View source for Thunnus

{{Short description|Genus of fishes}}
{{About|the genus|the subgenus|Thunnus (subgenus)}}
{{Main|Tuna}}
{{Automatic taxobox
| name = True tunas
| fossil_range = {{Fossilrange|Tertiary|holocene}}<ref name=Graham2004/><ref>{{cite journal
 |last=Sepkoski 
 |first=Jack 
 |title=A compendium of fossil marine animal genera 
 |journal=Bulletins of American Paleontology 
 |volume=364 
 |page=560 
 |year=2002 
 |url=http://strata.ummp.lsa.umich.edu/jack/showgenera.php?taxon=611&rank=class 
 |accessdate=2008-01-08 
 |url-status=dead 
 |archive-url=https://web.archive.org/web/20110723131237/http://strata.ummp.lsa.umich.edu/jack/showgenera.php?taxon=611&rank=class 
 |archive-date=2011-07-23 
}}</ref>
| image = Yellowfin tuna nurp.jpg
| image_caption = [[Yellowfin tuna]]
| taxon = Thunnus
| authority = [[John Flint South|South]], 1845
| type_species = ''Scomber thynnus''
| type_species_authority = [[Carl Linnaeus|Linnaeus]], 1758
| subdivision_ranks = Subgenus
| subdivision = * ''T. ([[Thunnus (subgenus)|Thunnus]])'' (bluefin group)
* ''T. ([[Neothunnus (subgenus)|Neothunnus]])'' (yellowfin group)
| synonyms = *''Albacora'' <small>[[David Starr Jordan|Jordan]], 1888</small>
*''Germo'' <small>Jordan, 1888</small>
*''Thynnus'' <small>Aguilera, 2020</small>
*''Kishinoella'' <small>Jordan & [[Carl Leavitt Hubbs|Hubbs]], 1925</small>
*''Neothunnus'' <small>Kishinouye, 1923</small>
*''Orcynus'' <small>[[Georges Cuvier|Cuvier]], 1816</small>
*''Parathunnus'' <small>[[Kishinouye]], 1923</small>
*''Semathunnus'' <small>[[Henry Weed Fowler|Fowler]], 1933</small>
}}

'''''Thunnus''''' is a [[genus]] of ocean-dwelling, [[ray-finned]] [[bony fish]] from the mackerel family, [[Scombridae]]. More specifically, ''Thunnus'' is one of five [[genus|genera]] which make up the [[tribe (biology)|tribe]] [[Thunnini]] – a tribe that is collectively known as the [[tuna]]s. Also called the '''true tunas''' or '''real tunas''', ''Thunnus'' consists of eight [[species]] of tuna (more than half of the overall tribe), divided into two [[subgenera]].

Their coloring, metallic blue on top and shimmering silver-white on the bottom, helps camouflage them from above and below. [[Atlantic bluefin tuna]], the largest member of this genus, can grow to {{convert|15|ft}} long and weigh up to {{convert|1500|lb}}.  All tunas are extremely strong, muscular swimmers, and the [[yellowfin tuna]] is known to reach speeds of up to {{convert|50|mph}} when pursuing prey.  As with all tunas, members of this genus are [[warm-blooded]], which is a rare trait among fish; this enables them to tolerate cold waters and to dive to deeper depths.<ref>{{Cite journal|last1=Bernal|first1=Diego|last2=Brill|first2=Richard W.|last3=Dickson|first3=Kathryn A.|last4=Shiels|first4=Holly A.|date=2017-12-01|title=Sharing the water column: physiological mechanisms underlying species-specific habitat use in tunas|journal=Reviews in Fish Biology and Fisheries|language=en|volume=27|issue=4|pages=843–880|doi=10.1007/s11160-017-9497-7|s2cid=20554689|issn=1573-5184|url=https://www.research.manchester.ac.uk/portal/en/publications/sharing-the-water-column-physiological-mechanisms-underlying-speciesspecific-habitat-use-in-tunas(ad10e79b-2fb8-4bb2-bc86-96eb245d23b9).html|access-date=2019-12-01|archive-date=2020-06-17|archive-url=https://web.archive.org/web/20200617191618/https://www.research.manchester.ac.uk/portal/en/publications/sharing-the-water-column-physiological-mechanisms-underlying-speciesspecific-habitat-use-in-tunas(ad10e79b-2fb8-4bb2-bc86-96eb245d23b9).html|url-status=live}}</ref> Bluefin tunas, for example, are found in [[Newfoundland]] and [[Iceland]], and also in the tropical waters of the [[Gulf of Mexico]] and the [[Mediterranean Sea]], where some individuals go each year to spawn.

