View source for Bowfin

{{short description|Species of ray-finned fish}}
{{Hatnote|For the [[Balao-class submarine]], see [[USS Bowfin (SS-287)|''USS'' Bowfin]].}}
{{good article}}
{{Speciesbox
| image = Amia calva.png
| image_caption = From the [[Suwanee River]], [[Florida]]
| status = LC
| status_system = IUCN3.1
| status_ref = <ref name=iucn>{{cite iucn |author=NatureServe |year=2013 |title=''Amia calva'' |article-number=e.T201942A2730796 |doi=10.2305/IUCN.UK.2013-1.RLTS.T201942A2730796.en |access-date=11 November 2021}}</ref>
| status2 = GNR
| status2_system = TNC
| status2_ref = <ref name=NatureServe>{{cite web |title=''Amia calva'' |url=https://explorer.natureserve.org/Taxon/ELEMENT_GLOBAL.2.1281382/Amia_calva|website=NatureServe Explorer An online encyclopedia of life|version=7.1 |publisher=NatureServe |access-date=3 December 2023}}</ref>
| taxon = Amia calva
| authority = [[Linnaeus]], 1766
| range_map = Bowfin distribution in US.png
| synonyms_ref = <ref name=Froese-Pauly-2017-fb/><ref name=Deeplyfish-2017-05-Amiidae/>
| range_map_caption = Combined range of both extant ''Amia'' species
| synonyms = {{collapsible list|bullets = true|title=<small>Species</small>
| ''Amia occidentalis'' <small>DeKay 1842</small>
| ''Amia marmorata'' <small>Valenciennes 1847</small>
| ''Amia ornata'' <small>Valenciennes 1847</small>
| ''Amia viridis'' <small>Valenciennes 1847</small>
| ''Amia cinerea'' <small>Valenciennes 1847</small>
| ''Amia reticulata'' <small>Valenciennes 1847</small>
| ''Amia canina'' <small>Valenciennes 1847</small>
| ''Amia lintiginosa'' <small>Valenciennes 1847</small>
| ''Amia subcoerulea'' <small>Valenciennes 1847</small>
| ''Amia thompsonii'' <small>Duméril 1870</small>
| ''Amia piquotii'' <small>Duméril 1870</small>
| ''Amiatus calvus'' <small>(Linnaeus 1766)</small>
}}
}}

The '''ruddy bowfin''' ('''''Amia calva''''') is a [[ray-finned fish]] native to North America. Common names include '''mudfish''', '''mud pike''', '''dogfish''', '''grindle''', '''grinnel''', '''swamp trout''', and '''choupique'''. It is regarded as a [[relict species|relict]], being one of only two surviving species of the [[Halecomorphi]], a group of fish that first appeared during the [[Early Triassic]], around 250&nbsp;million years ago. The bowfin is often considered a "[[Evolution of fish|living fossil]]" because they have retained some morphological [[Cladistics#Terminology for character states|characteristics of their early ancestors]]. It is one of two species in the genus ''Amia,'' along with ''[[Amia ocellicauda]]'',<ref name="Brownstein">{{Cite journal |last1=Brownstein|first1=C.D.|last2=Kim|first2=D.|last3=Orr|first3=O.D.|last4=Hogue|first4=G.M.|last5=Tracy|first5=B.H.|last6=Pugh|first6=M.W.|last7=Singer|first7=R.|last8=Myles-McBurney|first8=C.|display-authors=etal |date=27 July 2022|article-number=20220395|title=Hidden species diversity in a living fossil vertebrate |journal=Biology Letters |volume=18 |issue=11 |doi=10.1098/rsbl.2022.0395|biorxiv=10.1101/2022.07.25.500718 |s2cid=251162051 |doi-access=free|pmc=9709656|pmid=36448369}}</ref> the eyespot bowfin. The closest living relatives of bowfins are [[gar]]s, with the two groups being united in the clade [[Holostei]].

Bowfins are [[Demersal fish|demersal]] freshwater [[piscivore]]s, commonly found throughout much of the eastern United States,<ref name=NatureServe/> and in southern [[Ontario]] and [[Quebec]]. Fossil deposits indicate [[Amiiformes]] were once widespread in both freshwater and marine environments  across North and South America, Europe, Asia, and Africa. Now, their range is limited to much of the eastern United States and adjacent southern Canada, including the [[drainage basin]]s of the [[Mississippi River]], [[Great Lakes]], and various rivers exiting in the [[East Coast of the United States|Eastern Seaboard]] or [[Gulf of Mexico]]. Their preferred habitat includes vegetated sloughs, lowland rivers and lakes, swamps, and backwater areas; they are also occasionally found in brackish water. They are stalking, ambush predators known to move into the shallows at night to prey on fish and aquatic invertebrates such as crawfish, mollusks, and aquatic insects.

Like gars, bowfin are bimodal breathers—they have the capacity to breathe both water and air. Their [[Fish gill|gills]] exchange gases in the water allowing them to breathe, but they also have a [[gas bladder]] that serves to maintain buoyancy, and also allows them to breathe air by means of a small [[pneumatic duct]] connected from the foregut to the gas bladder. They can break the surface to gulp air, which allows them to survive conditions of [[Hypoxia (environmental)|aquatic hypoxia]] that would be lethal to most other species. The bowfin is long-lived, with age up to 33 years reported.<ref name=":3">{{Cite journal |last1=Lackmann |first1=Alec R. |last2=Bielak-Lackmann |first2=Ewelina S. |last3=Butler |first3=Malcolm G. |last4=Clark |first4=Mark E. |date=2022-08-23 |title=Otoliths suggest lifespans more than 30 years for free-living Bowfin Amia calva – implications for fisheries management in the bowfishing era |journal=Journal of Fish Biology |volume=101 |issue=5 |language=en |pages=1301–1311 |doi=10.1111/jfb.15201 |pmid=36053840 |pmc=9826520 |bibcode=2022JFBio.101.1301L |issn=0022-1112}}</ref>

[[File:Bowfin In Aquarium2.ogv|thumb|thumbtime=0:15|{{center|Bowfin activity in an aquarium}}]]

