During the spring and summer seasons, we see an increase of cartilaginous fish populations in the SF Bay. This week, MSI is featuring the Pacific electric ray
The Pacific electric ray (Torpedo californica) is found only along the west coast of the United States. Typically found in sandy bottoms, rocky reefs, and kelp beds, we will occasionally catch them aboard the R/V Robert G. Brownlee in the San Francisco Bay estuary. Essential characteristics of this species are their round mobile body that has a very large first dorsal (top) fin and kidney shape electric organs on the side of its head. If provoked these species can control a charge causing numbness in humans and stun prey. This charge can measure up to 50 volts!
Like most Chondrichthyes (cartilaginous) fish, they possess pores (ampullae of Lorenzini) that sense magnetic fields given off by other living organisms. Like our local leopard sharks, these rays are ovoviviparous. Ovoviviparous is the process in which the embryos (feeding on the nutrient in the yolk sack) develop inside eggs that are held within the mother. The mother can produce a litter of offspring (approximately 20). Offspring start around 7 inches, these unique species can grow up to 36 inches (males) and 54 inches (females) and live as long as 24 years.
Prepared by: Hayley Usedom
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Resources and References:
Tough, Shannon. Torpedo califonica. Ichthyology Collection. Dickinson Hall Florida Museum. University of Florida. 2018. http://www.flmnh.ufl.edu/fish/Gallery/Descript/Peray/Peray.html
Pacific electric ray. Animal Guide. Animals & Exhibits at the Monterey Bay Aquarium. http://www.montereybayaquarium.org/animal-guide/fishes/pacific-electric-ray
Allen, M.J. and G.B. Smith, 1988. Atlas and zoogeography of common fishes in the Bering Sea and northeastern Pacific. NOAA Tech. Rep. NMFS 66, 151 p. (Ref. 6793) http://fishbase.org/summary/2552
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