Due to [[overfishing]], the range of this genus has declined significantly, having been effectively extirpated from the [[Black Sea]], for example.<ref>Hogan, C. Michael, [http://www.eoearth.org/wiki/Overfishing ''Overfishing''. Encyclopedia of Earth. eds. Sidney Draggan and Cutler Cleveland]. National council for Science and the Environment, Washington DC</ref>

==Taxonomy==
The word {{lang|la|Thunnus}} is the [[Middle Latin]] form of the Greek {{Transliteration|grc|thýnnos}} ({{wikt-lang|grc|θύννος}}, "tuna, {{linktext|tunny}}") – which is in turn derived from {{Transliteration|grc|thynō}} ({{lang|grc|θύνω}}, "to rush; to dart").<ref>{{LSJ|qu/nnos|θύννος|longref}}</ref><ref>{{LSJ|qu/nw|θύνω|shortref}}.</ref>  The first written use of the word was by [[Homer]].{{Citation needed|date=April 2010}}

Based on morphology and short-length [[mitochondrial DNA]] sequence data,<ref name="Alvarado Bremer 1997">{{cite journal |doi=10.1111/j.1095-8649.1997.tb01948.x |title=ROrthodox and unorthodox phylogenetic relationships among tunas revealed by the nucleotide sequence analysis of the mitochondrial DNA control region |journal=Journal of Fish Biology |volume=50 |issue= 3|pages=540–554|year=2016 |last1=Alvarado Bremer |first1=J.R. |last2=Naseri |first2=I. |last3=Ely |first3=B. }}</ref> the genus ''Thunnus'' is currently classified into two [[subgenera]]: ''Thunnus (Thunnus)'' (the bluefin group), and ''Thunnus (Neothunnus)'' (the yellowfin group). However this classification has been questioned by a recent phylogenetic analysis of nuclear DNA sequence data, which resolved different relationships among species and did not support the traditional definition of the bluefin and yellowfin groups.<ref name="Diaz-Arce 2016">{{cite journal |doi=10.1016/j.ympev.2016.06.002 |pmid= 27286653|title=RAD-seq derived genome-wide nuclear markers resolve the phylogeny of tunas |journal=Molecular Phylogenetics and Evolution|volume=102 |pages=202–207|year=2016 |last1=Díaz-Arce |first1=Natalia |last2=Arrizabalaga |first2=Haritz |last3=Murua |first3=Hilario |last4=Irigoien |first4=Xabier |last5=Rodríguez-Ezpelata  |first5=Naiara |hdl= 10754/612968|hdl-access=free }}</ref><ref>{{Cite journal|last1=Ciezarek|first1=Adam G.|last2=Osborne|first2=Owen G.|last3=Shipley|first3=Oliver N.|last4=Brooks|first4=Edward J.|last5=Tracey|first5=Sean R.|last6=McAllister|first6=Jaime D.|last7=Gardner|first7=Luke D.|last8=Sternberg|first8=Michael J. E.|last9=Block|first9=Barbara|last10=Savolainen|first10=Vincent|date=2019-01-01|title=Phylotranscriptomic Insights into the Diversification of Endothermic Thunnus Tunas|journal=Molecular Biology and Evolution|language=en|volume=36|issue=1|pages=84–96|doi=10.1093/molbev/msy198|issn=0737-4038|pmc=6340463|pmid=30364966}}</ref> Specifically, these analyses substantiated the division of Pacific and Atlantic Tuna in two separate species and suggested that Bigeye Tuna were actually a member of subgenus ''Neothunnus'', not subgenus ''Thunnus''.<ref name="Diaz-Arce 2016" /> Earlier nuclear [[ribosomal DNA]] phylogenetic reconstructions also showed similar results.<ref name="Chow 2006">{{cite journal |doi=10.1111/j.0022-1112.2006.00945.x |title=Phylogenetic relationships among ''Thunnus'' species inferred from rDNA ITS1 sequence |journal=Journal of Fish Biology |volume=68 |issue= A|pages=24–35|year=2006 |last1=Chow |first1=S. |last2=Nakagawa |first2=T. |last3=Suzuki |first3=N. |last4=Takeyama |first4=H. |last5=Matsunaga  |first5=T. }}</ref>