==Description==
The typical length of a bowfin is {{convert|50|cm|in|abbr=on}};<ref name="FishesWI" /> females typically grow to {{convert|65|-|70|cm|in|abbr=on}}, males to {{convert|50|-|65|cm|in|abbr=on}}.<ref name=Stewart-Watkinson-2004/> They can reach {{convert|109|cm|in|abbr=on}} in length, and weigh {{convert|9.75|kg|lb|abbr=on}}.<ref name="FB">{{FishBase family|family=Amiidae|year=2009|month=January}}</ref> Young of the year typically grow to {{convert|13|-|23|cm|in|abbr=on}} by October.<ref name=Stauffer-2007-FshWV/> Females tend to grow larger than males.<ref name=Davis-2003-thesis-NSU/><ref name="FLMNH">{{cite web | url=http://www.flmnh.ufl.edu/fish/Gallery/Descript/Bowfin/Bowfin.html | title=Bowfin | publisher=Florida Museum of Natural History | work=Ichthyology at the Florida Museum of Natural History | access-date=June 11, 2014 | author=University of Florida}}</ref>
[[File:Usfws-bowfin-ryan-hagertyjpg.jpg|thumb|''Amia calva'' in the [[Wacissa River]], [[Florida]]]]
The body of the bowfin is elongated and cylindrical, with the sides and back [[Olive (color)|olive]] to brown in color, often with vertical bars and dark reticulations or another camouflaged pattern. The dorsal fin has horizontal bars, and the caudal fin has irregular vertical bars. The underside is white or cream, and the paired fins and anal fin are bright green. During larval stage, hatchlings from about {{convert|7|-|10|mm|in|abbr=on}} total length are black and tadpole-like in appearance.<ref name="WVDNR">{{cite web | url=http://www.wvdnr.gov/wildlife/magazine/archive/06summer/bowfin.pdf | title=Bowfin | publisher=West Virginia DNR | work=Wildlife Diversity Notebook | date=2006 | access-date=September 25, 2014 | author=Jeff Hansbarger}}</ref> At approximately {{convert|25|mm|in|abbr=on}} total length they have been described as looking like miniature [[placoderms]].<ref name="Berra">{{cite book | chapter-url=https://books.google.com/books?id=K-1Ygw6XwFQC&pg=PA52 | title=Freshwater Fish Distribution | publisher=University of Chicago Press | chapter=Families and Maps | date=September 15, 2008 | author=Berra, Tim | page=52| isbn=978-0-226-04443-9 }}</ref> They grow quickly, and typically leave the nest within 4 to 6 weeks after hatching.<ref name="ADW">{{cite web | url=http://animaldiversity.ummz.umich.edu/accounts/Amia_calva/ | title=Amia calva | publisher=University of Michigan | work=Animal Diversity Web | access-date=September 25, 2014}}</ref> Young males have a black [[Eyespot (mimicry)|eyespot]] on the base of the tail ([[caudal peduncle]]) that is commonly encircled by an orange-yellowish border, while the female's is black, if present at all. It is thought the purpose of the eyespot is to confuse predators, deflecting attacks away from the head of the fish to its tail, which affords the bowfin an opportunity to escape predation.<ref name=Stauffer-2007-FshWV/><ref name=Schultz-2010/><ref name="IDFW">{{cite web | url=http://www.in.gov/dnr/fishwild/files/fw-bowfin.pdf | title=Bowfin (Amia calva) | publisher=Indiana Department of Natural Resources | access-date=June 13, 2014}}</ref> The bowfin is so named for its long, undulating [[dorsal fin]] consisting of 145 to 250 rays that runs from the middle of the back to the base of the tail.

The skull of the bowfin is made of two layers of skull, the [[dermatocranium]] and the [[chondrocranium]]. The chondrocranium layer cannot be seen because it is located below the dermal bones. The bowfin skull is made up of 28 fused bones, which compose the dermatocranium. The roof of the mouth is made up of three bones, the ectopterygoid, the palantine, and the vomer. They have two sets of teeth, including one set of larger sharp teeth coming out of the [[mandible|mandibular]] and [[premaxilla]]ry bones to grasp and control the prey. The other set of teeth, located posteriorly and connected to the [[hyomandibula]]r bone, is made up of pharyngeal tooth patches, which are used for sorting out nutrients and grinding down larger pieces of food. ''<ref name=":0">{{Cite journal |last=Allis |first=Edward Phelps |title=The Morphology of the Petrosal Bone and of the Sphenoidal Region of the Skull of Amia Calva |date=1897 |url=https://www.journals.uchicago.edu/doi/10.2307/1535409 |journal=Zoological Bulletin |language=en |volume=1 |issue=1 |pages=1–26 |doi=10.2307/1535409 |jstor=1535409 |issn=0898-1051|url-access=subscription }}</ref><ref name=":1">{{Cite journal |last=Prather |first=J. M. |title=The Early Stages in the Development of the Hypophysis of Amia Calva |date=1900 |url=https://www.journals.uchicago.edu/doi/10.2307/1535750 |journal=The Biological Bulletin |language=en |volume=1 |issue=2 |pages=57–80–1 |doi=10.2307/1535750 |jstor=1535750 |issn=0006-3185}}</ref><ref name=":2">{{Cite journal |last=Allis |first=Edward Phelps |title=The Homologies of the Occipital and First Spinal Nerves of Amia and Teleosts |date=1898 |url=https://www.journals.uchicago.edu/doi/10.2307/1535454 |journal=Zoological Bulletin |language=en |volume=2 |issue=2 |pages=83–97 |doi=10.2307/1535454 |jstor=1535454 |issn=0898-1051|url-access=subscription }}</ref>  ''Another three bones make up the lower jaw: the dentary, the angular, and the surangular. The cranial surface of the skull is made up of the nasals, the antorbital, the lacrimal, the parietal, the intertemporal, the post parietal, the supratemporal, the extra scapular, the post temporal, and the opercular. The entirety of the skull is attached to the girdle through another set of bones.<ref>{{Cite book|title=Vertebrates: comparative anatomy, function, evolution|last=V.|first=Kardong, Kenneth|date=2012-01-01|publisher=McGraw-Hill|isbn=978-0-07-352423-8|oclc=732361696}}</ref>

[[File:Dorsal View of a Bowfin skull.png|thumb|Dorsal view of a bowfin skull, showing the pharyngeal tooth patches which are connected to the internal portion of the hyomandibular bone. Acquired from Pacific Lutheran University.]]

[[File:AmiaCalvaHeadLankester.jpg|thumb|Drawing of a bowfin skull showing the bony plates protecting the head]]

[[File:FMIB 47066 Amia calva; g, gular plate.jpeg|thumb|Inset, drawing of gular plate]]
Bowfin are often referred to as "[[living fossil]]s" or "[[primitive fish]]" because they retained some of the primitive characters common to their ancestors,<ref name="MurrayState">{{cite web|url=http://campus.murraystate.edu/academic/faculty/tderting/anatomyatlas/bowfinatlas2/homepage.htm|publisher=Murray State University|title=The Skeletal System of the Bowfin (Amia calva)|author1=Jared Handley  |author2=Jesse Fielder |name-list-style=amp|date=2004}}</ref> including a modified (rounded externally) [[heterocercal]] [[caudal fin]], a highly vascularized [[gas bladder]] lung, vestiges of a [[spiral valve]], and a bony gular plate.<ref name="MurrayState" /><ref name="Nelson">{{cite book|publisher=John Wiley & Sons, Inc. | title=Fish of the World | author=Nelson, Joseph S. |date=2006| isbn= 978-0-471-25031-9}}</ref> The bony gular plate is located underneath the head on the exterior of the lower jaw between the two sides of the lower jaw bone. Other distinguishing characteristics include long, sharp teeth, and two protruding tube-like nostrils.<ref name=Schultz-2010/> Unlike all of the most primitive [[actinopterygians]], the scales of bowfin differ in that they are not [[Fish scale#Ganoid scales|ganoid scales]], rather they are large, single-layered [[Fish scale#Leptoid scales|cycloid]] scales closer in similarity to more derived [[teleost]]s.<ref name="WaEDU08">{{cite web | url=http://courses.washington.edu/fish311/FISH%20311%20files/08-Primitive%20bony.pdf | title=Actinopterygians: What Are They? | publisher=University of Washington | work=Biology of Fish-Fish/Biol 311 | access-date=August 8, 2014 |url-access=registration}}</ref><ref name="HelfmanCollette2009">{{cite book|author1=Gene Helfman|author2=Bruce B. Collette|author3=Douglas E. Facey|author4=Brian W. Bowen|title=The Diversity of Fish: Biology, Evolution, and Ecology|url=https://books.google.com/books?id=FyehAR6hsUUC&pg=PA37|date=3 April 2009|publisher=John Wiley & Sons|isbn=978-1-4443-1190-7|page=37}}</ref>
[[File:Bowfin.png|thumb|Lateral view of a bowfin skull: The dermal bones that are seen are composed of dermatocranium and cover the chondrocranium which is present but is located underneath the layer of dermatocranium. This specimen came from the Pacific Lutheran University Natural History collection.]]

