In the Bohai Bay, a fleet of ocean-going vessels arrived in the East China Sea to catch fish during the fishing season. While troubleshooting underwater issues, a technician encountered a peculiar situation: upon diving, he accidentally touched something, and suddenly his limbs went numb, and his whole body trembled. Local fishermen informed them that this was the work of an electric ray, a type of cartilaginous fish that can generate electric shocks.
Interestingly, the ability to produce electricity is not exclusive to electric rays. Over 500 species of fish have been discovered with 'generators' in their bodies that can emit electric currents. The largest electric ray can discharge electricity up to 150 times per second, with voltages reaching as high as 220 volts. The African electric catfish can produce a voltage of 350 volts, enough to kill small fish and even incapacitate fishermen. The electric eel from South America is the most powerful electric fish, capable of generating up to 800 volts. It has been calculated that the combined output of 10,000 electric eels could power an electric vehicle for several minutes.
So, how do these electric fish generate electricity?
They possess unique electric organs within their bodies that can create high voltages externally. These organs can originate from muscle tissues in the gills or tail, and some come from eye muscles and glands. The electric organs of the electric eel are found along the sides of the tail's vertebrae, shaped like elongated prisms. In contrast, the electric ray's electric organs are located on either side of the head and abdomen, resembling two flat kidneys made up of numerous honeycomb-like cells.
During a discharge, the electric ray can emit a voltage of 60 to 70 volts. With continuous discharges, the voltage can reach 100 volts, and the largest individuals can discharge around 200 volts with a power of 3 kilowatts, enough to incapacitate fish and shrimp in the water, serving as their food. Additionally, discharging electricity is a way for electric fish to evade threats and protect themselves.
