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a large library of reviewed shark books, a constantly outdated shark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 nudibranches. 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. Slender body. Dorsal coloration is uniformly grey to copper
brown above (without scattered
white spots). Interdorsal ridge present. First dorsal starts directly
above or just in front of free rear tip of pectoral
fins. Second dorsal very low with long free rear tip.
Pectoral fins with thin light/white posterior margin. White line also on
posterior margin of lower caudal
fin, sometimes inconspicuous. Upper caudal margin dusky or black. Long labial furrows.
Size:
At birth 31-34cm. Males mature at 93-96cm. Females mature at 83-95cm. Maximum
size at least 129.5cm but possibly 154cm.
Habitat:
Recorded as inhabiting depths from
Intertidal to 27m but long liners in the Gulf of Mexico
regularly fish for Pacific sharpnose sharks with bottom hooks set at 80m. Mostly
over muddy substrate.
Distribution:
Eastern Pacific from
Southern California to Peru including the Sea of Cortez.
Abundance:
Fairly abundant in the Sea of Cortez but heavily fished. Longline fishermen have
reported significant declines. Anecdotally, in 2009 on one trip with shark
fishermen from Mulege 1400 hooks yielded seven small sharpnose sharks compared
to more than 1700kg in one day 20 years ago. IUCN not evaluated.
Behavior:Little
known
Reproduction:
Placental
Viviparity.
Litter size 1 to 12. Unlike in the Atlantic sharpnose shark no correlation has
been found between the litter size and size of the female. Average litter size
7.1.
Diet:
Small demersal fishes, cephalopods and crustaceans.
Photographs:
Sea of Cortez, Mulege, Baja,
Mexico. These images were taken with the help of artesanal
longline fishermen aboard a small wooden panga about 4km from shore. These are
probably the first images of live, free swimming Pacific sharpnose sharks.
Similar species:The Pacific sharpnose shark can be positively identified by
location because there are no other sharpnose sharks along the Pacific coast of
the Americas. Conceivably it is possible that some Caribbean and/or Brazilian
sharpnose sharks have made their way through the Panama Canal. This has been
documented in a number of species including some elasmobranchs.
Reaction to divers:
Rarely if ever encountered by scuba divers due to their timidity and preference
for turbid water and sand/mud bottoms.
Diving
logistics:
See reaction to divers above. Elasmodiver would be very interested in hearing
about any natural encounters.
Other diving locations submitted by
readers:
Further
reading:
Observations on the Biology of the Pacific Sharpnose Shark (Rhizoprionodon
logurio, Jordan and Gilbert, 1882) Captured in Southern Sinaloa, Mexico.
Marques-Farias, Corro-Espinosa & Castillo-Geniz 2005.