===Fish similar in appearance===
[[Northern snakehead]]s (''Channa argus'') are commonly mistaken for bowfin because of similarities in appearance, most noticeably their elongated, cylindrical shape, and long dorsal fin that runs along their backs. Northern snakeheads are [[piscivores|piscivorous]] fish native to the rivers and estuaries of China, Russia, and Korea that have been introduced and become established in parts of North America.<ref name=NYDEC>{{cite web|url=http://www.dec.ny.gov/animals/45470.html | publisher=New York Department of Environmental Conservation | title=Northern Snakehead Fish | access-date=July 22, 2014}}</ref><ref name=nascargus>{{cite web|url=https://nas.er.usgs.gov/queries/factsheet.aspx?speciesid=2265|last1=Fuller|first1=P.L|last2=Benson|first2=A.J.|last3=Nunez|first3=G.|last4=Fusaro|first4=A.|last5=Neilson|first5=M.|title=''Channa argus'' (Cantor, 1842)|website=Nonindigenous Aquatic Species Database|publisher=U.S. Geological Survey|location=Gainesville, Florida|date=31 December 2019|orig-date=Peer reviewed on 22 September 2015|access-date=24 March 2024}}</ref>  However, unlike bowfin which are native to North America, the northern snakehead is considered an [[invasive species]] and environmentally harmful there.<ref name="TxPWD">{{cite web | url=http://www.tpwd.state.tx.us/huntwild/wild/species/exotic/snakehead_bowfin.phtml | title=Bowfin and Snakeheads: Distinguishing Features | publisher=Texas Parks & Wildlife Department | work=Brochure | access-date=August 4, 2014}}</ref><ref name="Huffington">{{cite news | url=http://www.huffingtonpost.com/2013/05/30/northern-snakehead-fish-invasive-species_n_3358192.html | title=Northern Snakehead Fish, Invasive Species, May Not Be As Bad As Originally Thought | publisher=Reuters | work=Huffington Post Green | date=May 30, 2013 | access-date=August 4, 2014 | author=Deborah Zabarenko}}</ref> Some contrasting differences in bowfin include a black [[Eyespot (mimicry)|eyespot]] on their caudal peduncle, a tan and olive coloration, a shorter anal fin, a more rounded head,<ref name="InDNR">{{cite web | url=http://www.in.gov/activecalendar/EventList.aspx?fromdate=6/1/2012&todate=6/30/2012&display=Month&type=public&eventidn=57006&view=EventDetails&information_id=114486 | title=Bowfin mistaken as snakeheads | publisher=Indiana Department of Natural Resources | work=Alerts and Notifications, event calendar press release | date=June 27, 2012 | access-date=June 14, 2014 | author=DNR}}</ref> pelvic fins at a greater distance from the pectoral fins than in the northern snakehead and the presence of the gular plate on the ventral side of the lower jaw.<ref name=nascargus/><ref>{{cite web|url=https://www.invadingspecies.com/invaders/fish/northern-snakehead-2/|title=Northern Snakehead|website=Ontario's Invading Species Awareness Program|publisher=Ontario Federation of Anglers and Hunters|year=2024|access-date=24 March 2024}}</ref>  Another noticeable difference is that bowfin scales do not continue uniformly from their body to their head. Bowfin heads are smooth and free of scales, whereas the northern snakehead has scales that uniformly continue from their body through to their head.<ref>{{Cite web|title=Bowfin vs Snakehead 101: How to tell the difference between these two fish {{!}} Wild Hydro|date=3 November 2021|url=https://wildhydro.com/bowfin-vs-snakehead/|access-date=2021-11-10|language=en-US}}</ref>

The [[burbot]] (''Lota lota''), a [[predator]]y fish native to streams and lakes of North America and Eurasia, is also commonly mistaken for bowfin. Burbots can be distinguished by their flat head and chin barbel, long anal fin, and pelvic fins situated beneath the pectoral fins.<ref name="WiDNR">{{cite web | url=http://dnr.wi.gov/lakes/cbcw/publications/FH-715.pdf | title=Snakehead, Bowfin, or Burbot&nbsp;— Know the difference | publisher=Wisconsin Dept. of Natural Resources | work=Wisconsin Anglers Want To Know brochures | access-date=June 14, 2014 | author=Bureau of Fisheries Management}}</ref>

==Bowfin body-shape evolution and development==
The first fish lacked jaws and used negative pressure to suck their food in through their mouths. The jaw in the bowfin is a result of their evolutionary need to be able to catch and eat bigger and more nutritious prey. As a result of being able to gather more nutrients, Bowfin are able to live a more active lifestyle. The jaw of a bowfin has several adaptations. The maxilla and premaxilla are fused and the posterior chondrocranium articulates with the vertebra which allows the jaw freedom to rotate. The suspensorium includes several bones and articulates with the snout, brain case, and the mandible. When the jaw opens [[Epaxial and hypaxial muscles|epaxial muscles]] lift the chondrocranium, which is attached to the upper jaw, while [[Adductor muscles (bivalve)|adductor muscles]] act to close the lower jaw. This ability to open and close the jaw helps the bowfin to be an active predator that can catch bigger prey and digest them.<ref name=Kardong-2015-Vrtb>
{{cite book
 |last=Kardong |first=Kenneth V.
 |year=2015
 |title=Vertebrates: Comparative anatomy, function, evolution
 |place=New York, NY |publisher=McGraw-Hill Education
}}
</ref>

The [[vertebral column]] in bowfin is ossified and in comparison to earlier fish, the [[wiktionary:centrum#English|centra]] are the major support for the body, whereas in earlier fish the notochord was the main form of support. In bowfin neural spines and ribs also increase in prominence, an evolutionary aspect that helps provide additional support and stabilize unpaired fins. The evolution of the vertebral column allows the bowfin to withstand lateral bending that puts the column under compression without breaking. This, in turn, allows the bowfin to have more controlled and powerful movements, in comparison to fish that had only a notochord. The bowfin has a rounded heterocercal tail that resembles a homocercal tail. This type of tail gives the body a streamlined shape which allows the bowfin to improve its swimming ability by reducing drag. These types of tails are common in fish with gas bladders, because the bladder supplies the fish with natural buoyancy.<ref name=Kardong-2015-Vrtb/>
[[File:Hal - Cyprinus carpio and Amia calva skeletons.jpg |thumb|The lower figure is a skeleton of the bowfin. The pelvic and pectoral girdles are both visible and the axial and cranial elements are also both present.]]
The bowfin is a member of [[actinopterygii]] which means that the pectoral girdle is partly [[Endochondral ossification|endochondral]] but mostly [[dermal bone]]. In this group of fish the fins function to maneuver, brake, and for slight positional adjustments. The pectoral girdle of the bowfin has six parts. The post temporal, supracleithrum, postcleithrum, cleithrum, scapulacoracoid, and the clavicle make up the [[pectoral girdle]]. The pectoral girdle is attached to the skull. The paired pectoral and pelvic fins of fish are homologous with the limbs of tetrapods.<ref name=Kardong-2015-Vrtb/>

