View source for Barbel (zoology)

{{Short description|Whiskerlike sensory organ near the mouth of a fish}}
{{for|the fishes|Barbel (fish species)}}
[[Image:Koi head closeup.jpg|right|250px|thumb|[[Koi]] carp have two pairs of barbels, the second pair being quite small.]]
[[Image:Arowana.jpg|right|250px|thumb|This [[Asian arowana]] has large, protruding barbels]]

In [[fish anatomy]] and [[Turtle#Anatomy and physiology|turtle anatomy]], a '''barbel''' is a slender, whiskerlike sensory [[organ (anatomy)|organ]] near the [[mouth]]. Fish that have barbels include the [[catfish]], the [[carp]], the [[goatfish]], the [[hagfish]], the [[sturgeon]], the [[zebrafish]], the [[Idiacanthus atlanticus|black dragonfish]] and some species of [[shark]] such as the [[sawshark]]. Barbels house the [[taste bud]]s of such fish and are used to search for [[food]] in murky water.

The word ''barbel'' comes from [[Latin]] ''barbula'' 'little beard'.<ref>{{Cite web|title=barbel|website=[[American Heritage Dictionary]]|url=https://www.ahdictionary.com/word/search.html?q=barbel|access-date=9 April 2018}}</ref> Barbels are sometimes erroneously referred to as ''[[Barb (feather)|barbs]]'', which are found in bird [[feather]]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]]s. Also, barbels are often mandibular or mental, being located on the [[chin]].

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.<ref name=":0">{{Cite journal|last=Fox|first=Harold|date=May 1999|title=Barbels and barbel-like tentacular structures in sub-mammalian vertebrates: a review|journal=Hydrobiologia|volume=403|pages=153–193|doi=10.1023/A:1003778125517|bibcode=1999HyBio.403..153F |s2cid=45206327}}</ref> 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.<ref name=":0" /> Concentrations of taste buds vary from species to species, with [[bullhead catfish]] having 25 buds in a square millimeter of barbel skin.<ref name=":1">{{Cite book|date=2004|editor-last=von der Emde|editor-first=Gerhard|editor2-last=Mogdans|editor2-first=Joachim|editor3-last=Kapoor|editor3-first=B. G.|title=The Senses of Fish|language=en-gb|doi=10.1007/978-94-007-1060-3|isbn=978-94-010-3779-2|s2cid=36978815}}</ref>

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 [[zebrafish]] and absence or difference in expression in barbel-less members of the same families.<ref>{{Cite journal|last1=Zhou|first1=Tao|last2=Li|first2=Ning|last3=Jin|first3=Yulin|last4=Zeng|first4=Qifan|last5=Prabowo|first5=Wendy|last6=Liu|first6=Yang|last7=Tian|first7=Changxu|last8=Bao|first8=Lisui|last9=Liu|first9=Shikai|last10=Yuan|first10=Zihao|last11=Fu|first11=Qiang|date=2018-05-29|title=Chemokine C-C motif ligand 33 is a key regulator of teleost fish barbel development|journal=Proceedings of the National Academy of Sciences|language=en|volume=115|issue=22|pages=E5018–E5027|doi=10.1073/pnas.1718603115|issn=0027-8424|pmc=5984497|pmid=29760055|bibcode=2018PNAS..115E5018Z |doi-access=free}}</ref> 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.<ref name=":1" /> The abyssal zone scavengers ''[[Coryphaenoides armatus]]'' possess one small mandible barbel that they use to search the seafloor for carrion to eat.<ref>{{Cite journal|last1=Bailey|first1=David M.|last2=Wagner|first2=Hans-Joachim|last3=Jamieson|first3=Alan J.|last4=Ross|first4=Murray F.|last5=Priede|first5=Imants G.|date=January 2007|title=A taste of the deep-sea: The roles of gustatory and tactile searching behaviour in the grenadier fish Coryphaenoides armatus|journal=Deep Sea Research Part I: Oceanographic Research Papers|volume=54|issue=1|pages=99–108|doi=10.1016/j.dsr.2006.10.005|bibcode=2007DSRI...54...99B|issn=0967-0637|url=http://eprints.gla.ac.uk/4787/1/4787.pdf}}</ref>  

Freckled Goatfish, ''[[Upeneus]] tragula'', develop barbels as a response to food availability.<ref>{{Cite journal|last=McCormick|first=Mark I.|date=July 1993|title=Development and changes at settlement in the barbel structure of the reef fish, Upeneus tragula (Mullidae)|journal=Environmental Biology of Fishes|volume=37|issue=3|pages=269–282|doi=10.1007/bf00004634|bibcode=1993EnvBF..37..269M |s2cid=34037401|issn=0378-1909}}</ref> 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]] 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.<ref>{{Cite journal|last1=de Freitas Barros Neto|first1=Luciano|last2=Frigo|first2=Rafael Gomes|last3=Gavilan|first3=Simone Almeida|last4=de Moura|first4=Sérgio Adriane Bezerra|last5=Lima|first5=Sergio Maia Queiroz|date=2019-12-01|title=Barbel development associated to aquatic surface respiration in Triportheus signatus (Characiformes: Triportheidae) from the semiarid Caatinga rivers|journal=Environmental Biology of Fishes|volume=103|issue=1|pages=89–98|doi=10.1007/s10641-019-00935-x|s2cid=208496992|issn=0378-1909}}</ref> 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==
{{Reflist}}

==References==
{{Commons category}}
* 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.&nbsp;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.&nbsp;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, {{doi|10.3791/1558}}.
* 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}}

[[Category:Fish anatomy]]