Not just Shark
Pictures: Elasmodiver contains photos of sharks, skates, rays, and
chimaera's from around the world. Elasmodiver began as a simple web
based shark field guide 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.
There are now
more than 5000 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 accessed here:
Nurse
shark, Common nurse shark, Atlantic nurse shark.
Latin Name: Ginglymostoma
cirratum.
Family:
Ginglymostomatidae
Identification: Uniformly
brown or gray body, paling slightly towards belly. Two dorsal fins of almost
equal size close to tail. Head bulbous with small mouth. Mouth has a barbell on
each side. Tail narrow with a large upper caudal lobe and no distinct lower
lobe.
Size: 5 to
9ft max. 14ft.
Habitat: Found
in many environments including reef flats, sandy areas, lagoons, and mangroves.
From intertidal to 150ft.
Abundance: This
is the most commonly encountered shark on most Caribbean reefs. It can be
locally common from Florida to Brazil.
Distribution: On
the Atlantic coast of the Americas from Rhode Island to Brazil. Bermuda and the
Eastern Atlantic from Senegal to Gabon. Also in the Eastern Pacific from Baja
California to Peru.
Behavior: Nocturnal.
Sleeps under overhangs of reefs, or in mangroves during the day. Often found
sleeping in small groups. At night forages for spiny lobsters, crabs, octopus,
and sea urchins etc. May inhabit same area for many years.
Reproduction: Ovoviviparous.
Observations: On
one night dive, I observed a Nurse darting in and out of our flashlight beams,
possibly using the light for hunting but his agitated swimming suggested more
that we were intruding.
Photographs: Sail
rock, Grenadines, St Vincent (top). Tiger Beach, Bahamas (bottom).
Similar species:
The nurse sharks shares
its Eastern Atlantic range with the West African nurse shark – Ginglymostoma
brevicaudatum
Reaction to divers: During
day lies motionless unless closely harassed. Will bite if provoked. Nurse sharks
are opportunistic and become regular visitors to shark feeds.
Diving logistics: Nurse
sharks are extremely common sights in many areas of Florida and the Caribbean.
Until recently banned, Florida shark feeding dive boats out of Fort Lauderdale
and Boca Raton, were guaranteed Nurse watching experiences. The Sea Emperor
wreck off of this same coastline usually has a group of Nurses sleeping under
the bow. More remote places in the Caribbean such as Sail Rock in the Grenadines
usually have Nurses lying under every available overhang. This dive sight is
accessible using Dive Grenadines out of Union Island.