==Physiology==
[[File:Amia Gas Bladder.jpg|thumb|Dissection of a bowfin [[swim bladder]]]]
Bowfin are [[physostome]]s, meaning they have a small "[[pneumatic duct]]" that connects their [[swim bladders]] to their digestive tract. This allows them, like [[lungfish]], to "breathe" in two ways: they can extract oxygen from the water when breathing through their [[gills]], but can also break the water's surface to breathe or gulp air through the [[pneumatic duct]].<ref name="WaEDU05">{{cite web |title=Swimbladder |publisher=University of Washington |place=Seattle, WA |series=Biology of Fish |department=Fish / Biol 311 |type=class notes  |url=http://courses.washington.edu/fish311/FISH%20311%20files/05-Swimbladder.pdf |access-date=2 August 2014 |url-access=registration}}</ref><ref name=NCB>{{cite journal |author1=Hedrick, M.S. |author2=Jones, D.R. |date=January 1999  |title=Control of gill ventilation and air-breathing in the bowfin ''Amia calva'' |journal=J. Exp. Biol. |volume=202 |issue=1 |pages=87–94 |pmid=9841898 |doi=10.1242/jeb.202.1.87 |doi-access=free}}</ref> When performing low-level physical activity, bowfin obtain more than half of their oxygen from breathing air.<ref name=farmer1998>{{cite journal |last1=Jackson |first1=D.C. |first2=C.G. |last2=Farmer |date=March 5, 1998 |title=Air-breathing during activity in the fish ''Lepisosteus oculatus'' and ''Amia calva'' |journal=The Journal of Experimental Biology |issue=201 |pages=943–948 |url=http://jeb.biologists.org/content/201/7/943.full.pdf |access-date=8 June 2014}}</ref> The fish have two distinct air-breathing mechanisms used to ventilate the gas bladder. Air breathing ''type&nbsp;I'' is consistent with the action of exhale / inhale exchange, stimulated by either air or [[Hypoxia (environmental)|water hypoxia]], to regulate {{O2}} gas exchange; ''type&nbsp;II'' air breaths are inhalation alone, which is believed to regulate gas bladder volume, to control [[buoyancy]].<ref name=NCB/> Bimodal respiration helps bowfin survive and maintain their metabolic rate in [[Dead zone (ecology)|hypoxic]] (low-oxygen) conditions.<ref name=Bimodal>{{cite book |author=Boutilier, R.G. |chapter=Control and Co-Ordination of Gas Exchange in Bimodal Breathers |author-link=Robert Boutilier |year=1990 |title=Vertebrate Gas Exchange |series=Advances in Comparative and Environmental Physiology |volume=6 |pages=279–345 |doi=10.1007/978-3-642-75380-0_9 |isbn=978-3-642-75382-4}}</ref><ref name="JEB">{{cite journal |author1=McKenzie, David J. |author2=Steffensen, John F. |author3=Taylor, Edwin W. |author4=Abe, Augusto S.  |date=19 December 2011 |name-list-style=amp |title=The contribution of air breathing to aerobic scope and exercise performance in the banded knifefish ''Gymnotus carapo L.'' | volume=215 | issue=8 | journal=Journal of Experimental Biology |pages=1323–1330, Introduction |doi=10.1242/jeb.064543 |pmid=22442370 |doi-access=free}}</ref><ref name="Envirothon">{{cite web |title=Canon Envirothon Water Quality Study |year=2005 |department=Water Quality Assessment Division |publisher=Louisiana Department of Environmental Quality |access-date=June 13, 2014 |page=18 |url=http://deq.louisiana.gov/portal/Portals/0/assistance/Envirothon%20Study%20Guide%20Text.pdf |url-status=live |archive-url=https://web.archive.org/web/20130413112931/http://www.deq.louisiana.gov/portal/Portals/0/assistance/Envirothon%20Study%20Guide%20Text.pdf |archive-date=April 13, 2013}}</ref> Bowfin air breathe more frequently when they are in darkness, and correspondingly more active.<ref name=FishesWI/>

Bowfin blood can adapt to warm, [[acid]]ic waters.<ref name=Stauffer-2007-FshWV/> The fish becomes inactive in waters below {{convert|10|C|F|abbr=on}};<ref name=Stauffer-2007-FshWV/> at this temperature they breathe almost no air; however, with increasing temperature their air breathing increases.<ref name=FishesWI/> Their preferred temperature range is between {{convert|12|-|26|C|F|abbr=on}}, with {{convert|18|C|F|abbr=on}} the temperature of maximum activity.<ref name=Ross2001>
{{cite book
 |author=Ross, Stephen T.
 |year=2001
 |title=The Inland Fish of Mississippi
 |publisher=Univ. Press of Mississippi
 |isbn=978-1-57806-246-1
 |url=https://books.google.com/books?id=WEaKXWRt10kC&pg=PA94
 |page=94
}}
</ref> Air breathing is at a maximum in the range {{convert|18.4|-|29.6|C|F|abbr=on}}. Bowfin do not use [[Central chemoreceptors|central chemoreceptor]] regulation for respiration control. Experiments manipulating the oxygen content, carbon dioxide content, and pH of bowfin extradural fluid did not affect breathing rate, heart rate, or blood pressure pointing to a lack of central chemoreceptor regulation.<ref>{{Cite journal|last1=HEDRICK|first1=M. S.|last2=BURLESON|first2=M. L.|last3=JONES|first3=D. R.|last4=MILSOM|first4=W. K.|date=1991-01-01|title=An Examination of Central Chemosensitivity in an Air-Breathing Fish (Amia Calva)|journal=Journal of Experimental Biology|volume=155|issue=1|pages=165–174|doi=10.1242/jeb.155.1.165|issn=0022-0949}}</ref> Instead, bowfin respiratory patterns respond to water oxygen content and water temperature, as water temperatures play a role in oxygen content. In the lab, bowfin showed an increase in the breathing rate when the temperatures were raised above 10&nbsp;°C.<ref>{{Cite journal|last1=Horn|first1=M. H.|last2=Riggs|first2=C.|date=1973|title=Effects of Temperature and Light on the Rate of Air Breathing of the Bowfin, Amia calva|journal=Copeia| volume=1973 |issue=4|pages=653–657|doi=10.2307/1443063|jstor=1443063|s2cid=86886787}}</ref> Bowfin also showed an increase in breathing rate when exposed to lower oxygen levels in the water.<ref>{{Cite book|date=2009|editor-last=Glass|editor-first=Mogens L.|editor2-last=Wood|editor2-first=Stephen C.|title=Cardio-Respiratory Control in Vertebrates|url=https://link.springer.com/book/10.1007/978-3-540-93985-6|language=en-gb|doi=10.1007/978-3-540-93985-6|isbn=978-3-540-93984-9}}</ref>

