Malapterurus
Encyclopedia
Malapterurus is a genus
of catfish
es (order
Siluriformes) of the electric catfish
family
(Malapteruridae). It includes sixteen species
.
and the Nile River. They occur in all major freshwater systems including the Buzi
, Niger
, Ogooué
, Omo
, Sanaga
, Sabi-Lundi, Senegal
, Shari, Congo
, and Zambezi River basins, as well as Lakes Albert, Chad, Kainji, Tanganyika
, and Turkana
.
. The eyes are small, the lips are rather thick, and the snout is rounded with widely separated nostrils. The gill
openings are narrow and restricted to the sides. Malapterurus species have three pairs of barbels, and lack a dorsal fin
. The pectoral, pelvic, and caudal fins are rounded. The swimbladder
has two elongate posterior chambers.
Species in Malapterurus are generally grayish-brown on the back and sides, fading to an off white or cream color on the ventral surfaces of the head and body. There are irregular black spots or blotches randomly distributed on the sides of the body. The posterior half of the caudal peduncle usually has a dark brown or black vertical bar and a cream vertical bar immediately before it. The edges of the anal and caudal fins have a cream margin, and the base of the caudal fin has a cream region and a dark brown crescent-shaped band immediately after it.
The electrogenic organ is derived from anterior body musculature and lines the body cavity. A fish that is 50 centimetre
s (19 in
) in length can discharge up to 350 V
.
It is one of the few electic species that 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 a M. Electricus to discharge on a light signal for a reward of live worms delivered automatically. This is a first in Conditioning that modified neither glandular nor muscular responses.
M. electricus can grow as large as 122 centimetre
s (48 in
) TL
and 20 kilogram
s (44 lb
).
M. electricus is a voracious piscivore
. It uses its electrical discharges to stun prey. It is an opportunistic feeder and will feed on any readily available prey in the habitat. These fish are slow-moving, deliberate feeders with infrequent, heavy meals.
Breeding pairs of M. electricus nest in holes about 3 metre
s (10 ft) in length excavated in clay banks in water 1–3 m (3–10 ft) deep.
M. electricus is eaten as food in certain parts of Africa. Along the shores of Lake Kainji, smoked electric catfish is a popular delicacy. M. electricus is also sometimes encountered as an aquarium
fish.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of catfish
Catfish
Catfishes are a diverse group of ray-finned fish. Named for their prominent barbels, which resemble a cat's whiskers, catfish range in size and behavior from the heaviest and longest, the Mekong giant catfish from Southeast Asia and the second longest, the wels catfish of Eurasia, to detritivores...
es (order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...
Siluriformes) of the electric catfish
Electric catfish
Electric catfish is the common name for the catfish family Malapteruridae. This family includes two genera, Malapterurus and Paradoxoglanis with 19 species. Several species of this family have the ability to produce an electric shock of up to 350 volts using electroplaques of an electric organ...
family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
(Malapteruridae). It includes sixteen species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
.
Distribution
The genus Malapterurus is found throughout western and central tropical AfricaAfrica
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
and the Nile River. They occur in all major freshwater systems including the Buzi
Buzi River
Buzi River is a river in Mozambique. Buzi flows eastward through the Manica and Sofala provinces of Mozambique. It then empties to the Mozambique Channel west of Beira, forming an estuary.The Buzi River is long, with a drainage basin in size...
, Niger
Niger River
The Niger River is the principal river of western Africa, extending about . Its drainage basin is in area. Its source is in the Guinea Highlands in southeastern Guinea...
, Ogooué
Ogooué River
The Ogooué , some 1,200 km long, is the principal river of Gabon in west central Africa. Its watershed drains nearly the entire country of Gabon, with some tributaries reaching into the Republic of the Congo, Cameroon, and Equatorial Guinea....
, Omo
Omo River
The Omo River is an important river of southern Ethiopia. Its course is entirely contained within the boundaries of Ethiopia, and empties into Lake Turkana on the border with Kenya...
, Sanaga
Sanaga River
The Sanaga River is a river of South Province, Cameroon, Centre Province, Cameroon, and West Province, Cameroon. Its length is 890 kilometers.The Sanaga River forms a boundary between two tropical moist forest ecoregions...
