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constantly outdated shark taxonomy page, a monster list of shark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 of elasmodiver.com that contains pictures of
other marine organisms and of marine habitats. This expansion of
Elasmodiver is in its first stages but will eventually include pages
on all types of marine mammals, bony fishes and marine invertebrates
as well as coastal habitats, reefscapes and other imagess relating
to the ocean. Please return regularly to enjoy the progress.
Identification:
Enormous size (the whale shark is the world's largest fish). Body
scalloped (with two distinct ridges running from behind head along each flank
into caudal fin. Pattern of white spots and indistinct lines on grey dorsum.
Ventrum white or pale. First dorsal large. Caudal large. Mouth terminal and
often open when observed feeding on plankton.
Size:
Maximum
length 18m (unconfirmed) reliably to 16m.
Habitat: Pelagic. Whale sharks come into reef areas when
food supply is abundant e.g. during coral spawning.
Abundance
and distribution: Circumtropical
except in the Mediterranean Sea.
Behavior: Usually
seen swimming with mouth agape in feeding mode. Little is known about the Whale
shark's biology, reproductive behaviour or migratory patterns.
A whale shark swims along with mouth agape to collect plankton
Reproduction:
Ovoviviparous. Previously thought to be oviparous due to an eggcase containing a
Whale shark embryo dredged from the bottom of the sea. This perception
changed in 1995 when a Taiwanese fishing boat harpooned an 8m female containing
300 embryos. Whale sharks have been observed at Ningaloo performing figure 8
maneuvers while nose to tail. It has been speculated that this may be some form
of courting behavior.
Photographs:
Ningaloo Reef, Western Australia.
Holbox Island, Mexico.
Similar
species: Due to their size and
distinct color patterns, whale sharks are unmistakable animals. I have heard
people refer to Basking Sharks as whalesharks
but there is no resemblance other than size and feeding habits.
Reaction
to divers: Whale sharks generally move away from the noise created
by scuba bubbles and from physical contact but they usually tolerate snorkelers
and free divers well. Getting too close to a whale shark
often causes it to dive and 'riding' sharks (holding onto the dorsal fin) interferes with their natural behaviour and should be discouraged
even if local rules are very liberal.
Diving logistics: Operators
in many places around the world run
Whale shark encounters. Some use spotter planes while others rely on the sharks
returning to well known feeding sites. Ningaloo Reef encounters are very
predicable and the customers generally get a few sharks each day during the
right season. For more information on Ningaloo go to the
Exmouth / Ningaloo Whale Shark Encounters
page in the Shark diving hotspots
section of Elasmodiver.
Another great place to see
whale sharks is Holbox Island which is norh of the Yucatan Peninsula in Mexico.
I have encountered more than 100 whale sharks at this spot in one week. The
visibility tends to be poor but the sheer number of sharks makes up for it. More
info on this encounter can be found on the
Holbox Island Whale Shark
Encounter page.
Whale sharks seasonally
congregate off the coast of Mozambique where they have been filmed attacking
bait balls.
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.
