Not just Shark
Pictures: Elasmodiver contains photos of sharks, skates, rays, and
chimaera's from around the world. It began as a simple web based
field guide to help divers find the best places to encounter
different species of sharks and rays but it has slowly evolved into
a much larger project containing information on all aspects of shark
diving and photography. There are now more than a thousand shark
pictures and sections on shark evolution, biology, and
conservation. There is a large library of reviewed shark books, a
constantly outdated shark taxonomy page, a monster list of shark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 accessed here:
If you're looking for a
broader range of marine life pictures the following links represent
a new area that contains pictures on other marine organisms and on
marine habitats. This expansion of Elasmodiver is in its first
stages but will eventually include pages on everything from sea
stars to nudibranchs. Creating this portal will take time and for
now it consists of a token offering of fish pictures. Please return
regularly to enjoy the progress.
Identification:
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.
Size:
Maximum
length 3.3m.
70 to 87cm at birth.
Habitat:
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
ocean.
Abundance
and distribution: Circumtropical.
Behavior:Arching back threat display recorded.
Reproduction:
Viviparous.
Litter size 2 - 14.
Observations:
Often seen with Scalloped Hammerheads at sea mounts.
Photographs:
Galveston, Texas.
Similar species:
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.
Reaction to divers:
Reactions vary depending on size, location, and
style of interaction. In Galveston, Texas the silky sharks tend to be small and
therefore hard to approach where 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.
Diving
logistics: Probably the best place to interact
with Silky Sharks is Cocos Island (Costa Rica) where hundreds of Silkies
aggregate. These sharks are visible on practically every dive and they also hang
around the dive boat at night. The Undersea Hunter runs week long live aboard
trips to Cocos each week from Punta Arenas.
Other diving locations submitted by
readers:
Further
reading:
Reef
Sharks and Rays of the World. Scott W. Michael. Sea Challengers.
Sharks
and Rays - Elasmobranch Guide of the World. Ralf M. Hennemann. IKAN.
The
Shark Watcher's Handbook - Mark Carwardine & Ken Watterson. Princeton
University Press.
