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WHAT IS ELASMODIVER?

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 10,000 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:

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Shark picture - green sawfish

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SHOVELNOSE GUITARFISH

View all available Shovelnose Guitarfish Pictures in the Shark Pictures Database

Common Names: Shovelnose Guitarfish, Californian Guitarfish, Shovelnose Ray.

Latin Name: Rhinobatos productus

Family: Rhinobatidae

Identification: Body disc longer than width. Snout pointed with slight concavity before rounded tip. Body tapers into broad tail topped by two dorsal fins of equal size. Thorns (enlarged denticles) around eyes and extending in a single row along centre line of back and tail. Well developed caudal fin roughly triangular with indistinct lower lobe. Dorsum color olive to sandy brown with vague darker blotches. Ventrum pale.

Size: Maximum length 170cm. 15-23cm at birth

Habitat: Intertidal Inshore waters and estuaries to 13m but recorded at 91m. On sand or mud bottoms. Occasionally in sea grass beds.

Abundance and distribution: Eastern Pacific from central California (San Fransisco) to the Sea of Cortez. May be locally abundant forming large aggregations.

Behavior: Lays partially buried in sand when not foraging for food. Hunts for benthic invertebrates including poychaete worms, clams, amphipods, crabs and shrimp. Adults also consume some bony fishes. Swims by using powerful caudal fin.

Reproduction: Guitarfishes are ovoviviparous (yolk sac viviparity). Female Shovelnose Guitarfish give birth in shallow sandy bays in late spring/summer. El Nino years tend to induce earlier reproductive cycles. Gestation lasts about 12 months after which up to 28 young may be born.

Observations:

Photographs: La Jolla Shores, San Diego, California.

Similar species: The Speckled Guitarfish (Rhinobatos glaucostigma) from southern Baja and further south can be identified by a scattering of small light sots over its back. The Banded Guitarfish (Zapteryx exasperata) which ranges from southern California south, has a more rounded anterior margin and darker and more distinct blotches across its snout and much of its body.

Reaction to divers: Generally skittish and difficult to approach. Although these guitarfish usually move away when approached there is one record of a diver being bitten by a guitarfish that was disturbed while chasing a female at La Jolla Cove.

Diving logistics: Shovelnose Guitarfish move in and out of bays in southern California during the summer and fall. A promising but non guaranteed spot to snorkel with them is off the beach at the Marine Room at La Jolla. In late summer they can be so thick that as you approach them their mass exodus brings the visibility down to almost zero. 

Other diving locations submitted by readers:

Further reading:

Sharks, Rays, and Chimaeras of California. David A. 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.

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