Herpetologist [[Wilfred T. Neill|W. T. Neill]] reported in 1950 that he unearthed a bowfin [[aestivation|aestivating]] (in a dormant state) in a chamber {{Convert|4|in|cm}} below the ground surface, {{Convert|8|in|cm}} in diameter, {{Convert|.25|mi|km|1}} from a river. It was further noted that flood levels had previously reached the area, and receded. It is not unusual for riverine species like bowfin to move into backwaters with flood currents, and become trapped when water levels recede.<ref name=FishesWI>{{cite web |publisher=University of Wisconsin |department=Wisconsin State Department of Natural Resources |title=Bowfin Family-Amiidae |page=254 |url=http://images.library.wisc.edu/EcoNatRes/EFacs/FishesWI/reference/econatres.fisheswi.i0020.pdf |access-date=8 June 2014}}</ref><ref>{{cite book |title=Copeia, 1950, An estivating bowfin |first=W.T. |last=Neill |author-link=Wilfred T. Neill |page=240 |date=1950  |publisher=American Society of Ichthyologists and Herpetologists|url=https://books.google.com/books?id=eVeaSqFy2VgC&q=neill+1950+An+estivating+bowfin&pg=PA21 |isbn=978-0-521-73967-2 }}</ref><ref>{{cite web |author1=Loftus, William F. |author2=Kushlan, James A. |publisher=Florida State Museum Biological Sciences |title=Freshwater fish of southern Florida |page=183 |volume=31 |date=1987 |issue=4 |url=http://ufdc.ufl.edu/UF00001474/00001/39j}}</ref><ref name=Floodplain>{{cite report |url=http://floridarivers.ifas.ufl.edu/RiverClass/Papers/Junk_et_al._1989.pdf |publisher=University of Florida |title=The Flood Pulse Concept in River-Floodplain Systems |author1=Wolfgang J. Plunk |author2=Peter B. Bayley |author3=Richard E. Sparks |pages=117, 8–pdf |date=1989 |access-date=2014-06-09 |archive-date=2010-06-21 |archive-url=https://web.archive.org/web/20100621031012/http://floridarivers.ifas.ufl.edu/RiverClass/Papers/Junk_et_al._1989.pdf }}</ref> While aestivation is anecdotally documented by multiple researchers, laboratory experiments have suggested instead that bowfin are physiologically incapable of surviving more than three to five days of air exposure. However, no field manipulation has been performed.<ref name="McKenzie1990">{{Cite journal | doi = 10.1007/BF00004442| pmid = 24221948| title = Does ''Amia calva'' aestivate?| journal = Fish Physiology and Biochemistry| volume = 8| issue = 2| pages = 147–58| year = 1990| last1 = McKenzie | first1 = D. J. | last2 = Randall | first2 = D. J. | bibcode = 1990FPBio...8..147M| s2cid = 20401237}}</ref><ref name=Helfman>{{cite book |publisher=Wiley-Blackwell |title=The Diversity of Fish: Biology, Evolution, and Ecology |url=https://archive.org/details/diversityfishesb00helf |url-access=limited |author1=Gene Helfman |author2=Bruce B. Collette |author3=Douglas E. Facey |author4=Brian W. Bowen |page=[https://archive.org/details/diversityfishesb00helf/page/n273 257], Chapter 13 |date=2009|isbn=978-1-4051-2494-2 }}</ref> Regardless of the lack of evidence confirming the bowfin's ability to aestivate, it has been noted that bowfin can survive prolonged conditions of exposure to air because they have the ability to breathe air. Their gill filaments and [[Lamella (surface anatomy)|lamellae]] are rigid in structure which helps prevent the lamellae from collapsing and aids gas exchange even during air exposure.<ref name="Warren">{{cite book | url=https://books.google.com/books?id=iUrcAwAAQBAJ&pg=PA288 | title=Freshwater Fish of North America | publisher=JHU Press | volume=1: Petromyzontidae to Catostomidae | date=July 2014 |author1=Melvin L. Warren Jr. |author2=Brooks M. Burr | pages=288–289| isbn=978-1-4214-1201-6 }}</ref>

==Evolution and phylogeny==
Competing [[hypotheses]] and debates continue over the evolution of ''Amia'' and relatives, including their relationship among basal extant teleosts, and organization of [[clade]]s.<ref name="JVP">{{cite journal | title=The Sister-Group of Teleostei: Consensus And Disagreements | author=Arratia, Gloria | journal=Journal of Vertebrate Paleontology | year=2001 | volume=21 | issue=4 | pages=767–773 | doi=10.1671/0272-4634(2001)021[0767:TSGOTC]2.0.CO;2| s2cid=85895344 }}</ref> Bowfin are the last remaining member of [[Halecomorphi]], a group that includes many extinct species in several families.<ref name="RSP">{{cite journal | title=The oldest ionoscopiform from China sheds new light on the early evolution of halecomorph fish |author1=Guang-Hui Xu |author2=Li-Jun Zhao |author3=Michael I. Coates | journal=Biology Letters |date=May 2014  | doi=10.1098/rsbl.2014.0204 | volume=10 | issue = 5 | pmid=24872460 | pmc=4046378 | article-number=20140204}}</ref> Halecomorphs were generally accepted as the [[sister group]] to [[Teleostei]] but not without question. While a halecostome pattern of [[Neopterygii|neopterygian]] clades was produced in morphology-based analyses of extant [[actinopterygian]]s, a different result was produced with fossil taxa which showed a [[monophyletic]] Holostei. Monophyletic Holostei were also recovered by at least two [[nuclear gene]] analyses, in an independent study of fossil and extant fish,<ref name="RSPBS">{{cite journal | title=A New Time-Scale for Ray-Finned Fish Evolution | author=Imogen A. Hurley | author2=Rachel Lockridge Mueller | author3=Katherine A. Dunn | author4=Eric J. Schmidt | author5=Matt Friedman| author6=Robert K. Ho | author7=Victoria E. Prince | author8=Ziheng Yang | author9=Mark G. Thomas | author10=Michael I. Coates | name-list-style=amp| journal=  Proceedings of the Royal Society B: Biological Sciences|date=February 2007  | volume=274 | issue=1609 | pages=489–498 | doi=10.1098/rspb.2006.3749 | pmid=17476768 | jstor=25223804| pmc=1766393 }}</ref><ref name="Broughton2013">{{cite journal | doi = 10.1371/currents.tol.2ca8041495ffafd0c92756e75247483e | pmid=23788273 | pmc=3682800 | title=Multi-locus phylogenetic analysis reveals the pattern and tempo of bony fish evolution | journal=PLOS Currents | volume=5 | date=2013 | first=Richard E. | last=Broughton | doi-broken-date=5 July 2025 | doi-access=free }}</ref> and in an analysis of ultraconserved genomic elements.<ref name="Faircloth2013">{{cite journal | doi = 10.1371/journal.pone.0065923 | title=A Phylogenomic Perspective on the Radiation of Ray-Finned Fish Based upon Targeted Sequencing of Ultraconserved Elements (UCEs) | journal=PLOS ONE | date=2013 | volume=8 | issue=6 | article-number=e65923 | first=Brant C. | last=Faircloth | pmid=23824177 | pmc=3688804| bibcode=2013PLoSO...865923F | doi-access=free }}</ref>

The extant ray-finned fish of the subclass Actinopterygii include 42 orders, 431 families and over 23,000 species.<ref name=UofE>{{cite web| url=http://www.nhc.ed.ac.uk/index.php?page=493.470.483.472.2 | publisher=University of Edinburgh | title=SUBCLASS ACTINOPTERYGII: RELICT SPECIES OF RAY-FINNED FISH & ORIGIN OF TELEOSTS | date = January 2007 | access-date=September 29, 2014}}</ref> They are currently classified into two infraclasses, [[Chondrostei]] ([[holosteans]]) and [[Neopterygii]] (teleost fishes).<ref name="BMC">{{cite journal | title=Basal jawed vertebrate phylogeny inferred from multiple nuclear DNA-coded genes | volume=2 | issue=1 | page=3 | journal= BMC Biology| date=March 11, 2004 |author1=Kanae Kikugawa |author2=Kazutaka Katoh |author3=Shigehiro Kuraku |author4=Hiroshi Sakurai |author5=Osamu Ishida |author6=Naoyuki Iwabe |author7=Takashi Miyata | doi=10.1186/1741-7007-2-3| pmid=15070407 | pmc=387836 | doi-access=free }}</ref> Sturgeons, paddlefish, bichirs and reed fish compose the thirty-eight species of chondrosteans, and are considered relict species. Included in the over 23,000 species of neopterygians are eight relict species comprising gars and the bowfin.<ref name=UofE/>

