|Scientific Name:||Dasyatis acutirostra|
|Species Authority:||Nishida & Nakaya, 1988|
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.).
|Red List Category & Criteria:||Near Threatened ver 3.1|
|Reviewer(s):||Fowler, S.L. & Kyne, P.M. (Shark Red List Authority)|
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.
|Range Description:||Limited known distribution in the East China Sea and southern Japanese waters (Nishida and Nakaya 1988).|
|FAO Marine Fishing Areas:||
Pacific – northwest
|Range Map:||Click here to open the map viewer and explore range.|
|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.
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.
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.
|Citation:||Huveneers, C. 2006. Dasyatis acutirostra. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 31 July 2014.|
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