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constantly outdated shark taxonomy page, a monster list of shark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:
grey to olive brown body with very little mottling. Ventral surface marginally lighter than
dorsal surface. Skin quite smooth and covered in mucus. Head and snout
vertically depressed. First dorsal fin length at least twice
height with long free rear tip. Dorsal fins slightly dusky on
leading edges. Dorsal fin spines dark. Fin spine lengths are about 1/3rd length of leading edge of
dorsal fin. No white margins on posterior
edges of dorsal and caudal fins. Upper caudal lobe deeply
notched. Lower caudal lobe moderately long but very weakly defined (no
posterior caudal notch). Eyes
very large and green with black rims.
Size: Maximum
length 160cm male, 145cm female. size at birth 30-42cm.
Habitat:
Continental shelves and slopes from 50-1440m but rarely shallower than 200m. In
the Bahamas, gulper sharks are more frequently caught around monumentation than
on flat substrate.
Abundance and distribution:
A wide ranging species. Eastern Atlantic - France to West and possibly South
Africa (including the Mediterranean Sea). Western Atlantic - Gulf of Mexico to
northern South America. Indian Ocean - Madagascar, Sudan and Western Australia.
And Western Pacific south of Japan. Not recorded in the Eastern Pacific.
IUCN Red List
Status: Near Threatened. Believed to have the lowest reproductive potential of
all elasmobranch species; its reproductive biology is characterized by a late
onset of maturity (12 to 16 years in females), only one pup per litter and a
two-year gestation period with occasional resting periods. This makes it
extremely vulnerable to overexploitation and population depletion. Despite a
lack of data for certain regions within its geographic range, this species is
globally assessed as Vulnerable on the basis of its limiting life history traits
and the global increase in unmanaged fishing effort to exploit deeper waters.
Heavily fished and
caught as bycatch in the Northeast Atlantic, the Northwest Pacific and other
regions. Targeted for liver oil and meat.
Behavior:
Not known.
Diet: small bony fishes,
squid and crustaceans.
Reproduction:
Ovoviviparous. One pup per litter. Gestation period 2 years with resting periods
inbetween. Maturity probably occurs around 60-80cm.
Observations: Mortality
among captured specimens is high suggesting that Taiwan gulper sharks do not
respond well to temperature changes and stress.
Photographs:
Cape Eleuthera, Bahamas. Images captured during a deep shark survey conducted by
Edd Brooks of the Cape Eleuthera Institute.
Similar species:
Because the Taiwan Gulper Shark is a broad ranging species, it overlaps with
many other species of gulpers. In the Bahamas it is found with common gulper
sharks which are thicker bodied and have a less depressed head and a more distinct
caudal posterior notch.
Reaction to divers:
Not encountered by divers.
Diving logistics:
Not applicable.
References:
Citation:
Guallart, J., Serena, F., Mancusi, C., Casper, B.M., Burgess, G.H., Ebert, D.A.,
Clarke, M. & Stenberg, C. 2006. Centrophorus granulosus. In: IUCN 2011. IUCN Red
List of Threatened Species. Version 2011.1. <www.iucnredlist.org>. Downloaded on
19 October 2011.
