Broadhead catfish
Encyclopedia
The Broadhead Catfish or Clarias macrocephalus is an economically important air-breathing catfish
that is a native of Southeast Asia
. The fish is cultivated in fish pond
s for use in human consumption in countries such as Thailand
and the Philippines
. However, native populations now face extinction
due to man-made activities and genetic introgression due to interbreeding with escaped aquaculture
hybrids.
and its short and rounded occipital process. The occipital process is pointed in Clarias batrachus, a closely related species. Another identifying feature for the broadhead catfish is the white spots on the side of its black body. The male and the female catfish can be identified by looking at their anus. The males have an elongated urogenital papillae around their anus while the females only have a round opening. The males can reach lengths of up to 120 cm.
and fresh water
. The fish stays in tropical climates ranging in the 34°N - 4°N latitudes. As such, the fish is found in tropical Asian countries such as Thailand
, Vietnam
, China
, Malaysia, Guam
and the Philippines
. Clarias macrocephalus prefers living in marshes, canals, ricefields, stagnant pools and rivers. Should the water evaporate during the dry seasons, the fish is able to lie buried for a long time. Should there be a need to relocate, the fish can move out of the water using its extended fins.
The fish, together with other members of the genus Clarias are threatened by man-made activities such as urbanization
, habitat fragmentation, and exploitation by the expanding aquaculture business. The catfish population is also threatened by escaped hybrids born from female C. macrocephalus and male introduced
C. gariepinus
. The hybrid is able to breed with both species and could cause a Genetic introgression which could result in species extinction
. The hybrid also grows faster than the native fish and might outcompete the native stock for resources.
and smaller fishes. However, it can also eat rice bran, kitchen refuse, fish meal, or formulated feeds. . In turn, the fish is attacked by Achlya
, Aphanomyces and Pythium
. In the wild, the fish spawns in small streams. The fish does not, however, spawn on its own in captivity. Spawning must be induced by injecting mature females with hormones. The eggs from the female are removed while milt
, obtained from the reproductive tract of sacrificed males, are introduced. The resulting catfish larvae can be fed with newly hatched brine shrimp
and water fleas four to five days after hatching. After more than one month, the fingerling
s can be transferred to grow-out ponds.
both this fish and the walking catfish
(Clarias batrachus) are known as Pla Duk . They are common inexpensive food items, prepared in a variety of ways, being often offered by street vendors, especially barbecue
d or fried.
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...
that is a native of Southeast Asia
Southeast Asia
Southeast Asia, South-East Asia, South East Asia or Southeastern Asia is a subregion of Asia, consisting of the countries that are geographically south of China, east of India, west of New Guinea and north of Australia. The region lies on the intersection of geological plates, with heavy seismic...
. The fish is cultivated in fish pond
Pond
A pond is a body of standing water, either natural or man-made, that is usually smaller than a lake. A wide variety of man-made bodies of water are classified as ponds, including water gardens, water features and koi ponds; all designed for aesthetic ornamentation as landscape or architectural...
s for use in human consumption in countries such as Thailand
Thailand
Thailand , officially the Kingdom of Thailand , formerly known as Siam , is a country located at the centre of the Indochina peninsula and Southeast Asia. It is bordered to the north by Burma and Laos, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the...
and the Philippines
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
. However, native populations now face extinction
Extinction
In biology and ecology, extinction is the end of an organism or of a group of organisms , normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point...
due to man-made activities and genetic introgression due to interbreeding with escaped aquaculture
Aquaculture
Aquaculture, also known as aquafarming, is the farming of aquatic organisms such as fish, crustaceans, molluscs and aquatic plants. Aquaculture involves cultivating freshwater and saltwater populations under controlled conditions, and can be contrasted with commercial fishing, which is the...
hybrids.
Description
The broadhead catfish is identified by its large dorsal finDorsal 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...
and its short and rounded occipital process. The occipital process is pointed in Clarias batrachus, a closely related species. Another identifying feature for the broadhead catfish is the white spots on the side of its black body. The male and the female catfish can be identified by looking at their anus. The males have an elongated urogenital papillae around their anus while the females only have a round opening. The males can reach lengths of up to 120 cm.
Habitat and distribution
The Broadhead fish prefers the Benthopelagic zone and can survive in both brackishBrackish water
Brackish water is water that has more salinity than fresh water, but not as much as seawater. It may result from mixing of seawater with fresh water, as in estuaries, or it may occur in brackish fossil aquifers. The word comes from the Middle Dutch root "brak," meaning "salty"...
and fresh water
Fresh Water
Fresh Water is the debut album by Australian rock and blues singer Alison McCallum, released in 1972. Rare for an Australian artist at the time, it came in a gatefold sleeve...
