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a large library of reviewed shark books, a constantly outdated shark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:
Supraorbital
crests (brow bones) moderately high. Small dark spots on tan or grey body (spots
occasionally absent). Large, blocky, pig-like head. Dorsal spines present,
terminating well below tips of dorsal fins. Pectoral fins large. Jaw contains
anterior, pointed, clutching teeth andrear
molars. Dentition changes with age (adults have more prominent molars).
Size:
Maximum
length 120cm.
Habitat:
Rocky
reefs and Kelp forests. Juveniles often in open sandy areas.
Abundance
and distribution: Central California
to the Sea
of Cortez
and possibly South
America.
Behavior:
Nocturnal.
Hides in crevices or caves during the day venturing out to forage at night. May
swim freely but is usually seen sluggishly moving along the bottom on its
muscular pectoral fins. Hunts for Urchins, crabs, worms, anemones, and bony
fishes.
Reproduction:
Oviparous.Lays a distinctive auger shaped egg case with two threadlike filaments
extending from one end. Egg hatches in 7 to 9 months.
Observations:
I
have a friend in Avalon who regularly encounters Horn shark egg cases and places
them in his toilet cistern until they hatch safely. He then releases them back
into the ocean giving them an edge on the rest of the food chain.(Avalon utilizes salt water in its toilets to save its limited fresh water
supply).
Photographs:
Avalon,
Catalina
Island, California.
Similar
species: Mexican
bullhead shark - Heterodontus mexicanus,
Cortez bullhead shark – Heterodontus sp.
Both sharks potentially share the south range of the California Horn shark.
Reaction
to divers: Easily
approached. Remains motionless unless molested. Caution should be taken around
dorsal spines.
Diving
logistics: Most
easily observed whilst night diving. Catalina offers an excellent opportunity to
encounter this shark. Air and equipment can be obtained on the pier in Avalon
for shore diving purposes. Head out on the road past Lovers Cove South of town
and enter from the beach. This is a long hike if you’re wheeling your gear
along in a rented cart. Small Horn sharks are usually present in around 30ft of
water. The DivePark
at Casino Point right in Avalon may also be a reasonable place to look at night
but this area gets too much traffic during the day for reliable sightings.
Other
diving locations submitted by readers:
Further
reading:
Sharks,
Rays, and Chimaeras of California.
David A. Ebert. University
of California
Press.
Coastal
Fish Identification - California
to Alaska.
Paul Humann. New World Publications Inc.
Reef
Sharks and Rays of the World. Scott W. Michael. Sea Challengers.
Sharks
and Rays - Elasmobranch Guide of the World. Ralf M. Hennemann. IKAN.