[[File:Thunnus spec 01.jpg|thumb|Fossil specimen]]
This genus has eight species in two [[subgenera]]:
* Subgenus ''Thunnus ([[Thunnus (subgenus)|Thunnus]])'':
**[[Albacore]], ''T. alalunga'' <small>([[Pierre Joseph Bonnaterre|Bonnaterre]], 1788)</small>
** [[Southern bluefin tuna]], ''T. maccoyii'' <small>([[François Louis Nompar de Caumat de Laporte Castelnau|Castelnau]], 1872)</small>
** [[Bigeye tuna]], ''T. obesus'' <small>(Lowe, 1839)</small>
** [[Pacific bluefin tuna]], ''T. orientalis'' <small>([[Coenraad Jacob Temminck|Temminck]] & [[Hermann Schlegel|Schlegel]], 1844)</small>
** [[Atlantic bluefin tuna]], ''T. thynnus'' <small>([[Carl Linnaeus|Linnaeus]], [[10th edition of Systema Naturae|1758]])</small>
* Subgenus ''Thunnus ([[Neothunnus (subgenus)|Neothunnus]])'':
** [[Yellowfin tuna]], ''T. albacares'' <small>([[Pierre Joseph Bonnaterre|Bonnaterre]], 1788)</small>
** [[Blackfin tuna]], ''T. atlanticus'' <small>([[René-Primevère Lesson|Lesson]], 1831)</small>
** [[Thunnus tonggol|Longtail tuna]], ''T. tonggol'' <small>([[Pieter Bleeker|Bleeker]], 1851)</small>

[[File:Tuna Relative Sizes.jpg|thumb|Relative sizes of various tunas, with the [[Atlantic bluefin tuna]] (top) at about {{convert|8|ft|m|abbr=on|1}} in this sample]]

<div class="thumb" style="margin: 5px; clear: left; width: 98%;"><div class="overflowbugx" style="overflow:auto;border=1">
{{cladogram|title=The true tunas of the genus ''Thunnus'', within the family Scombridae
 |align=center
 |caption=Cladogram: ''Thunnus'' (bottom-right in image above) is one of five genera that make up the Thunnini tribe. Known as the true tunas, it comprises 8 of the 15 extant tuna species.<ref name=Graham2004>{{cite journal
    |last=Graham|first=Jeffrey B.|author2=Dickson, Kathryn A. |title=Tuna Comparative Physiology|journal=The Journal of Experimental Biology
    |year=2004|volume=207|issue=23|pages=4015–4024|doi=10.1242/jeb.01267|pmid=15498947|doi-access=}}</ref>
 |cladogram={{clade| style=font-size:90%;line-height:90%;width:700px;
    |label1=[[Scombridae]]
    |1={{clade
       |label1=[[Gasterochismatinae]]
       |1=[[Butterfly kingfish]]es (1 genus)
       |label2=[[Scombrinae]]
       |2={{clade
          |1={{clade
             |1={{clade
               |label1=[[Scombrini]]
               |1=[[Mackerel]]s (2 genera) <span style="{{MirrorH}}">[[File:Scomber scombrus.png|50 px]]</span>
               }}
             |2={{clade
                |1={{clade
                   |label1=[[Scomberomorini]]
                   |1=[[Spanish Mackerel]]s (3 genera) <span style="{{MirrorH}}">[[File:Scomberomorus cavalla.png|50 px]]</span>
                   }}
                |2={{clade
                   |1={{clade
                      |label1=[[Sardini]]
                      |1=[[Bonito]]s (4 genera) <span style="{{MirrorH}}">[[File:Sarda sarda.jpg|50 px]]</span>
                      |label2=[[Thunnini]]
                         |sublabel2=([[Tuna]]s)
                         |2={{clade
                            |1={{black|''[[Allothunnus]]'', slender tunas}}
                            |2={{clade
                               |1={{black|''[[Auxis]]'', frigate tunas}} [[File:XRF-Auxis thazard.png|50 px]]
                               |2={{clade
                                  |1={{black|''[[Euthynnus]]'', little tunas}} [[File:XRF-Euthynnus alletteratus.png|50 px]]
                                  |2={{clade
                                     |1={{black|''[[Katsuwonus]]'', skipjack tunas}} <span style="{{MirrorH}}">[[File:Katsuwonus pelamis.png|50 px]]</span>
                                     |2={{clade |thickness=2
                                        |label1={{black|''Thunnus''}}
                                        |sublabel1={{black|(true tunas)}}
                                        |1={{clade |thickness=2
                                           |label1={{black|subgenus ''[[Thunnus (subgenus)|Thunnus]]''}}
                                           |1={{black|bluefin group}} <span style="{{MirrorH}}">[[File:Thunnus thynnus.png|50 px]]</span>
                                           |label2={{black|subgenus ''[[Neothunnus (subgenus)|Neothunnus]]''}}
                                           |2={{black|yellowfin group}} <span style="{{MirrorH}}">[[File:Thunnus albacares.png|50 px]]</span>
                                           }}
                                        }}
                                     }}
                                  }}
                               }}
                            }}
                         }}
                      }}
                   }}
                }}
             }}
          }}
       }}
   }}
</div></div>