[[File:Cladogram of basal actinopterygians and neopterygians.png|thumb|upright=1.8<!--set width for low-height image-->|Three divisions of [[Neopterygii]] comprising [[Lepisosteiformes]], [[Amiiformes]], and [[Teleostei]]]]

===Infraclass Neopterygii===
[[Neopterygii|Neopterygians]] are the second major occurrence in the evolution of ray-finned fish and today include the majority of modern bony fish.<ref name=UofE/> They are distinguished from their earlier ancestors by major changes to the jaws, shape of the skull, and tail. They are divided into three divisions:
* Division 1. Order [[Lepisosteiformes]]&nbsp;– the relict gars which include extant species of [[gar]]s that first appeared in the [[Cretaceous]].
* Division 2. Order [[Amiiformes]]&nbsp;– the relict bowfin, ([[halecomorphi]]ds), the only extant species in the order [[Amiiformes]] which date back to the [[Triassic period]].
* Division 3. Division Teleostei&nbsp;– the [[stem group]] of [[Teleostei]] from which modern fish arose, including most of the [[bony fish]] we are familiar with today.<ref name=Neopterygians>{{cite book|url=https://books.google.com/books?id=8djlBZhJ0nkC&pg=PA144|publisher=Chelsea House Publishers|title=The First Vertebrate|author=Thom Holmes|page=144|date=June 28, 2008|isbn=978-0-8160-5958-4}}</ref>

===Species===
The following  is a species list{{citation needed|date=December 2021}}
{{div col |colwidth=15em |content=

* †''Amia depressa'' <small>Marsh 1871</small>
* †''Amia dictyocephala'' <small>Cope 1875</small>
* †''Amia elegans'' <small>Leidy 1873</small>
* †''Amia exilis'' <small>Lambe 1908</small>
* †''Amia fragosa'' <small>(Jordan 1927)</small>
* †''Amia godai'' <small>Yabumoto & Grande 2013</small>
* †''Amia gracilis'' <small>Leidy 1873</small>
* †''Amia lewesiensis'' <small>Mantell 1822</small>
* †''Amia macrospondyla'' <small>Cope 1891</small>
* †''Amia media'' <small>Leidy 1873</small>
* †''Amia morini'' <small>Priem 1911</small>
* †''Amia newberriana'' <small>Marsh 1871</small>
* †''Amia selwyniana'' <small>Ami 1891</small>
* †''Amia uintaensis'' <small>Leidy 1873</small>
* †''Amia whiteavesiana'' <small>Cope 1891</small>
* †''Amia pattersoni'' 
* †''Amia scutata'' <small>Cope 1875</small>
* ''Amia calva'' <small>Linnaeus 1766</small> (Bowfin)
* ''[[Amia ocellicauda]]'' <small>Todd 1837</small> (Eyetail bowfin)<ref name="Brownstein"/>

}}

===Genome evolution===
The bowfin [[genome]] contains an intact [[ParaHox]] [[gene cluster]], similar to the [[bichir]] and to most other [[vertebrate]]s. This is in contrast, however, with [[teleost]] fish, which have a fragmented ParaHox cluster, probably because of a [[whole genome duplication]] event in their lineage. The presence of an intact ParaHox gene cluster suggests that bowfin ancestors separated from other fish before the [[last common ancestor]] of all [[teleost]]s appeared. Bowfin are thus possibly a better model to study vertebrate genome organization than common teleost [[model organism]]s such as [[zebrafish]].<ref name=Mulley-Chiu-Holland-2006/>

==Feeding behavior==
[[File:Gill Rakers of Amia Calva.jpg|thumb|The [[gill raker]]s are short with blunt processes and with a small space in between them. They are connected to the gill arch of the gills.]]
Bowfin are stalking, ambush predators that customarily move into the shallows at night to prey on fish, amphibians, and aquatic invertebrates such as crawfish, other crustaceans, mollusks, and aquatic insects.<ref name="InDFW">{{cite web | url=http://www.in.gov/dnr/fishwild/files/fw-bowfin.pdf | title=Bowfin (Amia calva) | publisher=Indiana Department of Natural Resources | access-date=June 13, 2014 | author=Indiana Department of Fish & Wildlfife}}</ref><ref name="ADW"/> Young bowfin feed mostly on small [[crustaceans]], while adults are mostly [[piscivorous]], but also known to be opportunistic.<ref name=Arndt-Folt-2009-FrFshSC/> Some common examples of prey include frogs, bass, other bowfin, dragonflies, sunfish, crawfish, etc.<ref name="ADW"/> Bowfin are remarkably agile, can move quickly through the water, and they have a voracious appetite.<ref name=Stewart-Watkinson-2004/><ref name=Schultz-2010/> Their undulating dorsal fin propels them silently through the water while stalking their prey. The attack is straightforward and swift with a movement that lasts approximately 0.075 seconds.<ref name=Ross2001/> There were also some studies regarding the capacity of the bowfin to survive without food. In 1916, a female bowfin was starved for twenty months.<ref name=Smallwood-1916-01-01/> It was the longest period that any vertebrate had been without food, as far the writer was aware during the observation. Some independent studies focus on the bowfin's ability to use organic material as a source of food and studied the structure of the [[gill raker]]. They concluded that it did not benefit from the organic material in the water because the gill rakers were short with blunt processes and a short space between them. Even bacteria could enter and exit through the gill easily. Its structure alone indicated that the ''Amia'' do not use microorganisms as a source of food.{{citation needed|date=August 2019}}

==Distribution and habitat==
[[File:USGSmapBowfinDist.png|thumb|''Amia calva'' distribution in the eastern U.S., as well as from the [[St. Lawrence River]] and [[Lake Champlain]] drainage of southern [[Ontario]] and [[Quebec]], westward around Great Lakes in southern Ontario into Minnesota. ''Nota bene'': this includes populations now known to be ''[[Amia ocellicauda]].'']]

Fossil deposits indicate amiiforms included freshwater and marine species that were once widely distributed in North America, South America, Eurasia and Africa.<ref name=Hart-Reynolds-2002-HFB/> Today, the two species of ''Amia'' are the only remaining species in the order Amiiformes; they are [[Demersal fish|demersal]] freshwater [[piscivore]]s, and their range is restricted to freshwater environments in North America, including much of the eastern [[United States]] and adjacent southern Canada from the [[St. Lawrence River]] and [[Lake Champlain]] drainage of southern [[Ontario]] and [[Quebec]] westward around the [[Great Lakes]] in southern Ontario into Minnesota.<ref name=iucn/><ref name="USGS">{{cite web | url=https://nas.er.usgs.gov/queries/factsheet.aspx?SpeciesID=305 | title=''Amia calva'' Linnaeus, 1766| publisher=US Geological Survey|location=Gainesville, Florida| work=USGS Nonindigenous Aquatic Species Database |orig-date=Peer reviewed on 11 April 2006|date=31 March 2020| access-date=24 March 2024| author=Fuller, Pam}}</ref>

Historically, their distribution in North America included the [[drainage basin]]s of the [[Mississippi River]] from Quebec to northern Minnesota, the St. Lawrence-Great Lakes, including [[Georgian Bay]], [[Lake Nipissing]] and [[Lake Simcoe|Simcoe]], Ontario, south to the [[Gulf of Mexico]]; Atlantic and [[Gulf Coastal Plain]] from the [[Susquehanna River]] drainage in southeastern [[Pennsylvania]] to the [[Colorado River (Texas)|Colorado River]] in [[Texas]].<ref name="FishesWI"/><ref name="USGS"/><ref name="Acorn2007">{{cite book|author=John Acorn|title=Deep Alberta: Fossil Facts and Dinosaur Digs|url=https://archive.org/details/deepalbertafossi00acor|url-access=registration|date=7 February 2007|publisher=University of Alberta|isbn=978-0-88864-481-7|page=[https://archive.org/details/deepalbertafossi00acor/page/10 10]}}</ref>

