Tetronarce californica (Ayres, 1855)
Pacific electric ray
Tetronarce californica
photo by Canadian Museum of Nature, Ottawa, Canada

Family:  Torpedinidae (Electric rays)
Max. size:  140 cm TL (male/unsexed); 137 cm TL (female); max.weight: 41 kg; max. reported age: 16 years
Environment:  demersal; marine; depth range 0 - 906 m
Distribution:  Eastern Pacific: Dixon Entrance, British Columbia, Canada to Sebastian Vizcaino Bay, Baja California, Mexico. Electric rays off Peru, Chile, and Japan may belong to this species (Ref. 2850).
Diagnosis:  Gray with scattered black spots dorsally, no ocelli. 1st dorsal fin much larger than 2nd. Spiracle margin smooth and without papillae.
Biology:  Found on the outer continental shelf, around rocks, in kelp beds, over fine sand bottoms or buried in sand. Solitary, nomadic, and can remain suspended in the water with minimal swimming (Ref. 12951). Feeds on bony fishes, mainly herrings and halibuts. Ovoviviparous (Ref. 50449). Produces litters of up to 17 pups. Males reaches maturity at ca. 65 cm TL, females at ca. 73 cm TL (Ref. 114953). Attacks their prey from the substratum by day and actively forage at night with the aid of its electric organ discharge or EOD (Ref. 10011). The EOD of a large individual was measured at 50 V; with a low internal organ resistance the power output exceeded 1 kW (Ref. 10480). Aggressive when provoked but no human has yet been injured by the electric shock (Ref. 2850). Does not do well in aquariums (Ref. 12951).
IUCN Red List Status: Least Concern (LC); Date assessed: 05 January 2015 Ref. (130435)
Threat to humans:  other


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