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constantly outdated shark taxonomy page, a monster list of shark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.
Bat Ray, California Bat Ray, Californian Eagle Ray.
Latin Name:
Myliobatis californicus
Family: Myliobatididae
Identification:
Pectoral fin tips rounded. Subrostral lobe (beak) short and rounded. Small
dorsal fin positioned just behind the posterior edge of the pelvic fins.
Dorsum uniformly brown, olive, or black. Albinism reported but rare. Disc width
more than 1.5 x length. Long slender whip-like tail with elongated finely
serrated tail sting.
Size: Maximum disc width 1.8m.
at birth 20-31cm.
Habitat:
Usually found in sandy or muddy bays
and less frequently on rocky reefs and in kelp forests. Intertidal To about 50m
but Bat Rays will migrate over deeper water when traveling between islands.
Abundance and distribution:
Endemic to the eastern Pacific from Yaquina Bay in northern Oregon to the Gulf
of California. Common along the Californian coastline and around the Channel
Islands. Maintains a small home range
Behavior:
Solitary or schooling. Large schools made up of thousands of bat rays have been
seen around the Channel Islands. Bat Ray schools in Baja may contain Spotted
Eagle Rays where as northern populations may school with Smoothhound Sharks.
Individuals are
sometimes found resting on the sand in excavated depressions.
Diet:
Feeds by pushing its snout through the mud or sand to find invertibrates. Also
flexes its pectoral fins while on the substrate to create enough suction to pull
sand away exposing prey animals. Diet includes clams, worms, abalone. oysters,
snails, shrimps, crabs, and bony fishes.
Reproduction: Ovoviviparous.
Observations:
California Bat Rays can sometimes be located by following clouds of floating
silt and sand upstream until the animal is found exposing prey.
Photographs: Catalina Island,
California.
Similar species:
Reaction to divers: Difficult
to approach. Skittish. Will move away upon sensing a divers approach. Tactics to
get near include swimming slowly along the bottom in a non-threatening way i.e.
without erratic movements and at an indirect angle.
Diving logistics:
California Bat Rays are often encountered while diving in the kelp forests
around Catalina Island. Two dive companies in Avalon (the only town) can arrange
charters to the best sites but they cannot guarantee that Bat Rays will show up.
Shore divers in Southern California
regularly see Bat Rays along the shoreline just outside the surf. Try to get up
to date advice from locals on the specifics of where and when to plan a dive.
The beach divers at La Jolla Shores find Bat Rays in the presence of Leopard
Sharks during the summer and fall.
Other diving locations submitted by readers:
Further reading:
Sharks, Rays, and Chimaeras of California.
David E.Ebert.
Reef Sharks and Rays of the World. Scott W. Michael. Sea Challengers.
Sharks
and Rays - Elasmobranch Guide of the World. Ralf M. Hennemann. IKAN.
