoma

Taxonomy

Assessment Information

Geographic Range

Population

Habitat and Ecology

Threats

Conservation Actions

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Taxonomy [top]

Kingdom	Phylum	Class	Order	Family
ANIMALIA	CHORDATA	CHONDRICHTHYES	CARCHARHINIFORMES	HEMIGALEIDAE

Scientific Name:

Hemigaleus microstoma

Species Authority:

Bleeker, 1852

Common Name/s:

English

–

Sickelfin Weasel Shark, Sickle Fin Weasel Shark, Weasel Shark

Synonym/s:

Hemigaleus machlani Herre, 1929

Negogaleus brachugnathus Chu, 1960

Negogaleus microstoma Whitley, 1940

Taxonomic Notes:

Previously considered to occur in Australian waters, but the Australian individuals were recently described as a new species, Hemigaleus australiensis (White et al. 2005). Specimens from the Red Sea need to be critically examined.

Assessment Information [top]

Red List Category & Criteria:

Vulnerable A2d+3d+4d ver 3.1

Year Published:

2009

Assessor/s:

White, W.T.

Reviewer/s:

Simpfendorfer, C.A., Stevens, J.D. & Valenti, S.V. (Shark Red List Authority)

Contributor/s:

Justification:
The Sickle Fin Weasel Shark (Hemigaleus microstoma) is taken in a variety of inshore fisheries throughout its range. It appears to be a naturally uncommon species, thus the heavy fishing pressure through its range is of great concern. This species is not as productive as the closely related Australian Weasel Shark (Hemigaleus australiensis), i.e., with an average of 4?8 pups per year per female (based on two pregnancies per year) and thus less likely to be able to withstand fishing pressure. It is thus assessed as Vulnerable based on suspected declines as a result of the high level of exploitation throughout its range, which is likely to increase in the future and will have a great impact on a naturally uncommon species such as this.

History:

2003	–	Least Concern (IUCN 2003)
2003	–	Least Concern

Geographic Range [top]

Range Description:	Indian Ocean, northwest and western central Pacific: India, Sri Lanka, Myanmar, Thailand, Malaysia, Indonesia, Philippines, China, Taiwan and possibly the Red Sea.
Countries:	Native: China; India; Indonesia; Malaysia; Myanmar; Philippines; Sri Lanka; Taiwan, Province of China; Thailand
FAO Marine Fishing Areas:	Native: Indian Ocean – western; Pacific – northwest; Pacific – western central
Range Map:	Click here to open the map viewer and explore range.

Population [top]

Population:	Not particularly common throughout its range. Appears to be naturally not abundant as with many other hemigaleids.
Population Trend:	Decreasing

Habitat and Ecology [top]

Habitat and Ecology:	Hemigaleus microstoma is known from the insular and continental shelves, in shallow waters to depths of at least 170 m (White et al. 2006). Attains 114 cm TL. Males reach maturity at about 75 cm TL and females from 75?78 cm TL (White et al. 2007). Young are born at about 47 cm TL (White et al. 2007). Litter size is 2?4 (mean 3.3) with possibly two pregnancies per year thus a gestation of less than six months (White et al. 2007). A specialist feeder which feeds almost exclusively on cephalopods.
Systems:	Marine

Habitat and Ecology:

Hemigaleus microstoma is known from the insular and continental shelves, in shallow waters to depths of at least 170 m (White et al. 2006). Attains 114 cm TL. Males reach maturity at about 75 cm TL and females from 75?78 cm TL (White et al. 2007). Young are born at about 47 cm TL (White et al. 2007). Litter size is 2?4 (mean 3.3) with possibly two pregnancies per year thus a gestation of less than six months (White et al. 2007). A specialist feeder which feeds almost exclusively on cephalopods.

Systems:

Marine

Threats [top]

Major Threat(s):	Known to be caught in inshore and offshore artisanal fisheries throughout its range and retained. Caught in drifting and bottom gillnets and on longlines. Meat is utilized for human consumption and offal is processed into fishmeal (Compagno in prep). Fins are utilized but of lower value due to their small size (White et al. 2006).

Major Threat(s):

Known to be caught in inshore and offshore artisanal fisheries throughout its range and retained. Caught in drifting and bottom gillnets and on longlines. Meat is utilized for human consumption and offal is processed into fishmeal (Compagno in prep). Fins are utilized but of lower value due to their small size (White et al. 2006).

Conservation Actions [top]

Conservation Actions:	None in place.

Conservation Actions:

None in place.

Citation:	White, W.T. 2009. Hemigaleus microstoma. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 25 May 2013.
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