Not just a
huge collection of
Elasmodiver.com contains images of sharks, skates, rays, and a few
chimaera's from around the world. Elasmodiver began as a simple web
to help divers find the best places to encounter the different
species of sharks and rays that live in shallow water but it has
slowly evolved into a much larger project containing information on
all aspects of shark diving and shark photography.
now more than 10,000 shark pictures and sections on shark
evolution, biology, and conservation. There is a large library of
reviewed shark books, a constantly updated shark taxonomy page, a
monster list of shark links, and deeper in the site there are
numerous articles and stories about shark encounters. Elasmodiver is
now so difficult to check for updates, that new information and
pictures are listed on an Elasmodiver Updates Page that can be
The Japanese sleeper ray has
pair-shaped body disc. Reddish-brown to chocolate brown dorsum, often with a few scattered dark or
light spots. Ventrum lighter brown. One rounded dorsal fin positioned posterior
to pectoral fins. Tail thick, short and dorsally compressed with
a lateral skin fold. High caudal fin, roughly triangular with no definition between upper and
lower caudal lobes. Eyes small. Spiracles also small but with a prominent, raised rim
that projects above the head. Groove around mouth.
Maximum length 40cm.
Usually found on sand near rocky reefs from 12 to 23 meters deep.
Northwest Pacific Ocean. Southern Japan, North and South Korea,
Mainland China, Taiwan and Hong Kong.
Behavior:The Japanese sleeper ray spends most of its time buried
in the sand
(see below). May incapacitate some prey by discharging its electric organs but
probably mostly used for defense. Electric organs can emit 30-80v. Major
predators include the blotchy swell shark.
Litter number up to 5.
as vulnerable by the IUCN. 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
Citation: Carvalho, M.R. de & McCord, M.E. 2009. Narke
japonica. The IUCN Red List of Threatened Species. Version 2014.3. <www.iucnredlist.org>