Horabagrus
Encyclopedia
Horabagrus is a small genus
of catfish
es (order
Siluriformes). It comprises two species
, H. brachysoma and H. nigricollaris. H. brachysoma is an important food fish, and both species are available as aquarium
fish.
in 1864 under the name Pseudobagrus brachysoma. Horabagrus nigricollaris was described by Pethiyagoda and Kottelat in 1994.
The genus Horabagrus is usually classified under the family Bagridae
, but there are disagreements. The genus name is after the Indian zoologist Sunder Lal Hora
. Though listed under Bagridae, Horabagrus is not listed under either of the two Bagrid subfamilies by the All Catfish Species Inventory. In Nelson (2006), the genus is provisionally placed in the family Schilbeidae
, where it is sometimes recognized as its own subfamily. In de Pinna (1998), this genus is classified as sister to the catfishes Pangasiidae and above, which would require a separate family. This genus has also been classified in its own family "Horabagridae". In a 2007 paper, Horabagrus was not classified under any current catfish families.
. H. brachysoma is known only from the Kerala Backwaters
, Vembanad Lake
and the Uttara Kannada
district of Karnataka
. H. nigricollaris is only found in the Chalakudy River
in Kerala, India. H. brachysoma is found in smooth flowing areas with much vegetation.
with a hard spine as well as an adipose fin. There are four pairs of barbels
, one nasal, one maxillary (sides of the mouth), and two mandibular (chin). H. nigricollaris is sleeker in body shape than H. brachysoma. H. brachysoma reaches about 45 centimetres (18 in). H. nigricollaris reaches about 27 cm (11 in). These two species are quite similar in appearance. H. brachysoma hosts a large black shoulder spot on either side with light outlines. However, in H. nigricollaris the marking extends over the neck, forming a "black collar" (hence the scientific name). H. brachysoma also has a more yellowish body than H. nigricollaris.
The diet of H. brachysoma has been studied. It is an unspecialized feeder and eats a variety of meaty foods. Food items include crustacean
s, molluscs, and fish
. Adults may consume terrestrial insect
s and even frog
s. Stomachs of these fish contain detritus
which is indicative of its bottom-feeding habits. This flexible diet is beneficial in its variable habitat, in which food availality is affected by monsoon
s. Feeding rate is known to increase during the breeding season in the months following the monsoon season. Spawning occurs before the monsoons and finishes by the southwest monsoon in the summer.
trade. H. nigricollaris is more seldom seen because it is not commercially farmed like the former. Nevertheless, the care for these two species is similar. These fish are said to have a lot of "personality". These fish are adaptable and are not picky about water conditions; also, they are hardy and easy to feed. However, these fish are light-shy and require plants or decorations to hide underneath for darkness; these fish are relatively secretive during the day.
. However, H. brachysoma is considered to be an endangered species
and H. nigricollaris is considered a critically endangered species. H. brachysoma is marketed live and supports a local fishery
during the rainy season. Overexploitation
, habitat alteration
, pollution
and related anthropogenic pressures on their natural habitats have considerably reduced populations of this species by 60–70% during the last few years. Research is currently being funded to study H. brachysoma, especially its captive breeding. National Bureau of Fish Genetic Resources Cochin Unit, Kerala, India have reported the genetic variation and population structure of this species using different genetic markers. Due to the importance of H. brachysoma as a food and ornamental fish, it embodies the problems that must be resolved for sustainable management, and could be used as a flagship species
to provide focus for media attention for conservation.
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). It comprises two 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...
, H. brachysoma and H. nigricollaris. H. brachysoma is an important food fish, and both species are available as 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.
Common names
H. brachysoma is known as "Günther's catfish" or "yellow catfish". It is also known as manjakoori in its native range. It is also known by a host of other names, such as "bullseye catfish", "golden red tail catfish", "solar catfish", and "sun catfish". H. nigricollaris is known as the "Black Collared Catfish".Taxonomy
Horabagrus brachysoma was described by Albert C. L. G. GüntherAlbert C. L. G. Günther
Albert Karl Ludwig Gotthilf Günther FRS, also Albert Charles Lewis Gotthilf Günther , was a German-born British zoologist, ichthyologist, and herpetologist....
in 1864 under the name Pseudobagrus brachysoma. Horabagrus nigricollaris was described by Pethiyagoda and Kottelat in 1994.
