Himantura hortlei

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	RAJIFORMES	DASYATIDAE

Scientific Name:

Himantura hortlei

Species Authority:

Last, Manjaji-Matsumoto & Kailola, 2006

Common Name/s:

English

–

Hortle's Whipray

Assessment Information [top]

Red List Category & Criteria:	Vulnerable A4cd ver 3.1
Year Published:	2009
Assessor/s:	White, W., Manjaji, M. & Fahmi
Reviewer/s:	Valenti, S.V. & Notarbartolo di Sciara, G. (Shark Red List Authority)
Contributor/s:
Justification: Hortle's Whipray (Himantura hortlei) is a moderately large stingray that is possibly endemic New Guinea. It occurs in shallow waters (to 10 m depth) in estuaries and over intertidal mud flats. It is threatened by habitat destruction and intense fishing pressure throughout its known range. Although beach seine fisheries operating in its intertidal waters try to avoid it, it is still regularly caught as bycatch. This species? shallow water habitat is also heavily impacted by mangrove removal and mining practices, which are intense in the region. Mangrove area in Papua New Guinea has reduced by >30% since 1980. Hortle's Whipray is assessed as Vulnerable on the basis of suspected declines as a result of continuing high levels of exploitation and declines in extent and quality of its habitat.

Geographic Range [top]

Range Description:	Western Central Pacific: known only from Papua (Irian Jaya) (Last et al. 2006). Possibly southern Papua New Guinea (Last et al. 2006). FAO Area: 71.
Countries:	Native: Indonesia (Irian Jaya)
FAO Marine Fishing Areas:	Native: Pacific – western central
Range Map:	Click here to open the map viewer and explore range.

Population [top]

Population:	Common within its restricted range (W. White pers. obs.).
Population Trend:	Decreasing

Habitat and Ecology [top]

Habitat and Ecology:	Found in coastal marine habitats, over shallow intertidal mud flats, and in estuaries (White et al. 2006). Depth range is probably from the shore to 10 m depth (W. White pers. obs, Last et al. 2006). Viviparous, with histotrophy. Little else is known of the biology. This is a moderately large stingray, reaching 70.7 cm disc width (DW) (Last et al. 2006). Size at birth is <20 cm DW (Last et al. 2006).
Systems:	Marine

Habitat and Ecology:

Found in coastal marine habitats, over shallow intertidal mud flats, and in estuaries (White et al. 2006). Depth range is probably from the shore to 10 m depth (W. White pers. obs, Last et al. 2006). Viviparous, with histotrophy. Little else is known of the biology. This is a moderately large stingray, reaching 70.7 cm disc width (DW) (Last et al. 2006). Size at birth is <20 cm DW (Last et al. 2006).

Systems:

Marine

Threats [top]

Major Threat(s):	Seine net fishermen targeting prawns are the main fishing threat to this species. Fishers try to avoid catching it, but it is still a regular incidental catch. Habitat destruction is a major threat to this species. The removal of large areas of mangrove forest and mining practices (which are intense in this area) are most likely heavily impacting this species? shallow water habitat. Estimated mangrove area in Papua New Guinea fell from 545,000 hectares in 1980 to 380,000 hectares in 2005 (a reduction of >30%) (FAO 2007). This was caused primarily by human pressures for rural livelihoods, commercial activities and overexploitation of mangrove forest for timber for housing and carvings (FAO 2007). Pollution from the rivers also poses a significant threat.

Major Threat(s):

Seine net fishermen targeting prawns are the main fishing threat to this species. Fishers try to avoid catching it, but it is still a regular incidental catch.

Habitat destruction is a major threat to this species. The removal of large areas of mangrove forest and mining practices (which are intense in this area) are most likely heavily impacting this species? shallow water habitat. Estimated mangrove area in Papua New Guinea fell from 545,000 hectares in 1980 to 380,000 hectares in 2005 (a reduction of >30%) (FAO 2007). This was caused primarily by human pressures for rural livelihoods, commercial activities and overexploitation of mangrove forest for timber for housing and carvings (FAO 2007). Pollution from the rivers also poses a significant threat.

Conservation Actions [top]

Conservation Actions:	None in place.

Conservation Actions:

None in place.

Citation:	White, W., Manjaji, M. & Fahmi 2009. Himantura hortlei. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 19 May 2013.
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