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
Long pointed snout. Interdorsal ridge present. Low rounded first dorsal fin
originates behind pectoral axis. Small second dorsal with long free rear tip.
Pectoral fins long with dusky or black tips on underside. Second dorsal much smaller than first.
Dorsal body coloration olive brown with distinctive reflective sheen that gives
this shark its common name.
70 to 87cm at birth.
Prefers offshore islands, sea mounts, drop offs and vertical rocky or coral
reefs. To 500m depth.One of three species (also
including Oceanic Whitetip and Blue Shark) of sharks that patrols the open
and distribution: Circumtropical.
Behavior:Arching back threat display recorded.
Litter size 2 - 14.
Conservation Status: Listed as VULNERABLE by the IUCN. The Silky
Shark is the second most caught species of shark globally, after the Blue Shark
(Prionace glauca) (Oliver et al. 2015). The Silky Shark is
both targeted or caught as incidental (bycatch) by longline fisheries and purse
seine fisheries (especially those using drifting fish aggregating devices [FADs])
as well as by artisanal fisheries. FADs are made of a floating object and nets
that lie vertical in the water column to attract schools of fish. The Silky
Shark, as well as other species, is easily entangled in the nets; and there have
been large increases in the use of FADs since 1996 (Leroy et al. 2013).
Whether they are targeted or an incidental catch, the Silky Shark is often
either retained for its meat and fins where regulations allow, or released with
high mortality rates apparent in the tropical purse seine fisheries (Hutchinson et
al. 2015). Total catches of the Silky Shark reported to FAO are mainly from
Sri Lanka (Western Indian Ocean) with the FAO catch less than 4,000 tonnes (t)
from 2005-2009 before doubling in 2010 and 2011. Catches then decreased to
~5,000 t in 2012 and 2013 (FAO 2015).
The Silky Shark was found to represent at least 3-4% of the fins auctioned in
Hong Kong, the world's largest shark fin trading centrethe third highest after
Blue Shark and Hammerhead Shark (general) (Clarke et al. 2006a)and
Hong Kong is thought to make up more than half of the global shark fin trade
(Clarke et al. 2004, 2006b). Silky Shark fins are valuable to the
trade, although they are not one of the highest value fin types (S. Clarke,
Top - Cat Island, Bahamas. Bottom -
Although the silky shark is superficially similar to many other carcharinid
species, it is easily recognizable by its shiny skin and low rounded first
dorsal. Some older silky sharks may lose their lustre. At that point they may be
confused with other species e.g. dusky sharks Carcharhinus obscurus.
Duskies have a higher, more pointed first dorsal and a slightly blunter snout.
Reaction to divers:
Reactions vary depending on size, location, and
style of interaction. In Galveston, Texas the silky sharks tend to be small and
hard to approach. At Cat Island in the Bahamas, they are more used to divers and
allow a close approach. At offshore islands in the Eastern Pacific such as at Cocos Island in Costa Rica, there are so
many large and aggressive silkies that at times it is not safe to enter the
water as they may bump and possibly bite divers.
At Cat Island in the Bahamas the silkies are becoming used to divers and freely
swim around them.
Silky sharks are common at nurmerous locations around the world. Around the
Eastern Pacific islands such as Socorro and Cocos, they can be seen feeding on
baitfish on offshore seamounts.
During oceanic whitetip shark dives at
Cat Island in the Bahamas, silkies allow divers to approach within
touching distance. Big Fish Expeditions runs
shark diving trips to Cat Island
Jardin de la Reina in Cuba is another reputedly good
place to find them.
Rigby, C.L., Sherman, C.S., Chin, A. & Simpfendorfer, C. 2017. Carcharhinus
The IUCN Red List of Threatened Species 2017: e.T39370A117721799. http://dx.doi.org/10.2305/IUCN.UK.2017-3.RLTS.T39370A117721799.en. Downloaded