fish anatomy Fish anatomy is the study of the form or morphology of fish. It can be contrasted with fish physiology, which is the study of how the component parts of fish function together in the living fish. In practice, fish anatomy and fish physiology co ...

and turtle anatomy, a barbel is a slender, whiskerlike sensory organ near the

mouth In animal anatomy, the mouth, also known as the oral cavity, or in Latin cavum oris, is the opening through which many animals take in food and issue vocal sounds. It is also the cavity lying at the upper end of the alimentary canal, bounded on ...

. Fish that have barbels include the

catfish Catfish (or catfishes; order Siluriformes or Nematognathi) 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 three largest species alive, ...

, the

carp Carp are various species of oily freshwater fish from the family Cyprinidae, a very large group of fish native to Europe and Asia. While carp is consumed in many parts of the world, they are generally considered an invasive species in parts of ...

, the

goatfish The goatfishes are perciform fish of the family Mullidae. The family is also sometimes referred to as the red mullets, which also refers more narrowly to the genus '' Mullus''. The family name and the English common name mullet derived from La ...

, the

hagfish Hagfish, of the class Myxini (also known as Hyperotreti) and order Myxiniformes , are eel-shaped, slime-producing marine fish (occasionally called slime eels). They are the only known living animals that have a skull but no vertebral column, a ...

, the

sturgeon Sturgeon is the common name for the 27 species of fish belonging to the family Acipenseridae. The earliest sturgeon fossils date to the Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretace ...

, the

zebrafish The zebrafish (''Danio rerio'') is a freshwater fish belonging to the minnow family ( Cyprinidae) of the order Cypriniformes. Native to South Asia, it is a popular aquarium fish, frequently sold under the trade name zebra danio (and thus often ...

, the black dragonfish and some species of

shark Sharks are a group of elasmobranch fish characterized by a cartilaginous skeleton, five to seven gill slits on the sides of the head, and pectoral fins that are not fused to the head. Modern sharks are classified within the clade Selachimo ...

such as the

sawshark A sawshark or saw shark is a member of a shark order (Pristiophoriformes ) bearing a unique long, saw-like rostrum (snout or bill) edged with sharp teeth, which they use to slash and disable their prey. There are eight species within the Pristi ...

. Barbels house the

taste bud Taste buds contain the taste receptor cells, which are also known as gustatory cells. The taste receptors are located around the small structures known as lingual papillae, papillae found on the upper surface of the tongue, soft palate, upper e ...

s of such fish and are used to search for

food Food is any substance consumed by an organism for nutritional support. Food is usually of plant, animal, or fungal origin, and contains essential nutrients, such as carbohydrates, fats, proteins, vitamins, or minerals. The substance is inge ...

in murky water. The word "barbel" comes from the

Middle Latin Medieval Latin was the form of Literary Latin used in Roman Catholic Church, Roman Catholic Western Europe during the Middle Ages. In this region it served as the primary written language, though local languages were also written to varying deg ...

''barbula'', for "little beard." Barbels are sometimes erroneously referred to as '' barbs'', which are found in bird

feather Feathers are epidermal growths that form a distinctive outer covering, or plumage, on both avian (bird) and some non-avian dinosaurs and other archosaurs. They are the most complex integumentary structures found in vertebrates and a premier ...

s for flight. Barbels may be located in a variety of locations on the head of a fish. "Maxillary barbels" refers to barbels on either side of the mouth. Barbels may also be nasal, extending from the

nostril A nostril (or naris , plural ''nares'' ) is either of the two orifices of the nose. They enable the entry and exit of air and other gasses through the nasal cavities. In birds and mammals, they contain branched bones or cartilages called turbi ...

s. Also, barbels are often mandibular or mental, being located on the

chin The chin is the forward pointed part of the anterior mandible (List_of_human_anatomical_regions#Regions, mental region) below the lower lip. A fully developed human skull has a chin of between 0.7 cm and 1.1 cm. Evolution The presence of a we ...

. In fish, barbels can take the form of small, fleshy protrusions or long, cylindrical shaped extensions of the head of a fish. The cylindrical barbel shapes are built on an internal support system that can be made from ossified tissue or from cartilaginous connective tissue that provides a base for blood vessels and myelinated nerves to wrap around, held together in the dermis. Muscle tissue in the central region of the barbel allows the structure limited movement that aids in prey manipulation. On the epidermis, taste buds are situated on dermal papillae, small ridges of folded skin that increase the surface area of the skin and the total number of taste buds that can be concentrated on the barbel. Concentrations of taste buds vary from species to species, with

bullhead catfish ''Ameiurus'' is a genus of catfishes in the family Ictaluridae. It contains the three common types of bullhead catfish found in waters of the United States, the black bullhead (''Ameiurus melas''), the brown bullhead (''Ameiurus nebulosus''), a ...

having 25 buds in a square millimeter of barbel skin. Barbels begin to develop during the embryonic, larval, or juvenile life stages of most of the species in which they are present. Development regulation of barbels has been linked to the C-C motif ligand 33 of the chemokine family of genes, due to its presence in barbeled catfish and

and absence or difference in expression in barbel-less members of the same families. This class of genes are signalling genes that provide migrating cells directional information during morphogenesis.

Function

In most fish species, barbels are used to aid in the acquisition of food in bodies of water that have low visibility due to low light conditions or murky waters. The taste receptors are able to detect enzymes in the water and help the fish identify if it is from a possible food source or possible sources of danger. The abyssal zone scavengers ''

Coryphaenoides armatus The abyssal grenadier, ''Coryphaenoides armatus'', is an abyssal fish of the genus ''Coryphaenoides'', found in all the world's oceans, at depths between . Its adult length is , although Fishbase gives lengths up to . The abyssal grenadier's bod ...

