Narke japonica

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	NARKIDAE

Scientific Name:	Narke japonica
Species Authority:	(Temminck & Schlegel, 1850)
Synonym/s:	Torpedo japonica Temminck & Schlegel, 1850

Assessment Information [top]

Red List Category & Criteria:	Vulnerable A2d+3d+4d ver 3.1
Year Published:	2009
Assessor/s:	Carvalho, M.R. de & McCord, M.E.
Reviewer/s:	Fowler, S.L., Valenti, S.V. & IUCN SSG Asia Northwest Pacific Red List Workshop participants (Shark Red List Authority)
Contributor/s:
Justification: Narke japonica is a small inshore and offshore electric ray found off Japan, Korea, China, and Taiwan, Province of China. Heavy fishing pressure, particularly shrimp trawling in which this species is thought to be taken as bycatch in exists throughout the majority of its range. It is believed that post- discard survivorship is very low in electric rays. Although little specific information is available on this species’ population status, given its apparently restricted range in an area where historic and current fishing pressure is known to be intensive, it is likely that population numbers have been significantly reduced. Serious declines have been documented in populations of similar species, where they are heavily fished. This species is assessed as Vulnerable, on the basis of suspected declines as a result of continuing high levels of exploitation. Further study on this species’ life history and catch levels is required.

Geographic Range [top]

Range Description:	Northwest Pacific: occurs from off Japan, Korea, China, Taiwan Province of China, and the South China Sea near Hong Kong (Compagno and Last 1999).
Countries:	Native: China; Japan; Korea, Democratic People's Republic of; Korea, Republic of; Taiwan, Province of China
FAO Marine Fishing Areas:	Native: Pacific – northwest
Range Map:	Click here to open the map viewer and explore range.

Population [top]

Population:	Population size is unknown.
Population Trend:	Unknown

Habitat and Ecology [top]

Habitat and Ecology:	A little-known but locally common inshore and offshore sleeper ray in temperate to subtropical waters (Compagno and Last 1999). Reaches a maximum total length (TL) of at least 37 cm (Compagno and Last 1999). Males mature between 23–37 cm TL and females at ~35 cm TL (Compagno and Last 1999). Little else is known of its biology.
Systems:	Marine

Threats [top]

Major Threat(s):	Taken as bycatch in both inshore and offshore trawl fisheries throughout its distribution where both historical and current fishing pressure is high. Batoids are heavily exploited in the Andaman Sea, where intensive trawl fisheries operate on the western coast of Thailand (Simpfendorfer et al. 2005). Probably not all bycatch of this species is landed, but survival of discards will presumably be very poor. Electric ray species appear to be generally less common now than previously off Thailand (C. Vidthyanon pers. obs. 2007). Despite species-specific data on catches and population trends generally lacking for most electric rays, significant declines have been documented where data are available for species that have been heavily fished (e.g., Narcine bancroftii). The electric ray, N. bancroftii, occurs in the western Atlantic, matures at a very early age (two years) and is relatively fecund (up to 20 pups per litter). Despite this, Shepherd and Myers (2005) documented declines in N. bancroftii, to 2% (95% confidence intervals 0.5–5%) of its baseline abundance in 1972 in the Northern Gulf of Mexico, most probably caused by intense shrimp trawling. Similar declines were also documented in Narcine bancroftii in US trawl surveys and diver surveys off Florida (Carvalho et al. 2007).

Major Threat(s):

Taken as bycatch in both inshore and offshore trawl fisheries throughout its distribution where both historical and current fishing pressure is high. Batoids are heavily exploited in the Andaman Sea, where intensive trawl fisheries operate on the western coast of Thailand (Simpfendorfer et al. 2005). Probably not all bycatch of this species is landed, but survival of discards will presumably be very poor. Electric ray species appear to be generally less common now than previously off Thailand (C. Vidthyanon pers. obs. 2007).

Despite species-specific data on catches and population trends generally lacking for most electric rays, significant declines have been documented where data are available for species that have been heavily fished (e.g., Narcine bancroftii). The electric ray, N. bancroftii, occurs in the western Atlantic, matures at a very early age (two years) and is relatively fecund (up to 20 pups per litter). Despite this, Shepherd and Myers (2005) documented declines in N. bancroftii, to 2% (95% confidence intervals 0.5–5%) of its baseline abundance in 1972 in the Northern Gulf of Mexico, most probably caused by intense shrimp trawling. Similar declines were also documented in Narcine bancroftii in US trawl surveys and diver surveys off Florida (Carvalho et al. 2007).

Conservation Actions [top]

Conservation Actions:	There are no species specific conservation measures in place. Further surveys are needed to assess and monitor abundance. Research is also needed on the species’ biology and capture in fisheries. The development and implementation of management plans (national and/or regional e.g., under the FAO International Plan of Action for the Conservation and Management of Sharks: IPOA-Sharks) are required to facilitate the conservation and management of all chondrichthyan species in the region.

Conservation Actions:

There are no species specific conservation measures in place. Further surveys are needed to assess and monitor abundance. Research is also needed on the species’ biology and capture in fisheries.

The development and implementation of management plans (national and/or regional e.g., under the FAO International Plan of Action for the Conservation and Management of Sharks: IPOA-Sharks) are required to facilitate the conservation and management of all chondrichthyan species in the region.

Citation:	Carvalho, M.R. de & McCord, M.E. 2009. Narke japonica. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 19 May 2013.
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