|Scientific Name:||Himantura hortlei|
|Species Authority:||Last, Manjaji-Matsumoto & Kailola, 2006|
|Red List Category & Criteria:||Vulnerable A4cd ver 3.1|
|Assessor(s):||White, W., Manjaji, M. & Fahmi|
|Reviewer(s):||Valenti, S.V. & Notarbartolo di Sciara, G. (Shark Red List Authority)|
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.
|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.
|FAO Marine Fishing Areas:||
Pacific – western central
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||Common within its restricted range (W. White pers. obs.).|
|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).|
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:||None in place.|
Food and Agriculture Organization of the United Nations. 2007. The world's mangroves 1980-2005. FAO Forestry Paper 153. Rome, Italy.
IUCN. 2009. IUCN Red List of Threatened Species (ver. 2009.2). Available at: www.iucnredlist.org. (Accessed: 3 November 2009).
Last, P.R., Manjaji-Matsumoto, M. and Kailola, P.J. 2006. Himantura hortlei n. sp., a new species of whipray (Myliobatiformes: Dasyatidae) from Irian Jaya, Indonesia. Zootaxa 1239: 19-34.
White, W.T., Last, P.R., Stevens, J.D., Yearsley, G.K., Fahmi and Dharmadi. 2006. Economically Important Sharks and Rays of Indonesia. Australian Centre for International Agricultural Research, Canberra, Australia.
|Citation:||White, W., Manjaji, M. & Fahmi 2009. Himantura hortlei. The IUCN Red List of Threatened Species. Version 2014.3. <www.iucnredlist.org>. Downloaded on 27 May 2015.|
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