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
on trailing edge of dorsal fin (sometimes indistinct or absent). All other fins with dusky
or black trailing edges. Distinct black margin along entire length of
trailing edge of caudal fin. Grey upper body. Ventrum white. Pectoral fins
proportionately long and falcate. Snout long and broadly rounded. No
Maximum length 2.3 - 2.5m. Size at birth 45-75cm.
Drop offs adjascent to coral reefs, atoll passes, reef flats, leeside of coral
islands, lagoons and anywhere within its range where strong currents are common.
The grey reef shark is a particularly abundant species in the passes of coral
atolls. 0 -140m. More common below 10m.
Indo-west Pacific from Madagascar to
southeast Asia, Northern Australia, French Polynesia and Hawaiian Islands.
An extremely social species that congregates by day in current swept areas such
as atoll passes (see image below). The grey reef shark is well known for its
aggressive posturing when agitated: back arching, pectoral fin lowering
and exaggerated side to side head movements while swimming.
Viviparous. Litter number 1 - 6. Around one year gestation. Grey reef sharks
maturity after 7-7.5 years.
Near Threatened. According to the IUCN,
this shark shows high site fidelity and some local populations have been
severely depleted by modest fishing pressure, as has been shown off Hawaii (Wetherbee
et al. 1997). Very marked declines of sharks, including Grey Reef Sharks, have
been reported in the Chagos Archipelago (Indian Ocean) between the 1970s and
1996. Shark numbers here were reduced to only 14% of the numbers found in the
1970s (Anderson et al. 1998). The quality of its coral reef habitat is
threatened in many parts of the world.
Fakarava, French Polynesia.
Similar species:The silvertip Shark (Carcharhinus ambimarginatus) has similarly coloured dorsal fins
but all other fins have white margins. The grey reef shark may also be confused
with the dusky shark, Galapagos shark and a number of other rarely seen
carcharhinids that share its indo Pacific range.
Reaction to divers:
Grey reef sharks usually keep their distance even when in large aggregations
unless food is introduced.
There are many locations where grey reef sharks can be encountered by
divers but some of the best locations are atoll passes in French Polynesia.
Perhaps the best of the best is the Tumakohua Pass on the south end of Fakarava
Atoll. At this location upwards of 500 sharks can be seen during a drift through
the pass. Other species that you are likely to encounter on the same dive
include silvertip sharks, blacktips, reef whitetips and indo-Pacific blacktips.
There are a handful of dive shops on Fakarava that dive the pass.
Reef Sharks and Rays of the World. Scott W. Michael. Sea
Sharks and Rays - Elasmobranch Guide of the World. Ralf M.