, Sabi-Lundi, Senegal
Sénégal River
The Sénégal River is a long river in West Africa that forms the border between Senegal and Mauritania.The Sénégal's headwaters are the Semefé and Bafing rivers which both originate in Guinea; they form a small part of the Guinean-Malian border before coming together at Bafoulabé in Mali...
, Shari, Congo
Congo River
The Congo River is a river in Africa, and is the deepest river in the world, with measured depths in excess of . It is the second largest river in the world by volume of water discharged, though it has only one-fifth the volume of the world's largest river, the Amazon...
, and Zambezi River basins, as well as Lakes Albert, Chad, Kainji, Tanganyika
Lake Tanganyika
Lake Tanganyika is an African Great Lake. It is estimated to be the second largest freshwater lake in the world by volume, and the second deepest, after Lake Baikal in Siberia; it is also the world's longest freshwater lake...
, and Turkana
Lake Turkana
Lake Turkana , formerly known as Lake Rudolf, is a lake in the Great Rift Valley in Kenya, with its far northern end crossing into Ethiopia. It is the world's largest permanent desert lake and the world's largest alkaline lake...
.
Description
Malapterurus have an elongate and cylindrical body that gives them the general appearance of a sausageSausage
A sausage is a food usually made from ground meat , mixed with salt, herbs, and other spices, although vegetarian sausages are available. The word sausage is derived from Old French saussiche, from the Latin word salsus, meaning salted.Typically, a sausage is formed in a casing traditionally made...
. The eyes are small, the lips are rather thick, and the snout is rounded with widely separated nostrils. The gill
Gill
A gill is a respiratory organ found in many aquatic organisms that extracts dissolved oxygen from water, afterward excreting carbon dioxide. The gills of some species such as hermit crabs have adapted to allow respiration on land provided they are kept moist...
openings are narrow and restricted to the sides. Malapterurus species have three pairs of barbels, and lack a dorsal fin
Dorsal fin
A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...
. The pectoral, pelvic, and caudal fins are rounded. The swimbladder
Gas bladder
The swim bladder, gas bladder, fish maw or air bladder is an internal gas-filled organ that contributes to the ability of a fish to control its buoyancy, and thus to stay at the current water depth without having to waste energy in swimming...
has two elongate posterior chambers.
Species in Malapterurus are generally grayish-brown on the back and sides, fading to an off white or cream color on the ventral surfaces of the head and body. There are irregular black spots or blotches randomly distributed on the sides of the body. The posterior half of the caudal peduncle usually has a dark brown or black vertical bar and a cream vertical bar immediately before it. The edges of the anal and caudal fins have a cream margin, and the base of the caudal fin has a cream region and a dark brown crescent-shaped band immediately after it.
The electrogenic organ is derived from anterior body musculature and lines the body cavity. A fish that is 50 centimetre
Centimetre
A centimetre is a unit of length in the metric system, equal to one hundredth of a metre, which is the SI base unit of length. Centi is the SI prefix for a factor of . Hence a centimetre can be written as or — meaning or respectively...
s (19 in
Inch
An inch is the name of a unit of length in a number of different systems, including Imperial units, and United States customary units. There are 36 inches in a yard and 12 inches in a foot...
) in length can discharge up to 350 V
Volt
The volt is the SI derived unit for electric potential, electric potential difference, and electromotive force. The volt is named in honor of the Italian physicist Alessandro Volta , who invented the voltaic pile, possibly the first chemical battery.- Definition :A single volt is defined as the...
.
It is one of the few electic species that 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 a M. Electricus to discharge on a light signal for a reward of live worms delivered automatically. This is a first in Conditioning that modified neither glandular nor muscular responses.
M. electricus can grow as large as 122 centimetre
Centimetre
A centimetre is a unit of length in the metric system, equal to one hundredth of a metre, which is the SI base unit of length. Centi is the SI prefix for a factor of . Hence a centimetre can be written as or — meaning or respectively...
s (48 in
Inch
An inch is the name of a unit of length in a number of different systems, including Imperial units, and United States customary units. There are 36 inches in a yard and 12 inches in a foot...
) TL
Fish measurement
Fish measurement refers to the measuring of the length of individual fish and of various parts of their anatomy. These data are used in many areas of ichthyology, including taxonomy and fisheries biology.-Overall length:...
and 20 kilogram
Kilogram
The kilogram or kilogramme , also known as the kilo, is the base unit of mass in the International System of Units and is defined as being equal to the mass of the International Prototype Kilogram , which is almost exactly equal to the mass of one liter of water...
s (44 lb
Pound (mass)
The pound or pound-mass is a unit of mass used in the Imperial, United States customary and other systems of measurement...
