Dasyatis acutirostra

Taxonomy

Assessment Information

Geographic Range

Population

Habitat and Ecology

Threats

Conservation Actions

Bibliography

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Taxonomy [top]

Kingdom	Phylum	Class	Order	Family
ANIMALIA	CHORDATA	CHONDRICHTHYES	RAJIFORMES	DASYATIDAE

Scientific Name:

Dasyatis acutirostra

Species Authority:

Nishida & Nakaya, 1988

Common Name/s:

English

–

Sharpnose Stingray

Taxonomic Notes:

D. acutirostra was previously confused with D. zugei but is clearly distinguishable from larger eyeball diameter, dorsal tail fold absent or inconspicuous, larger pectoral and pelvic radials, more prespine separate centra and larger number of intestinal valve turns.

Potential synonym with Himantura microphthalma (Chen, 1948) where Chen might have overlooked ventral tail fold (H. Ishihara, pers. com.).

Assessment Information [top]

Red List Category & Criteria:	Near Threatened ver 3.1
Year Published:	2006
Assessor/s:	Huveneers, C.
Reviewer/s:	Fowler, S.L. & Kyne, P.M. (Shark Red List Authority)
Justification: Known from only a few specimens collected from the East China Sea and southern Japanese waters, the biology of Dasyatis acutirostra is virtually unknown. This species? range is heavily fished and it is likely taken as bycatch by the Japanese coastal bottom trawl fishery and, to a lesser extent, by set nets. Research is required to better define the species? distribution, biology and catch levels. This species is Near Threatened in recognition that any fishing impact is of concern because of its restricted geographical distribution, while increasing fishing pressure within its range would have dramatic effects on this regional endemic.

Geographic Range [top]

Range Description:	Limited known distribution in the East China Sea and southern Japanese waters (Nishida and Nakaya 1988).
Countries:	Native: China; Japan
FAO Marine Fishing Areas:	Native: Pacific – northwest
Range Map:	Click here to open the map viewer and explore range.

Population [top]

Population:	Unknown.
Population Trend:	Unknown

Habitat and Ecology [top]

Habitat and Ecology:	Known from only a few specimens collected from the East China Sea and southern Japanese waters. Holotype was caught by trawl net at a depth of 53 to 142 m. Biology is virtually unknown. However, one 72.5 cm DW male was found mature whilst a 35.4 cm DW male was still immature with soft and small claspers. Dasyatidae are mostly demersal in inshore waters, although several species range offshore and a few large species occur along the upper continental slopes as deep as 480 m. Several species are euryhaline while some others are confined to freshwater. All are aplacental viviparous. Litter varies between two to six young with gestation periods which may take as long as 12 months (Last and Compagno 1999). Life history parameters Age at maturity (years): Unknown. Size at maturity (disc width): Unknown (female); unknown, immature at 35.4 cm DW, mature at 72.5 cm DW (male). Longevity (years): Unknown. Maximum size (disc width): 72.5 cm DW. Size at birth (cm): Unknown. Average reproductive age (years): Unknown. Gestation time (months): Unknown. Reproductive periodicity: Unknown. Average annual fecundity or litter size: Unknown. Annual rate of population increase: Unknown. Natural mortality: Unknown.
Systems:	Marine

Habitat and Ecology:

Known from only a few specimens collected from the East China Sea and southern Japanese waters. Holotype was caught by trawl net at a depth of 53 to 142 m.

Biology is virtually unknown. However, one 72.5 cm DW male was found mature whilst a 35.4 cm DW male was still immature with soft and small claspers.

Dasyatidae are mostly demersal in inshore waters, although several species range offshore and a few large species occur along the upper continental slopes as deep as 480 m. Several species are euryhaline while some others are confined to freshwater. All are aplacental viviparous. Litter varies between two to six young with gestation periods which may take as long as 12 months (Last and Compagno 1999).

Life history parameters
Age at maturity (years): Unknown.
Size at maturity (disc width): Unknown (female); unknown, immature at 35.4 cm DW, mature at 72.5 cm DW (male).
Longevity (years): Unknown.
Maximum size (disc width): 72.5 cm DW.
Size at birth (cm): Unknown.
Average reproductive age (years): Unknown.
Gestation time (months): Unknown.
Reproductive periodicity: Unknown.
Average annual fecundity or litter size: Unknown.
Annual rate of population increase: Unknown.
Natural mortality: Unknown.