{{cladogram|title=Alternative evolutionary tree for ''Thunnus''|align=center|caption=An alternative phylogenetic reconstruction for the genus ''Thunnus'', based on nuclear DNA sequence data, which modifies the traditionally recognized bluefin and yellowfin clades by placing ''Thunnus obesus'' within the yellowfin clade instead of in the bluefin clade.<ref name="Diaz-Arce 2016" />
|{{clade |style=font-size:85%; line-height:85%;
|1={{clade
 |1={{clade
  |1={{clade
   |1={{clade
    |1={{clade
     |1=''[[Thunnus albacares|T. albacares]]'' <span style="{{MirrorH}}">[[File:Thunnus albacares.png|50 px]]</span>
     |2=''[[Thunnus obesus|T. obesus]]'' <span style="{{MirrorH}}">[[File:Thunnus obesus.png|50 px]]</span>}}
    |2={{clade
     |1=''[[Thunnus tonggol|T. tonggol]]''
     |2=''[[Thunnus atlanticus|T. atlanticus]]'' <span style="{{MirrorH}}">[[File:Blackfin tuna, Duane Raver Jr.jpg|50 px]]</span>}} }}
   |2=''[[Thunnus maccoyii|T. maccoyii]]''}}
  |2={{clade
   |1=''[[Thunnus thynnus|T. thynnus]]'' <span style="{{MirrorH}}">[[File:Thunnus thynnus.png|50 px]]</span>
   |2=''[[Thunnus orientalis|T. orientalis]]''}} }}
 |2=''[[Thunnus alalunga|T. alalunga]]'' <span style="{{MirrorH}}">[[File:Thunnus alalunga.png|50 px]]</span>}}
}}
}}

{{clear left}}

==Species==
Until recently,  seven ''Thunnus'' species were thought to exist, and Atlantic bluefin tuna and Pacific bluefin tuna were [[subspecies]] of a single species.  In 1999, Collette established that based on both molecular and morphological considerations, they are, in fact, distinct species.<ref>{{cite conference |last=Collette |first=B.B. |conference=5th Indo-Pacific Fish Conference: Nouméa, New Caledonia, 3–8 November 1997 |editor=Séret, B. |editor2=Sire, J.Y. |title=Mackerels, molecules, and morphology |year=1999 |publisher=Société Française d'Ichtyologie [u.a.] |book-title=Proceedings |location=Paris |isbn=978-2-9507330-5-4 |pages=149–164 |url=https://books.google.com/books?id=-0cWAQAAIAAJ |access-date=2017-09-16 |archive-date=2023-11-30 |archive-url=https://web.archive.org/web/20231130165207/https://books.google.com/books?id=-0cWAQAAIAAJ |url-status=live }}</ref><ref name=Tanaka2006>{{cite journal|last1=Tanaka |first1=Y. |first2=K. |last2=Satoh |first3=M. |last3=Iwahashi |first4=H. |last4=Yamada |title=Growth-dependent recruitment of Pacific bluefin tuna ''Thunnus orientalis'' in the northwestern Pacific Ocean |journal=Marine Ecology Progress Series |year=2006 |volume=319 |pages=225–235 |doi=10.3354/meps319225 |bibcode=2006MEPS..319..225T |doi-access=free }}</ref>

{{Tuna table/header|''Thunnus'', the true tunas}}
{{Tuna_table/Thunnus_(Thunnus)}}
{{Tuna_table/Thunnus_(Neothunnus)}}
|}