).
Ecology
Malapterurus species are generally found among rocks or roots in turbid or black waters with low visibility. They favor sluggish or standing water.M. electricus is a voracious piscivore
Piscivore
A piscivore is a carnivorous animal which eats primarily fish. Piscivory was the diet of early tetrapods , insectivory came next, then in time reptiles added herbivory....
. It uses its electrical discharges to stun prey. It is an opportunistic feeder and will feed on any readily available prey in the habitat. These fish are slow-moving, deliberate feeders with infrequent, heavy meals.
Breeding pairs of M. electricus nest in holes about 3 metre
Metre
The metre , symbol m, is the base unit of length in the International System of Units . Originally intended to be one ten-millionth of the distance from the Earth's equator to the North Pole , its definition has been periodically refined to reflect growing knowledge of metrology...
s (10 ft) in length excavated in clay banks in water 1–3 m (3–10 ft) deep.
Relationship to humans
The electrical discharge of M. electricus is not known to be fatal to humans.M. electricus is eaten as food in certain parts of Africa. Along the shores of Lake Kainji, smoked electric catfish is a popular delicacy. M. electricus is also sometimes encountered as an aquarium
Aquarium
An aquarium is a vivarium consisting of at least one transparent side in which water-dwelling plants or animals are kept. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, marine mammals, turtles, and aquatic plants...
fish.
Species
- Malapterurus barbatusMalapterurus barbatusMalapterurus arbatus is a species of catfish of the family Malapteruridae....
Norris, 2002 - Malapterurus beninensisMalapterurus beninensisMalapterurus beninensis is a species of catfish of the family Malapteruridae....
Murray, 1855 - Malapterurus cavalliensisMalapterurus cavalliensisMalapterurus cavalliensis is a species of catfish of the family Malapteruridae....
Roberts, 2000 - Malapterurus electricus (Gmelin, 1789)
- Malapterurus leonensisMalapterurus leonensisMalapterurus leonensis is a species of catfish of the family Malapteruridae....
Roberts, 2000 - Malapterurus melanochirMalapterurus melanochirMalapterurus melanochir is a species of catfish of the family Malapteruridae known as the "electric catfish" and is found in Africa in the middle and upper Congo River basin, Democratic Republic of the Congo....
Norris, 2002 - Malapterurus microstomusMalapterurus microstomusMalapterurus microstomus is a species of catfish of the family Malapteruridae....
Poll & Gosse, 1969 - Malapterurus minjiriya Sagua, 1987
- Malapterurus monsembeensisMalapterurus monsembeensisMalapterurus monsembeensis is a species of catfish of the family Malapteruridae....
Roberts, 2000 - Malapterurus murrayiMalapterurus murrayiMalapterurus murrayi is a species of catfish of the family Malapteruridae....
Norris, 2002 - Malapterurus occidentalisMalapterurus occidentalisMalapterurus occidentalis is a species of catfish of the family Malapteruridae....
Norris, 2002 - Malapterurus oguensisMalapterurus oguensisMalapterurus oguensis is a species of catfish of the family Malapteruridae....
Sauvage, 1879 - Malapterurus polliMalapterurus polliMalapterurus polli is a species of catfish of the family Malapteruridae....
Norris, 2002 - Malapterurus punctatusMalapterurus punctatusMalapterurus punctatus is a species of catfish of the family Malapteruridae....
Norris, 2002 - Malapterurus shirensisMalapterurus shirensisMalapterurus shirensis is a species of catfish of the family Malapteruridae....
Roberts, 2000 - Malapterurus stiassnyaeMalapterurus stiassnyaeMalapterurus stiassnyae is a species of catfish of the family Malapteruridae....
Norris, 2002 - Malapterurus tanganyikaensisMalapterurus tanganyikaensisMalapterurus tanganyikaensis is a species of catfish of the family Malapteruridae....
Roberts, 2000 - Malapterurus tanoensisMalapterurus tanoensisMalapterurus tanoensis is a species of catfish of the family Malapteruridae....
Roberts, 2000 - Malapterurus teugelsiMalapterurus teugelsiMalapterurus teugelsi is a species of catfish of the family Malapteruridae....
Norris, 2002