Systems:

Marine

Threats [top]

Major Threat(s):	Most likely taken as bycatch in the Japanese coastal bottom trawl fishery and to a lesser extent by set nets (H. Ishihara pers. com.). Care should be taken as any fishing impact on this species might have greater effects due to its narrow geographical distribution. An increase of fishing pressure in this location would have dramatic effects on this narrow ranging species. Stingrays are amongst the dominant ray components of landings in Indonesia, Thailand, Taiwan, Malaysia and elsewhere in Asia. However, the relative importance of species on a regional basis is poorly known and species-specific landing data are virtually non-existent.

Major Threat(s):

Most likely taken as bycatch in the Japanese coastal bottom trawl fishery and to a lesser extent by set nets (H. Ishihara pers. com.). Care should be taken as any fishing impact on this species might have greater effects due to its narrow geographical distribution. An increase of fishing pressure in this location would have dramatic effects on this narrow ranging species.

Stingrays are amongst the dominant ray components of landings in Indonesia, Thailand, Taiwan, Malaysia and elsewhere in Asia. However, the relative importance of species on a regional basis is poorly known and species-specific landing data are virtually non-existent.

Conservation Actions [top]

Conservation Actions:	Catch levels need to be documented and careful monitoring of fishing effort in the area of occurrence is needed to ensure that the current population is not detrimentally affected. Information on the species? biology is required to inform management decisions. Effective implementation of the Japanese National Plan of Action for the Conservation and Management of Sharks (under the FAO International Plan of Action: IPOA?Sharks) is required to facilitate the conservation and sustainable management of all chondrichthyan species in Japan.

Conservation Actions:

Catch levels need to be documented and careful monitoring of fishing effort in the area of occurrence is needed to ensure that the current population is not detrimentally affected. Information on the species? biology is required to inform management decisions.

Effective implementation of the Japanese National Plan of Action for the Conservation and Management of Sharks (under the FAO International Plan of Action: IPOA?Sharks) is required to facilitate the conservation and sustainable management of all chondrichthyan species in Japan.

Bibliography [top]

	IUCN. 2006. 2006 IUCN Red List of Threatened Species. www.iucnredlist.org. Downloaded on 04 May 2006. IUCN SSC Shark Specialist Group. Specialist Group website. Available at: http://www.iucnssg.org/. Last, P.R. and Compagno, L.J.V. 1999. Dasyatidae. In: K.E. Carpenter and V.H. Niem, V.H. (eds.) FAO species identification guide for fishery purposes. The living marine resources of the Western Central Pacific. Volume 3. Batoid fishes, chimaeras and bony fishes. Part 1 (Elopidae to Linophynidae). FAO, Rome, pp. 1479-1505. Nishida, K. and Nakaya, K. 1988. A new species of the genus Dasyatis (Elasmobranchii: Dasyatididae) from southern Japan and lectotype designation of D. zugei. Japanese Journal of Ichthyology 35(2):115?123. Nishida, K. and Nakaya, K. 1990. Taxonomy of the Genus Dasyatis (Elasmobranchii, Dasyatididae) from the North Pacific. In: H.L. Pratt, S.H. Gruber & T. Taniuchi (eds). Elasmobranchs as Living Resources: Advances in the Biology, Ecology, Systematics, and the Status of the Fisheries. NOAA Technical Report 90:327-345.

IUCN. 2006. 2006 IUCN Red List of Threatened Species. www.iucnredlist.org. Downloaded on 04 May 2006.

IUCN SSC Shark Specialist Group. Specialist Group website. Available at: http://www.iucnssg.org/.

Last, P.R. and Compagno, L.J.V. 1999. Dasyatidae. In: K.E. Carpenter and V.H. Niem, V.H. (eds.) FAO species identification guide for fishery purposes. The living marine resources of the Western Central Pacific. Volume 3. Batoid fishes, chimaeras and bony fishes. Part 1 (Elopidae to Linophynidae). FAO, Rome, pp. 1479-1505.

Nishida, K. and Nakaya, K. 1988. A new species of the genus Dasyatis (Elasmobranchii: Dasyatididae) from southern Japan and lectotype designation of D. zugei. Japanese Journal of Ichthyology 35(2):115?123.

Nishida, K. and Nakaya, K. 1990. Taxonomy of the Genus Dasyatis (Elasmobranchii, Dasyatididae) from the North Pacific. In: H.L. Pratt, S.H. Gruber & T. Taniuchi (eds). Elasmobranchs as Living Resources: Advances in the Biology, Ecology, Systematics, and the Status of the Fisheries. NOAA Technical Report 90:327-345.

Citation:	Huveneers, C. 2006. Dasyatis acutirostra. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. <www.iucnredlist.org>. Downloaded on 25 May 2012.
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