usa | world | animals | vocabulary | health | science | math | history


Electric rays (order Torpediniformes) are fish that have rounded bodes and a pair of organs capable of producing an electric discharge. This shock can vary between 8 volts and 220 volts, depending on the species. There are 69 species of electric ray in four families.


 


The ray can reach a total length of 140 cm and a weight of 41 kg. The body is round and gray with small black spots on the dorsal side. The two dorsal fins are located near the tail.


The Pacific electric ray (Torpedo californica) is a species of electric ray native to the eastern Pacific Ocean. The range of the species is from British Columbia, Canada to Baja California, Mexico, and possibly also other areas of the Pacific. The rays are found in kelp forests and on sandy bottoms, sometimes partially buried in the sand. It feeds on bony fish, primarily herrings and halibut. It can stun prey using electric discharges from its electric organ. The discharges can reach 50 volt and 1 kilowatt.

The blind electric ray, blind legged torpedo, or numbfish, (Typhlonarke aysoni), is a numbfish of the genus Typhlonarke, found around New Zealand from Cook Strait southwards on the continental shelf, at depths of between 100 and 900 metres. Its length is between 15 to 30 centimetres. It is a very small, poorly-known electric ray with the typical round body shape, small fleshy tail, one dorsal fin, and almost useless eyes. A large part of the front of the body is taken up with modified muscle organs that store up electrical charge and delivery it to stun prey when needed. This mechanism can also be used for navigation and prey detection in dark or murky water.

The blind electric ray is dark brown in colour, and is potentially vulnerable to fisheries activity since its known distribution coincides with major trawl fishery grounds. However, recent marine sanctuaries around New Zealand provide some safe havens. Its distribution and status is uncertain due to confusion with the similar oval electric ray, Typhlonarke tarakea. There is therefore inadequate information to make a direct, or indirect, assessment of its risk of extinction based on its distribution and/or population status.


Electric rays are ovoviviparous (bearing live young) and reproduce slowly with a doubling time estimated to be between 4.5 and 14 years.


Perhaps the most known members are those of the genus Torpedo, also called crampfish and numbfish, after which the device called a torpedo is named. The name comes from the Latin "torpere", to be stiffened or paralyzed, referring to the effect on someone who handles or steps on a living electric ray.

The torpedo rays have been used as model organisms for molecular biology research, because of the high natural abundance of some proteins in its electrical organs. A notable example is acetylcholinesterase.

 

All text is available under the terms of the GNU Free Documentation License

   
 


 Kingdom: Animalia

 Phylum: Chordata

 Class: Chondrichthyes

 Superorder: Batoidea

 Order: Torpediniformes