Featured Elasmobranch-Vermiculated Electric Ray

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Featured Elasmobranch-Vermiculated Electric Ray

February 2012

Vermiculated Electric Ray

Narcine vermiculatus (Breder 1928)

Family Narcinidae

IdentificationThe coloration of this species is striking. The dorsal side is chocolate brown with many irregular white transverse blotches, and the caudal has 2 irregular white bars.  Each dorsal fin has a white central spot, and the ventral side is white.  The body is an elongated oval disc with soft edges, and the pectoral fins overlap the front origin of the pelvic fins.  Two large, similar sized dorsal fins are present, and the tail is thick with a distinct caudal. They have spiracles that are larger than their small eyes. There is a large kidney-shaped electric organ behind the eye.  The mouth is tubular, and the teeth are mostly exposed when it is closed.

Size – Although the species is reported to reach a maximum size of 60 cm TL, individuals greater than 30 cm have not been observed.  Size at maturity (see biology section) would also suggest that maximum size is less than 60 cm.

Distribution – It is found in the eastern central Pacific, from southern Sonora, Mexico, to Costa Rica, and disjunct in the southwestern Gulf of California.

HabitatThis species is usually found on soft bottom habitats between about 7 and 50 meters in depth, although they have been reported at depths up to 100 meters.

Biology – There is limited biological information for this species.  Individuals of around 5 cm TL have been found to be free swimming, with faint yolk-scars.  Males and females reach maturity around 20 cm TL.  It has been found to feed on benthic worms, crustaceans, gastropods and bivalves, and some bony fish.

General Interest – This species is listed as Near Threatened by the IUCN Redlist Assessment.  There is heavy trawl pressure over its range, and it is taken as bycatch in artisanal and industrial shrimp trawl fisheries off Mazatlan.  In addition, aquaculture developments may negatively impact its habitat.  The exact range of this species is not known, but it is fairly restricted, and a decline in abundance is suspected due to threats to the species

Written By: Kelley Andrews