===Stocking===
Research from the late 1800s to the 1980s suggests a trend of intentional stockings of non-indigenous fish into ponds, lakes and rivers in the United States. At that time, little was known about environmental impacts, or long-term effects of new species establishment and spread as a result of "fish rescue and transfer" efforts, or the importance of nongame fish to the ecological balance of aquatic ecosystems.<ref name=WFFM-UoWI-i0008-p29/> Introductions of bowfin to areas they were considered a non-indigenous species included various lakes, rivers and drainages in Connecticut, Delaware, Georgia, Illinois, Iowa, Kansas, Kentucky, Maryland, Massachusetts, Minnesota, Missouri, New Jersey, New York, North Carolina, Ohio, Oklahoma, Pennsylvania, Virginia, West Virginia, and Wisconsin.<ref name="USGS"/>  Many of the introductions were intentional stockings; however, there is no way to positively determine distribution resulting from flood transfers, or other inadvertent migrations. Bowfin are typically piscivorous, but as an introduced species are capable of being voracious predators that pose a threat to native fish and their prey.<ref name="USGS"/><ref name="FAO">{{cite web | url=http://www.fao.org/docrep/005/y3610e/y3610e12.htm | title=Potential Adverse Socio-Economic And Biological Impacts Of Aquatic Animal Pathogens Due To Hatchery-Based Enhancement Of Inland Open-Water Systems, And Possibilities For Their Minimisation | publisher=Inland Water Resources and Aquaculture Service | work=Primary aquatic animal health care in rural, small-scale, aquaculture | access-date=August 9, 2014 |author1=J. Richard Arthur |author2=Rohana P. Subasinghe }}</ref>

===Preferred habitat===
Bowfin prefer vegetated sloughs, lowland rivers and lakes, swamps, backwater areas, and are occasionally found in brackish water. They are well camouflaged, and not easy to spot in slow water with abundant vegetation. They often seek shelter under roots, and submerged logs.<ref name=Arndt-Folt-2009-FrFshSC/><ref name=Miller-Robison-2004-FshOkl/><ref name="LaermFreeman2008">{{cite book|author1=Joshua Laerm|author2=B. J. Freeman|title=Fish of the Okefenokee Swamp|url=https://books.google.com/books?id=8S7A45Gix6MC&pg=PA37|date=January 2008|publisher=University of Georgia Press|isbn=978-0-8203-3135-5|page=37}}</ref> Oxygen-poor environments can be tolerated because of their ability to breathe air.<ref name=Arndt-Folt-2009-FrFshSC/>

==Life cycle==
Bowfin spawn in the spring or early summer, typically between April and June, more commonly at night<ref name="Ross2001"/><ref name=Arndt-Folt-2009-FrFshSC/> in abundantly vegetated, clear shallow water in weed beds over sand bars, and also under stumps, logs, and bushes.<ref name=Thomas-Bonner-Whiteside-2007-06-18-FrFshTx/>
Optimum temperatures for nesting and spawning range between {{convert|16|-|19|C|F|abbr=on}}.<ref name="FLMNH"/> The males construct circular nests in fibrous root mats, clearing away leaves and stems. Depending on the density of surrounding vegetation there may be a tunnel-like entrance at one side.<ref name=Thomas-Bonner-Whiteside-2007-06-18-FrFshTx/> The diameter of the nests commonly range between {{convert|39|-|91|cm|in|abbr=on}},<ref name="FLMNH"/> at a water depth of {{convert|61|-|92|cm|in|abbr=on}}.<ref name="Ross2001"/>

During spawning season, the fins and underside of male bowfin often change in color to a bright lime green.<ref name=Jackson-DEC-NY-77506/> The courtship/spawning sequence lasts one to three hours, and can repeat up to five times.<ref name="Ross2001"/> Courtship begins when a female approaches the nest. The ritual consists of intermittent nose bites, nudges, and chasing behavior by the male until the female becomes receptive,<ref name="FLMNH"/> at which time the pair lie side by side in the nest. She deposits her eggs while he shakes his fins in a vibratory movement, and releases his milt for fertilization to occur.<ref name="FLMNH"/> A male often has eggs from more than one female in his nest, and a single female often spawns in several nests.<ref name="ADW"/>

Females vacate the nest after spawning,<ref name=Ross2001/> leaving the male behind to protect the eggs during the eight to ten days of incubation.<ref name=Schultz-2010/><ref name=Thomas-Bonner-Whiteside-2007-06-18-FrFshTx/><ref name=Berra-2001-FrWFshDist/> A nest may contain 2,000 to 5,000 eggs, possibly more.<ref name=Miller-Robison-2004-FshOkl/> [[Fecundity]] is usually related to size of the fish, so it is not unusual for the roe of a large gravid female to contain over 55,000 eggs.<ref name=Ross2001/><ref name=Arndt-Folt-2009-FrFshSC/> Bowfin eggs are adhesive, and will attach to aquatic vegetation, roots, gravel, and sand.<ref name="Ross2001"/> After hatching, larval bowfin do not swim actively in search of food. During the seven to nine days required for yolk-sac absorption, they attach to vegetation by means of an adhesive organ on their snout, and remain protected by the parent male bowfin.<ref name=Miller-Robison-2004-FshOkl/> Bowfin aggressively protect their spawn from the first day of incubation to a month or so after the eggs have hatched.<ref name=Miller-Robison-2004-FshOkl/> When the fry are able to swim and forage on their own, they will form a school and leave the nest accompanied by the parent male bowfin who slowly circles them to prevent separation.<ref name=Thomas-Bonner-Whiteside-2007-06-18-FrFshTx/>

Bowfin reach sexually maturity at two to three years of age.<ref name=Arndt-Folt-2009-FrFshSC/> They can live up to 33 years in the wild,<ref name=":3" /> and 30&nbsp;years in captivity.<ref name=Schultz-2010/><ref name=Thomas-Bonner-Whiteside-2007-06-18-FrFshTx/> Bowfin may live decades at adult size.<ref name=":3" />

==Diseases==
[[File:Lernaea parasite on a Murray cod.jpg|thumb|''Lernaea'', or [[anchor worm]], on a [[Murray cod]]. The same parasite also attacks bowfin.]]
A common [[parasite]] of bowfin is the [[anchor worm]] (''Lernaea''). These small crustaceans infest the skin and bases of fins, with consequences ranging from slowed growth to death.<ref name="FLMNH"/> The mollusk ''[[Unionidae|Megalonaias gigantea]]'' lays eggs in the bowfin gills, that are then externally fertilized by sperm passing in the water flow. The small [[glochidia]] larvae then hatch and develop in the gill tubes.<ref name="FLMNH"/>

Bowfin with [[liver cancer]] and with fatal [[leukemia]] have been reported.<ref name=Stauffer-2007-FshWV/>