'' possess one small mandible barbel that they use to search the seafloor for carrion to eat. Freckled Goatfish, ''

Upeneus ''Upeneus'' is a genus of goatfishes native to the Atlantic, Indian and Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, ...

tragula'', develop barbels as a response to food availability. When starved of food for two days under laboratory conditions, ''U. tragula'' develop large barbels compared to those developed by those who were fed consistently. The large barbels help the organism capture prey and compete against other individuals. However, individuals that developed large barbels also experienced a decreased growth rate. In the species ''

Triportheus ''Triportheus'' is a genus of characiform fishes from South America, including Trinidad, ranging from the Rio de la Plata basin to the basins of the Orinoco and Magdalena. Some are migratory. The largest species is up to in standard length ...

signatus'', individuals have been found to develop barbels late in life as a response to low dissolved oxygen in pools left after flood waters recede following the rainy season. These structures are more vascularized than barbels of other fish species to help gas exchange in low oxygen conditions and direct more water flow over the gills.

Notes

References

* Adriaens, D. and Verraes, W. (1997). Ontogeny of the maxillary barbel muscles in ''Clarias gariepinus'' (Siluroidei: Clariidae), with some notes on the palatine-maxillary mechanism. Journal of Zoology (London) 241, 117–133. * Bailey, D.M. , Wagner, H.J., Jamieson, A.J., Ross, M.F. and Priede, I.G. (2007) A taste of the deep-sea: The roles of gustatory and tactile searching behaviour in the grenadier fish ''Coryphaenoides armatus''. ''Deep-Sea Research Part I: Oceanographic Research Papers'', 54(1), pp. 99–108. ( doi:10.1016/j.dsr.2006.10.005) * de Freitas Barros Neto, L., Frigo, R. G., Gavilan, S. A., de Moura, S. A. B., & Lima, S. M. Q. (2020). Barbel development associated to aquatic surface respiration in Triportheus signatus (Characiformes: Triportheidae) from the semiarid Caatinga rivers. Environmental Biology of Fishes, 103(1), 89–98. https://doi.org/10.1007/s10641-019-00935-x * Eakin, R. R., Eastman, J. T. and Vacchi, M. (2006). Sexual dimorphism and mental barbel structure in the South Georgia plunderfish ''Artedidraco mirus'' (Perciformes : Notothenioidei : Artedidraconidae). Polar Biology 30, 45–52. * Fadaee, B., Pourkazemi, M., Tavakoli, M., Joushideh, H., Khoshghalb, M. R. B., Hosseini, M. R. and Abdulhay, H. (2006). Tagging and tracking juvenile sturgeons in shallow waters of the Caspian Sea (less than 10 m depth) using CWT (Coded Wire Tags) and barbel incision. Journal of Applied Ichthyology 22, 160–165. * Fox, H. (1999). Barbels and barbel-like tentacular structures in sub-mammalian vertebrates: A review. Hydrobiologia 403, 153–193. * Grover-Johnson, N. and Farbman, A. (1976). Fine structure of taste buds in the barbel of the catfish, Ictalurus punctatus. Cell Tissue Res 169, 395–403. * Hawkins, M. B. (n.d.). The development and evolutionary origin of barbels in the channel catfish Ictalurus punctatus (Siluriformes: Ictaluridae). 48. * Joyce, E. C. and Chapman, G. B. (1978). Fine structure of the nasal barbel of the channel catfish, ''Ictalurus punctatus''. Journal of Morphology 158, 109–153. * Kapoor, B. G., Evans, H. E., & Pevzner, E. A. (1976). The Gustatory System in Fish. In Advances in Marine Biology (Vol. 13, pp. 53–108). Elsevier. https://doi.org/10.1016/S0065-2881(08)60280-1 * LeClair, E.E. and Topczewski, J. (2009). Methods for the study of the zebrafish maxillary barbel. J Vis Exp, http://www.jove.com/video/1558/methods-for-the-study-of-the-zebrafish-maxillary-barbel?id=1558, . * LeClair, E.E. and Topczewski, J. (2010). Development and regeneration of the zebrafish maxillary barbel: a novel study system for vertebrate tissue growth and repair. PLoS One 5, e8737. * McCormick, M. I. (1993). Development and changes at settlement in the barbel structure of the reef fish, Upeneus tragula (Mullidae). Environmental Biology of Fishes, 37(3), 269–282. https://doi.org/10.1007/BF0000463 * Ogawa, K., Marui, T. and Caprio, J. (1997). Bimodal (taste/tactile) fibers innervate the maxillary barbel in the channel catfish. Chem Senses 22, 477–82. * von der Emde, G., Mogdans, J., & Kapoor, B. G. (Eds.). (2004). The Senses of Fish. Springer Netherlands. https://doi.org/10.1007/978-94-007-1060-3 * Zhou, T., Li, N., Jin, Y., Zeng, Q., Prabowo, W., Liu, Y., Tian, C., Bao, L., Liu, S., Yuan, Z., Fu, Q., Gao, S., Gao, D., Dunham, R., Shubin, N. H., & Liu, Z. (2018). Chemokine C-C motif ligand 33 is a key regulator of teleost fish barbel development. Proceedings of the National Academy of Sciences, 115(22), E5018–E5027. https://doi.org/10.1073/pnas.1718603115 {{Diversity of fish Fish anatomy