. The fish stays in tropical climates ranging in the 34°N - 4°N latitudes. As such, the fish is found in tropical Asian countries such as Thailand
Thailand
Thailand , officially the Kingdom of Thailand , formerly known as Siam , is a country located at the centre of the Indochina peninsula and Southeast Asia. It is bordered to the north by Burma and Laos, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the...
, Vietnam
Vietnam
Vietnam – sometimes spelled Viet Nam , officially the Socialist Republic of Vietnam – is the easternmost country on the Indochina Peninsula in Southeast Asia. It is bordered by China to the north, Laos to the northwest, Cambodia to the southwest, and the South China Sea –...
, China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
, Malaysia, Guam
Guam
Guam is an organized, unincorporated territory of the United States located in the western Pacific Ocean. It is one of five U.S. territories with an established civilian government. Guam is listed as one of 16 Non-Self-Governing Territories by the Special Committee on Decolonization of the United...
and the Philippines
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
. Clarias macrocephalus prefers living in marshes, canals, ricefields, stagnant pools and rivers. Should the water evaporate during the dry seasons, the fish is able to lie buried for a long time. Should there be a need to relocate, the fish can move out of the water using its extended fins.
The fish, together with other members of the genus Clarias are threatened by man-made activities such as urbanization
Urbanization
Urbanization, urbanisation or urban drift is the physical growth of urban areas as a result of global change. The United Nations projected that half of the world's population would live in urban areas at the end of 2008....
, habitat fragmentation, and exploitation by the expanding aquaculture business. The catfish population is also threatened by escaped hybrids born from female C. macrocephalus and male introduced
Introduced species
An introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...
C. gariepinus
Clarias gariepinus
Clarias gariepinus or African sharptooth catfish is a species of catfish of the family Clariidae, the airbreathing catfishes.- Natural Distribution :...
. The hybrid is able to breed with both species and could cause a Genetic introgression which could result in species extinction
Extinction
In biology and ecology, extinction is the end of an organism or of a group of organisms , normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point...
. The hybrid also grows faster than the native fish and might outcompete the native stock for resources.
Ecology and life history
As a carnivore, it feeds on aquatic insects, young shrimpShrimp
Shrimp are swimming, decapod crustaceans classified in the infraorder Caridea, found widely around the world in both fresh and salt water. Adult shrimp are filter feeding benthic animals living close to the bottom. They can live in schools and can swim rapidly backwards. Shrimp are an important...
and smaller fishes. However, it can also eat rice bran, kitchen refuse, fish meal, or formulated feeds. . In turn, the fish is attacked by Achlya
Achlya
Achlya is a genus of water mould....
, Aphanomyces and Pythium
Pythium
Pythium is a genus of parasitic oomycete. Most species are plant parasites, but Pythium insidiosum is an important pathogen of animals...
. In the wild, the fish spawns in small streams. The fish does not, however, spawn on its own in captivity. Spawning must be induced by injecting mature females with hormones. The eggs from the female are removed while milt
Milt
Milt is the seminal fluid of fish, mollusks, and certain other water-dwelling animals who reproduce by spraying this fluid, which contains the sperm, onto roe .-Milt as food:...
, obtained from the reproductive tract of sacrificed males, are introduced. The resulting catfish larvae can be fed with newly hatched brine shrimp
Brine shrimp
Artemia is a genus of aquatic crustaceans known as brine shrimp. Artemia, the only genus in the family Artemiidae, has changed little externally since the Triassic period...
and water fleas four to five days after hatching. After more than one month, the fingerling
Fingerling
Fingerling can refer to:*Fingerling , a character from Dutch fiction,*Fingerling potato, a small potato*Fingerling , worn like a traditional ring but constructed from fabric, vinyl, or leather....
s can be transferred to grow-out ponds.
Importance to humans
The catfish is sold commercially as live or frozen. It is prepared by either frying, broiling or baking it. The fish is can also be packaged in cans though its black skin should be removed as it looks unattractive. The fish is cultivated but only in small scale fish ponds as it has shown slow growth rate and a small amount of fry even though it is more preferred due to its appearance and eating quality. In Thailand, the fish considered better and more nourishing than the walking catfish.As food
In ThailandThailand
Thailand , officially the Kingdom of Thailand , formerly known as Siam , is a country located at the centre of the Indochina peninsula and Southeast Asia. It is bordered to the north by Burma and Laos, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the...
both this fish and the walking catfish
Walking catfish
The walking catfish, Clarias batrachus, is a species of freshwater airbreathing catfish found primarily in Southeast Asia, so named for its ability to "walk" across dry land, to find food or suitable environments...
(Clarias batrachus) are known as Pla Duk . They are common inexpensive food items, prepared in a variety of ways, being often offered by street vendors, especially barbecue
Barbecue
Barbecue or barbeque , used chiefly in the United States, Canada, the United Kingdom, New Zealand and Australia is a method and apparatus for cooking meat, poultry and occasionally fish with the heat and hot smoke of a fire, smoking wood, or hot coals of...
d or fried.