Featured Elasmobranch – Pacific Torpedo Ray
Category : Featured Elasmobranch
Pacific Torpedo Ray
Torpedo californica Ayres, 1855
Family Torpedinidae (Electric Rays)
Identification: A medium sized, soft, flabby bodied ray with an oval disc. The dorsal surface is smooth with a visible kidney-shaped electric organ. Teeth are small, with a single smooth-edged cusp. First dorsal fin is nearly twice the size of the second, and the tail is short and stocky. Color a uniform dark gray to bluish or brown above, occasionally with small black spots; ventral surface is lighter.
Size: Maximum reported length 137 cm for females and 92 cm for males. Size at birth is 18-23 cm.
Distribution: The Pacific torpedo ray is endemic to the eastern North Pacific ranging from Mazatlan, Mexico to northern British Columbia.
Habitat: Typically found on sandy bottoms, around rocky reefs, and near kelp beds from 3 to 30 m deep, although they have observed down to 200 m. They are known to occur epipelagically over water up to at least 3,000 m deep. These rays prefer water temperatures between 500 to 600 degrees Fahrenheit.
Biology: The reproductive mode is viviparous without yolk-sac placenta. Litters of up to 20 have been reported. Females mature at about 73 cm and males at about 65 cm total length. There does not appear to a defined birthing season, but females are believed to give birth every 12-24 months. These rays live to at least 16 years and possibly up to 24 years. The diet includes mostly teleosts and invertebrates especially cephalopods.
General interest: Occasionally taken as by-catch, torpedo rays are taken in small numbers for the purpose of biological and medical research. As with most members of this group of electric rays, Pacific Torpedo rays can discharge a powerful electric shock of 45 volts or more, strong enough to knock down a grown adult.
By David A. Ebert
Pacific Shark Research Center
Moss Landing Marine Laboratories
8272 Moss Landing Road
Moss Landing, CA 95039