Electric catfish

Electric catfish
Malapterurus electricus
Scientific classification
Kingdom:Animalia
Phylum:Chordata
Class:Actinopterygii
Order:Siluriformes
Superfamily:Siluroidea
Family:Malapteruridae
Bleeker, 1858
Genera

Malapterurus
Paradoxoglanis

Electric catfish is the common name for the catfish (order Siluriformes) family Malapteruridae. This family includes two genera, Malapterurus and Paradoxoglanis with 21 species.[1] Several species of this family have the ability to produce an electric shock of up to 350 volts using electroplaques of an electric organ.[2] Electric catfish are found in tropical Africa and the Nile River.[3] Electric catfish are usually nocturnal and carnivorous.[2] Some species feed primarily on other fish, incapacitating their prey with electric discharges,[2] but others are generalist bottom forager, feeding on things like invertebrates, fish eggs and detritus.[4] The largest can grow to about 1.2 m (4 ft) long, but most species are far smaller.[5][6]

Description

The Malapteruridae are the only group of catfish with well-developed electrogenic organs; however, electroreceptive systems are widespread in catfishes.[7] The electrogenic organ is derived from anterior body musculature and lines the body cavity.[3] Electric catfish do not have dorsal fins or fin spines. They have three pairs of barbels (the nasal pair is absent).[3] The swim bladder has elongate posterior chambers, two chambers in Malapterurus and three in Paradoxoglanis.[3]

Malapterurus is one of the few electric genera to have been conditioned by means of reward to discharge on signal. As reported in the New York Times, April 2, 1967, a researcher, Dr. Frank J. Mandriota of City College, NY, conditioned an M. electricus to discharge on a light signal for a reward of live worms delivered automatically. This is the first conditioning that modified neither glandular nor muscular responses.

The largest can grow to about 1.2 m (4 ft) SL and 20 kg (44 lb) in weight.[2][3][5] Most Malapterurus and all Paradoxoglanis species are much smaller, reaching less than 30 cm (1 ft) long.[3][5][6]

Relationship to humans

The electric catfish of the Nile was well known to the ancient Egyptians.[8] The Egyptians reputedly used the electric shock from them when treating arthritis pain.[9] They would use only smaller fish, as a large fish may generate an electric shock from 300 to 400 volts. The Egyptians have depicted the fish in their mural paintings and elsewhere;[8] the first known depiction of an electric catfish is on a slate palette of the predynastic Egyptian ruler, Narmer, about 3100 BC.[7] It was suitably called "angry catfish" in ancient Egyptian.

An account of its electric properties was given by an Arab physician of the 12th century; then as now, the fish was known by the suggestive name of raad, abo el raash, el raad or raash, which means "thunder"[8] (literally "trembler" or "shaker").

The shock of these catfish is used to stun prey and in defense. It is not known to be fatal to humans,[2] but large electric catfish can stun an adult person.[9] In small electric catfish the generated current is far less and only feels like a tingle to humans.[9]

References

  1. ↑ Ferraris, Carl J., Jr. (2007). "Checklist of catfishes, recent and fossil (Osteichthyes: Siluriformes), and catalogue of siluriform primary types" (PDF). Zootaxa. 1418: 1–628. Retrieved 2009-06-24.
  2. 1 2 3 4 5 Ng, Heok Hee (2000). "Malapterurus electricus". Animal Diversity Web. Retrieved 2007-07-28.
  3. 1 2 3 4 5 6 Nelson, Joseph S. (2006). Fishes of the World. John Wiley & Sons, Inc. ISBN 0-471-25031-7.
  4. ↑ Moelants, T. (2010). "Malapterurus microstoma". The IUCN Red List of Threatened Species. IUCN. 2010: e.T181680A7703373. doi:10.2305/IUCN.UK.2010-3.RLTS.T181680A7703373.en. Retrieved 14 January 2018.
  5. 1 2 3 Froese, Rainer, and Daniel Pauly, eds. (2017). Species of Malapterurus in FishBase. March 2017 version.
  6. 1 2 Froese, Rainer, and Daniel Pauly, eds. (2017). Species of Paradoxoglanis in FishBase. March 2017 version.
  7. 1 2 Howes, George J. (1985). "The phylogenetic relationships of the electric catfish family Malapteruridae (Teleostei: Siluroidei)". Journal of Natural History. 19: 37–67. doi:10.1080/00222938500770031.
  8. 1 2 3 Wikisource Boulenger, George Albert (1911). "Cat-fish". In Chisholm, Hugh. Encyclopædia Britannica. 5 (11th ed.). Cambridge University Press. pp. 512–515.
  9. 1 2 3 "Malapterurus electricus". ScotsCat. 3 April 2013. Retrieved 15 March 2017.
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