The genus Horabagrus is usually classified under the family Bagridae
Bagridae
Bagridae are a family of catfish that originate from Africa and Asia from Japan to Borneo. These fish are commonly known as naked catfishes or bagrid catfishes.Large Bagrids are important as food fish. Some species are kept as aquarium fishes....
, but there are disagreements. The genus name is after the Indian zoologist Sunder Lal Hora
Sunder Lal Hora
Sunder Lal Hora was an Indian ichthyologist.Famous for the Satpura Hypothesis, a zoo-geographical hypothesis proposed by him that suggests that the central Indian Satpura Range of hills acted as a bridge providing for the Malayan affinity of many Indian fauna and flora in the peninsula and the...
. Though listed under Bagridae, Horabagrus is not listed under either of the two Bagrid subfamilies by the All Catfish Species Inventory. In Nelson (2006), the genus is provisionally placed in the family Schilbeidae
Schilbeidae
The schilbid catfishes are a family of catfishes native to Africa and southern Asia. These fish tend to swim in open water....
, where it is sometimes recognized as its own subfamily. In de Pinna (1998), this genus is classified as sister to the catfishes Pangasiidae and above, which would require a separate family. This genus has also been classified in its own family "Horabagridae". In a 2007 paper, Horabagrus was not classified under any current catfish families.
Distribution
These two species have a relatively restricted range. They are both restricted to IndiaIndia
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
. H. brachysoma is known only from the Kerala Backwaters
Kerala Backwaters
The Kerala backwaters are a chain of brackish lagoons and lakes lying parallel to the Arabian Sea coast of Kerala state in southern India. The network includes five large lakes linked by canals, both manmade and natural, fed by 38 rivers, and extending virtually half the length of Kerala state...
, Vembanad Lake
Vembanad Lake
Vembanad Lake is the longest lake in India, and the largest lake in the state of Kerala. It is also one of the largest lakes, in India. A lake spanning several districts in the state of Kerala, it is known by different names in different localities viz. Punnamada Lake in Kuttanad, Kochi Lake in...
and the Uttara Kannada
Uttara Kannada
Uttara Kannada also known as North Canara or North Kanara, is a district in the southern Indian state of Karnataka. It is bordered by the state of Goa and Belgaum District to the north, Dharwad District and Haveri District to the east, Shimoga District and Udupi District to the south and the...
district of Karnataka
Karnataka
Karnataka , the land of the Kannadigas, is a state in South West India. It was created on 1 November 1956, with the passing of the States Reorganisation Act and this day is annually celebrated as Karnataka Rajyotsava...
. H. nigricollaris is only found in the Chalakudy River
Chalakudy River
Chalakudy River or Chalakudy Puzha runs through Chalakudy town which is in the Thrissur District of Kerala state, south India. It is the 4th longest river in Kerala and its basin is between 10° 05’ to 10° 35’ North latitude and 76° 15’to 76° 55’ East longitude. This area is located in Thrissur,...
in Kerala, India. H. brachysoma is found in smooth flowing areas with much vegetation.
Appearance and anatomy
H. brachysoma has a large head and a wide mouth. The eyes are large and can be seen from below the fish. There is a 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...
with a hard spine as well as an adipose fin. There are four pairs of barbels
Barbel (anatomy)
A barbel on a fish is a slender, whiskerlike tactile organ near the mouth. Fish that have barbels include the catfish, the carp, the goatfish, sturgeon, the zebrafish and some species of shark...
, one nasal, one maxillary (sides of the mouth), and two mandibular (chin). H. nigricollaris is sleeker in body shape than H. brachysoma. H. brachysoma reaches about 45 centimetres (18 in). H. nigricollaris reaches about 27 cm (11 in). These two species are quite similar in appearance. H. brachysoma hosts a large black shoulder spot on either side with light outlines. However, in H. nigricollaris the marking extends over the neck, forming a "black collar" (hence the scientific name). H. brachysoma also has a more yellowish body than H. nigricollaris.
