Electric Eel

The electric eel ( Electrophorus electricus ) is a Poisson which in spite of its name does not belong to the family of the Anguille S but to the Gymnoptidae (but some classify it in a family with share: Electrophoridae).

It is a fresh water fish which one meets in the north of the South America of the basin of the Orénoque to that of the the Amazon.

It is a fish which resembles the true eels and which can reach up to 2,5 m length and weigh 20kg.

Electric body

It has the effect of having electric bodies (electric plate) in the posterior part of its body. The latter can reach 40 % of its mass. It is able to send electric shocks from 500 to 600 volts, some of its discharges reached a record of more than 800 volts under 2 amps which even if they cannot kill an human being are very dangerous (electrification). Its skin forms a protective coating against its own discharges. They use these discharges to be defended or as means of predation. They use also weaker and slower electric shocks to be directed in muddy water, and to find sexual partners. The period of reproduction takes place between September and December. The gymnote was very useful for research in neuroscience gràce for the great concentration in receivers with the Acétylcholine in the electric plates.

Reproduction

The males build nests containing watery plants and protègents the eggs, then the alevins. The latter have a size of approximately 10 cm after the blossoming.

Physiology

Although it has gills, it must go back periodically to surface for gober of the air and it is in its richly vascularized mouth that are made the gaseous exchange. These characteristics enable him to carry out ways on the dry land and to be satisfied with water low in oxygen.

It hardly has the predatory ones and is not great interest for the populations, the electric shocks being able to occur up to 8 a.m. after its death.

It is the only species of the kind Electrophorus . Although same family that the gymnote, the electric eel is another kind. Certain authors classify the electric one in a family with share, the electrophoridae.

Historical descriptions

Alexander von Humboldt made a seizing description of its meeting with of Gymnotes during its famous forwarding in South America, at the beginning of the XIXe century:

" The fear of the electric eel discharges if is exaggerated in the population which we could obtain none in three days. Our guide took along horses and mules and inserted them in water. In five minutes approximately two horses drowned. The eel of one meter sixty length rubbed with the belly of the horse and a shock gave him. But slowly the violence of the unequal combat was calmed and the exhausted eels dispersed. In one nothing time we had five large eels. After studyhaving studied them during four hours, we had until the shortly of cramps, the pains to the articulations and a nausea générale." (translation since the German article wikipedia " Zitteraal")

Seek

The Museum Aquarium of Nancy currently undertakes a research on the use of gymnotes to examine water quality. Indeed, the frequency of the electric impulses emitted by a healthy gymnote in clean medium is of an astonishing regularity. However, as soon as water is polluted, by oil residues for example, the signal is disturbed.

External bonds

Discovered Neuro-transmitters in electric fish: http://www.apteronote.com/revue/histoire/article_21.shtml

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