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Electric fish

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Title: Electric fish  
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Subject: Neuroethology, Electrocommunication, Carlos Chagas Filho, Walter Heiligenberg, Theodore Holmes Bullock
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Electric fish

Electric eels are fish capable of generating an electrical field.
Audio recording of resting electric organ discharge of Brachyhypopomus bennetti.

An electric fish is any fish that can generate electric fields. A fish that can generate electric fields is said to be electrogenic while a fish that has the ability to detect electric fields is said to be electroreceptive. Most electrogenic fish are also electroreceptive.[1] Electric fish species can be found both in the ocean and in freshwater rivers of South America (Gymnotiformes) and Africa (Mormyridae). Many fish such as sharks, rays and catfishes can detect electric fields and are thus electroreceptive, but they are not classified as electric fish because they cannot generate electricity. Most common bony fish (teleosts), including most fish kept in aquaria or caught for food, are neither electrogenic nor electroreceptive.

Video of a complete electric organ discharge. The electric field potential is represented on a sagittal across the modelled fish. Hot tones represent positive potential values, while cold tones represent negative electric potentials. The black line indicates the points where the potentials are zero.

Electric fish produce their electrical fields from a specialized structure called an

  1. ^ Alves-Gomes, J (2001). "The evolution of electroreception and bioelectrogenesis in teleost fish: a phylogenietic perspective". Journal of Fish Biology 58 (6): 1489–1511.  
  2. ^ Albert, J. S.; Crampton, W. G. R. Electroreception and electrogenesis. pp. 431–472.  In: Evans, David H.; Claiborne, James B., eds. (2006). The Physiology of Fishes (3rd ed.). CRC Press.  
  3. ^ Nelson, Mark. "What IS an electric fish?". Retrieved 10 August 2014. 
  4. ^ Kramer, Bernd (2008). "Electric Organ Discharge". In Marc D. Binder, Nobutaka Hirokawa, Uwe Windhorst (eds.). Encyclopedia of Neuroscience. Berlin, Heidelberg: Springer. pp. 1050–1056.  
  5. ^ Von der Emde, G. (1999). "Active electrolocation of objects in weakly electric fish". Journal of experimental biology, 202 (10): 1205–1215. Full text
  6. ^ Choi, Charles. "Electric Fish Advertise Their Bodies". Retrieved 10 August 2014. 
  7. ^ a b c Heiligenberg, Walter (1991) Neural Nets in Electric Fish Cambridge: MIT Press. ISBN 978-0-262-08203-7.

References

See also

Following is a table of all known electric fish species within fresh water. There are two groups of marine fishes, the electric rays (Torpediniformes: Narcinidae and Torpedinidae) and the stargazers (Perciformes: Uranoscopidae) capable of generating strong electric pulses.

Species

[7] natural conditions to study how it determined the sign of the frequency difference. They manipulated the fish’s discharge by injecting it with Eigenmannia's Neuroethologists performed several experiments under

[7] by analyzing the perturbations in its electric field. However when the frequency of a neighboring fish’s current is very close (less than 20 Hz difference) to that of its own, the fish will avoid having their signals interfere through a behavior known as Jamming Avoidance Response. If the neighbor’s frequency is higher than the fish’s discharge frequency, the fish will lower its frequency, and vice versa. The sign of the frequency difference is determined by analyzing the "beat" pattern of the incoming interference which consists of the combination of the two fish’s discharge patterns.electrolocate in its tail. Furthermore, it has the ability to electrocytes is a weakly electric fish that can self-generate electric discharges through Eigenmannia [7] study by examining the series of neural connections that led to the behavior.neuroethology expanded it into a full Walter Heiligenberg Finally, the work of   It had been theorized as early as the 1950s that electric fish near each other might experience some type of interference or inability to segregate their own signal from those of neighbors. This issue does not arise, however, because the electric fish adjust to avoid frequency interference. In 1963, two scientists, Akira Watanabe and Kimihisa Takeda, discovered the behavior of the

Jamming avoidance response

The EOD waveform takes two general forms depending on the species. In some species the waveform is continuous and almost sinusoidal (for example the genera Apteronotus, Eigenmannia and Gymnarchus) and these are said to have a wave-type EOD. In other species, the EOD waveform consists of brief pulses separated by longer gaps (for example Gnathonemus, Gymnotus, Raja) and these are said to have a pulse-type EOD.

Weakly electric fish generate a discharge that is typically less than one volt in amplitude. These are too weak to stun prey and instead are used for navigation, object detection (electrolocation) and communication with other electric fish (electrocommunication). Two of the best-known and most-studied examples are Peters' elephantnose fish (Gnathonemus petersi) and the black ghost knifefish (Apteronotus albifrons). The males of the nocturnal Brachyhypopomus pinnicaudatus, a toothless fish native to the Amazon basin, give off big, long electric hums to attract a mate.[6]

The electroreceptors to locate nearby objects.[5]

Weakly electric fish

  • Strongly electric marine fish deliver low voltage, high current electric discharges. In salt water, a small voltage can drive a large current limited by the internal resistance of the electric organ. Hence, the electric organ consists of many electrocytes in parallel. Freshwater fish have high voltage, low current discharges.
  • In freshwater, the power is limited by the voltage needed to drive the current through the large resistance of the medium. Hence, these fish have numerous cells in series.[4]

Strongly electric fish are fish with an EOD that is powerful enough to stun prey. Typical examples are the matched:

Strongly electric fish

Contents

  • Strongly electric fish 1
  • Weakly electric fish 2
  • Jamming avoidance response 3
  • Species 4
  • See also 5
  • References 6

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