Featured Elasmobranch – Ocellated Electric Ray

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Featured Elasmobranch – Ocellated Electric Ray

Ocellated Electric Ray

Diplobatis ommata (Jordan & Gilbert, 1890)

Order Torpediniformes

Identification: An electric ray with a large black ocellated spot in the center of its disc, which is about equal to its snout length; a dark spot centered by a pale spot, and surrounded by a thin pale circle.  The rest of the body is mottled and spotted with different shades of brown. The spiracle is smaller than the eye, and is fringed by 10-12 papillae.

Size: Maximum total length is about 25 cm.

Distribution: Endemic to the Eastern Pacific from the Sea of Cortez, Mexico to Ecuador.

Habitat: Occurs as shallow as 2 meters to as deep as 94 meters. It lives on both sandy and rocky bottom habitats, and often partially buries itself in sand.

Biology: Very little known other than this species is nocturnal and solitary, and feeds on small crustaceans, worms, and fishes. It has organs in its pectoral fins that emit an electric field and can be used for stunning prey.

General Interest: This species is not targeted by fishermen, but is commonly caught as bycatch by shrimp trawlers.  Very little is known about this species’ biology, which makes it potentially vulnerable to over harvesting due its restricted distributional range, heavy trawl fishing where it occurs, incidental capture in trawl fisheries, and a lack of information on its abundance and population size. It is currently listed as a “Vulnerable Species” under the IUCN Red List of Threatened Species. More work is needed to understand how old these rays live, how quickly they mature, how frequently they produce young, and how fecund they are.

By: Will Fennie

Ichthyology Lab

Moss Landing Marine Laboratories