==Utilization==
[[File:Bowfin (Amia calva) (4015394787).jpg|thumb|Freshly caught bowfin]]
As a sport fish, bowfin are not considered desirable to many [[angling|anglers]]. They were once considered a nuisance fish by anglers and early biologists who believed the bowfin's predatory nature was harmful to sport fish populations. As a result, efforts were taken to reduce their numbers.<ref name="NYS"/> Research has since proven otherwise, and that knowledge together with a better understanding of maintaining overall balance of ecosystems, regulations were introduced to help protect and maintain viable populations of bowfin.<ref name=NYS>{{cite web|url=http://www.dec.ny.gov/animals/77506.html|title=The Bowfin, New York's Disrespected Living Fossil|publisher=New York Department of Environmental Conservation|author=Randy Jackson|access-date=June 4, 2014|archive-date=April 27, 2021|archive-url=https://web.archive.org/web/20210427195817/https://www.dec.ny.gov/animals/77506.html}}</ref> Bowfin are strong fighters, a prized trait in game fish. However, they do have a jaw full of sharp teeth which requires careful handling. The current tackle record is {{convert|21.5|lb|kg|abbr=on}}<ref name=Stewart-Watkinson-2004/><ref name="Acorn2007"/><ref name="igfa">{{cite web|url=http://www.igfa.org/species/100-bowfin.aspx?CommonName=100-bowfin.aspx|title=Bowfin|publisher=International Game Fish Association|author=IGFA|access-date=June 4, 2014|archive-url=https://web.archive.org/web/20181012140152/https://www.igfa.org/species/100-bowfin.aspx?CommonName=100-bowfin.aspx|archive-date=October 12, 2018}}</ref>

Bowfin were once considered to have little commercial value because of its poor-tasting meat which has been referred to as "soft, bland-tasting and of poor texture".<ref name=Stewart-Watkinson-2004/> However, it is considered quite palatable if cleaned properly and [[smoking (food)|smoked]], or prepared fried, [[Blackening (cooking)|blackened]], used in [[Court-bouillon|courtbouillion]], or in fishballs or fishcakes.<ref name=Stewart-Watkinson-2004/><ref name=Schultz-2010/><ref name=Acorn2007/><ref name=Bourgeois-2009-04-05-DlyCmt/> Over the years, global efforts have imposed strict regulations on the international trade of caviar, particularly on the harvest of sturgeons from the Caspian Sea where the highly prized [[Beluga caviar|caviar]] from the [[beluga sturgeon]] originates. The bans imposed on Caspian sturgeons have created lucrative markets for affordable substitutes in the United States including [[American paddlefish|paddlefish]], bowfin, and various species of [[sturgeon]].<ref name=NYTimes-2012-06-10/> In [[Louisiana]], bowfin are harvested in the wild, and cultured commercially in hatcheries for their meat and roe. The roe is processed into caviar, and sold as "Cajun caviar", or marketed under the trade name "Choupiquet Royale".<ref name=Davis-2003-thesis-NSU/><ref name="Ross2001"/><ref name=Scharpf-bowfin-USFWS/>

==Accumulation of toxic substances==
In some areas of the United States where aquatic environments have tested positive for elevated levels of [[toxins]], such as [[Mercury (metal)|mercury]], [[arsenic]], [[chromium]], and [[copper]], there are posted signs with warnings about the consumption of fish caught in those areas.<ref name=EPA-fish-adv/> Concentration of mercury [[biomagnify|biomagnifies]] as it passes up the food chain from organisms on lower trophic levels to apex predators. It [[bioaccumulate]]s in the tissues of larger, long-lived predatory fish. When compared to smaller, short-lived fish, bowfin tend to concentrate mercury at higher levels thereby making them less safe for human consumption.<ref name=Davis-2003-thesis-NSU/><ref name=NCDPHS-safefish-sp-salud/>

==See also==
* [[Snakehead (fish)]]

==References==
{{reflist|25em |refs=

<ref name=Arndt-Folt-2009-FrFshSC>
{{cite book
 |first1=Rudolf G.  |last1=Arndt
 |first2=Jeffrey W. |last2=Foltz
 |year=2009
 |title=Freshwater Fish of South Carolina
 |publisher=Univ of South Carolina Press
 |isbn=978-1-57003-680-4
 |page=80
 |url=https://books.google.com/books?id=fVZHbQ7eJLQC&pg=PA80
}}
</ref>

<ref name=Berra-2001-FrWFshDist>
{{cite book
 |last=Berra |first=Tim M.
 |year=2001
 |title=Freshwater Fish Distribution
 |place=San Diego, CA
 |publisher=Academic Press
 |isbn=0-12-093156-7
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<ref name=Bourgeois-2009-04-05-DlyCmt>{{cite news
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}}  <!-- end "refs=" -->

==Further reading==
* {{cite journal | last1 = McCormick | first1 = Catherine A. | year = 1981 | title = Central Projects of the lateral line and eight nerves in the bowfin,''Amia Calva'' | url = https://deepblue.lib.umich.edu/bitstream/2027.42/50011/1/901970102_ftp.pdf| journal = The Journal of Comparative Neurology | volume = 197 | issue = 1| pages = 1–15 | doi=10.1002/cne.901970102| pmid = 6164698 | hdl = 2027.42/50011 | s2cid = 8836961 | hdl-access = free }}
* {{cite journal | last1 = Conlon | first1 = J.M. | last2 = Youson | first2 = J.H. | last3 = Whittaker | first3 = J. | year = 1991 | title = Structure and receptor-binding activity of insulin from a holostean fish, the bowfin:''Amia Calva'' | journal = Biochem. J. | volume = 276 | issue = Pt 1| pages = 261–264 | doi=10.1042/bj2760261| pmid = 2039477 | pmc = 1151174 }}
* {{cite journal | last1 = Nguyen | first1 = T. M. | last2 = Mommsen | first2 = T. P. | last3 = Mims | first3 = S. M. | last4 = Conlon | first4 = J. M. | year = 1994 | title = Characterization of insulins and proglucagon-derived peptides from a phylogenetically ancient fish, the paddlefish: ''Polyodon spathula'' | journal = Biochem. J. | volume = 300 | issue = 2| pages = 339–345 | doi=10.1042/bj3000339| pmid = 8002937 | pmc = 1138167 }}
* {{cite journal | last1 = Conlon | first1 = J. M. | last2 = Youson | first2 = J. H. | last3 = Mommsen | first3 = T. P. | year = 1993 | title = Structure and biological activity of glucagon and glucagon-like peptide from a primitive bony fish, the bowfin: '' Amia calva.'' | journal = Biochem. J. | volume = 295 | issue = 3| pages = 857–861 | doi=10.1042/bj2950857| pmid = 8240302 | pmc = 1134640 }}
* {{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 |access-date=2011-05-17 |archive-url=https://web.archive.org/web/20090220223520/http://strata.ummp.lsa.umich.edu/jack/showgenera.php?taxon=611&rank=class |archive-date=2009-02-20 }}

==External links==
{{Wikispecies|Amia calva}}
{{Commons}}
* [https://www.dnr.state.mn.us/fish/bowfin.html MN DNR]
* [https://web.archive.org/web/20070712154743/http://www.bowfinanglers.com/ Bowfin Anglers' Group]
* [http://www.fishbase.org/Summary/FamilySummary.cfm?ID=35 FishBase info for Amiidae]
* [http://academics.smcvt.edu/dfacey/AquaticBiology/Fishes%20Pages/Bowfin.html Bowfin info by Brent Courchene] {{Webarchive|url=https://web.archive.org/web/20110927122157/http://academics.smcvt.edu/dfacey/AquaticBiology/Fishes%20Pages/Bowfin.html |date=2011-09-27 }}

{{Actinopterygii}}
{{Halecomorphi|state=collapsed}}
{{Taxonbar|from=Q491934}}

[[Category:Amia (fish)]]
[[Category:Freshwater fish of North America|North America]]
[[Category:Fish of the Great Lakes]]
[[Category:Freshwater fish of the Southeastern United States]]
[[Category:Articles containing video clips]]
[[Category:Fish described in 1766]]