[[File:Tuna sizes.svg|thumb|left|450px|Maximum reported sizes of ''Thunnus'' species.]]
{{clear left}}

==Overfishing==
The worldwide demand for [[sushi]] and [[sashimi]], coupled with increasing population growth, has resulted in global stocks of the species being overfished<ref>{{cite book|url=https://books.google.com/books?id=0JkKOFIj5pgC&pg=PA522|page=522|title=Introduction to Marine Biology|publisher=Cengage Learning|author1=George Karleskint |author2=Richard Turner |author3=James Small |year=2009|isbn=978-0-495-56197-2}}</ref> and bluefin is the most endangered and considered "a serious conservation concern".<ref>{{cite web|url=http://www.montereybayaquarium.org/cr/SeafoodWatch/web/sfw_factsheet.aspx?gid=69 |title=Tuna, Bluefin |url-status=dead |archive-url=https://web.archive.org/web/20110722190940/http://www.montereybayaquarium.org/cr/SeafoodWatch/web/sfw_factsheet.aspx?gid=69 |archive-date=2011-07-22 }}</ref> Complicating the efforts for sustainable management of bluefin fish stocks within national exclusive economic zones ([[Exclusive Economic Zone|EEZ]]) is bluefin migrate long distances and hunt in the midocean that is not part of any country's EEZ, so have been vulnerable to overfishing by multiple countries' fishing fleets. International agreements and conventions are good-faith agreements and are difficult to monitor or enforce.<ref name="economist">{{cite news | url=http://www.economist.com/node/12502783?story_id=12502783 | newspaper=The Economist | title=Managed to death | date=2008-10-30 | access-date=2011-01-08 | archive-date=2011-02-11 | archive-url=https://web.archive.org/web/20110211161804/http://www.economist.com/node/12502783?story_id=12502783 | url-status=live }}</ref> Though this fish has been farmed in captivity by the Japanese and by the Australians with the help of the Japanese,<ref>[[Thunnus orientalis#Farming]]</ref> yields are lower than other farmed fish due to the slow growth rate of bluefin tuna, therefore keeping prices high.<ref name="economist"/> On December 30, 2012, a {{convert|222|kg|lb|adj=on}} bluefin tuna caught off northeastern Japan, was sold at the [[Tsukiji fish market]] in [[Tokyo]] for a record 155.4 million yen ($1.76 million) &ndash; a unit price of JP¥&nbsp;1.274&nbsp;million/kg (US$3,600/lb).<ref>{{cite news|title=A bluefin tuna sells for record $1.76M in Tokyo|url=https://www.usatoday.com/story/news/world/2013/01/04/bluefin-tuna-tokyo-sushi/1810557/?dlvrit=206567|publisher=USA Today|accessdate=5 January 2013|date=4 January 2013|archive-date=28 July 2018|archive-url=https://web.archive.org/web/20180728072830/https://www.usatoday.com/story/news/world/2013/01/04/bluefin-tuna-tokyo-sushi/1810557/?dlvrit=206567|url-status=live}}</ref>

==References==
{{Reflist|2}}

==Further reading==
* Charles Clover. 2004. ''[[The End of the Line: How Overfishing Is Changing the World and What We Eat]]''. Ebury Press, London. {{ISBN|0-09-189780-7}}
*{{cite journal|last=Newlands|first=Nathaniel K.|author2=Molly E. Lutcavage |author3=Tony J. Pitcher |year=2006|title=Atlantic Bluefin Tuna in the Gulf of Maine, I: Estimation of Seasonal Abundance Accounting for Movement, School and School-Aggregation Behaviour|journal=Environmental Biology of Fishes|volume=77|issue=2|pages=177–195|issn=0378-1909|doi=10.1007/s10641-006-9069-5|s2cid=12596873}}

== External links ==
{{Commons category}}
* {{FishBase genus | genus = Thunnus | month = January | year = 2006}}
* [http://www.tunafacts.com/healthbenefits/index.html Nutritional benefits of tuna] {{Webarchive|url=https://web.archive.org/web/20160119175526/http://www.tunafacts.com/healthbenefits/index.html |date=2016-01-19 }}
*[http://www.iccat.int/en The International Commission for the Conservation of Atlantic Tunas]

{{tuna}}

{{Taxonbar|from=Q2346039}}
{{Authority control}}

[[Category:Thunnus| ]]
[[Category:Marine fish genera]]
[[Category:Extant Cenozoic first appearances]]