Habitat and ecology
H. brachysoma is found in smooth flowing areas with much vegetation. This species occupies lowland areas of rivers and backwaters with mud or sand substrate. It has also been recorded in deep pools and hill streams. H. nigricollaris inhabits hill streams at upper reaches of rivers.The diet of H. brachysoma has been studied. It is an unspecialized feeder and eats a variety of meaty foods. Food items include crustacean
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...
s, molluscs, and fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
. Adults may consume terrestrial insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
s and even frog
Frog
Frogs are amphibians in the order Anura , formerly referred to as Salientia . Most frogs are characterized by a short body, webbed digits , protruding eyes and the absence of a tail...
s. Stomachs of these fish contain detritus
Detritus
Detritus is a biological term used to describe dead or waste organic material.Detritus may also refer to:* Detritus , a geological term used to describe the particles of rock produced by weathering...
which is indicative of its bottom-feeding habits. This flexible diet is beneficial in its variable habitat, in which food availality is affected by monsoon
Monsoon
Monsoon is traditionally defined as a seasonal reversing wind accompanied by corresponding changes in precipitation, but is now used to describe seasonal changes in atmospheric circulation and precipitation associated with the asymmetric heating of land and sea...
s. Feeding rate is known to increase during the breeding season in the months following the monsoon season. Spawning occurs before the monsoons and finishes by the southwest monsoon in the summer.
In the aquarium
H. brachysoma is a common fish in the aquariumAquarium
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...
trade. H. nigricollaris is more seldom seen because it is not commercially farmed like the former. Nevertheless, the care for these two species is similar. These fish are said to have a lot of "personality". These fish are adaptable and are not picky about water conditions; also, they are hardy and easy to feed. However, these fish are light-shy and require plants or decorations to hide underneath for darkness; these fish are relatively secretive during the day.
Conservation
Neither species is listed on the IUCN Red ListIUCN Red List
The IUCN Red List of Threatened Species , founded in 1963, is the world's most comprehensive inventory of the global conservation status of biological species. The International Union for Conservation of Nature is the world's main authority on the conservation status of species...
. However, H. brachysoma is considered to be an endangered species
Endangered species
An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...
and H. nigricollaris is considered a critically endangered species. H. brachysoma is marketed live and supports a local fishery
Fishery
Generally, a fishery is an entity engaged in raising or harvesting fish which is determined by some authority to be a fishery. According to the FAO, a fishery is typically defined in terms of the "people involved, species or type of fish, area of water or seabed, method of fishing, class of boats,...
during the rainy season. Overexploitation
Overfishing
Overfishing occurs when fishing activities reduce fish stocks below an acceptable level. This can occur in any body of water from a pond to the oceans....
, habitat alteration
Habitat destruction
Habitat destruction is the process in which natural habitat is rendered functionally unable to support the species present. In this process, the organisms that previously used the site are displaced or destroyed, reducing biodiversity. Habitat destruction by human activity mainly for the purpose of...
, pollution
Pollution
Pollution is the introduction of contaminants into a natural environment that causes instability, disorder, harm or discomfort to the ecosystem i.e. physical systems or living organisms. Pollution can take the form of chemical substances or energy, such as noise, heat or light...
and related anthropogenic pressures on their natural habitats have considerably reduced populations of this species by 60–70% during the last few years. Research is currently being funded to study H. brachysoma, especially its captive breeding. National Bureau of Fish Genetic Resources Cochin Unit, Kerala, India have reported the genetic variation and population structure of this species using different genetic markers. Due to the importance of H. brachysoma as a food and ornamental fish, it embodies the problems that must be resolved for sustainable management, and could be used as a flagship species
Flagship species
The concept of flagship species is a surrogate species concept with its genesis in the field of conservation biology. The flagship species concept holds that by raising the profile of a particular species, it can successfully leverage more support for biodiversity conservation at large in a...
to provide focus for media attention for conservation.