Sturgeon

{{Short description|Ray-finned fish}} {{other uses}} {{Use mdy dates|date=May 2019}} {{Automatic taxobox | name = Sturgeon | image = Acipenser oxyrhynchus (edit).png | image_caption = Atlantic sturgeon (''Acipenser oxyrinchus'') | fossil_range = {{fossilrange|Cenomanian|Recent}} | taxon = Acipenseridae | authority = Bonaparte, 1831 | subdivision_ranks = Genera | subdivision = *''Acipenser'' *''Sinosturio'' *''Huso'' *''Scaphirhynchus'' *''Pseudoscaphirhynchus'' Fossil genera: *†''Boreiosturion'' *†''Protoscaphirhynchus'' *†''Engdahlichthys'' *†''Anchiacipenser'' *†''Priscosturion'' }}

'''Sturgeon''' are the 27 species of fish belonging to the family '''Acipenseridae'''. The earliest sturgeon fossils date to the Late Cretaceous, and are descended from other, earlier acipenseriform fish, which date back to the Early Jurassic period, some 174 to 201 million years ago. They are one of two living families of the Acipenseriformes alongside paddlefish (Polyodontidae). The family is grouped into five genera: ''Acipenser'', ''Huso'', ''Scaphirhynchus,'' ''Sinosturio'', and ''Pseudoscaphirhynchus''.<ref name="CofFF">{{Cof family|family=Acipenseridae|access-date=28 May 2025|list=Species}}</ref><ref name=":2">{{Cite journal |last1=Brownstein |first1=Chase D. |last2=Near |first2=Thomas J. |date=2025-04-25 |title=Toward a Phylogenetic Taxonomy of Sturgeons (Acipenseriformes: Acipenseridae) |url=https://bioone.org/journals/bulletin-of-the-peabody-museum-of-natural-history/volume-66/issue-1/014.066.0101/Toward-a-Phylogenetic-Taxonomy-of-Sturgeons-Acipenseriformes-Acipenseridae/10.3374/014.066.0101.full |journal=Bulletin of the Peabody Museum of Natural History |volume=66 |issue=1 |doi=10.3374/014.066.0101 |issn=0079-032X|url-access=subscription }}</ref> Two species (''H. naccarii'' and ''S. dabryanus'') may be extinct in the wild, and one (''P. fedtschenkoi'') may be entirely extinct.<ref name="IUCN">{{cite web | url=http://www.iucn.org/?4928/Sturgeon-more-critically-endangered-than-any-other-group-of-species | title=Sturgeon More Critically Endangered Than Any Other Group of Species | publisher=International Union for Conservation of Nature | work=International News Release | date=March 18, 2010 | access-date=September 19, 2015 |author1=Chadwick, Niki |author2=Drzewinski, Pia |author3=Hurt, Leigh Ann }}</ref> Sturgeons are native to subtropical, temperate and sub-Arctic rivers, lakes and coastlines of Eurasia and North America.<ref name=WashingtonEdu>{{cite web|url=http://courses.washington.edu/fish311/FISH%20311%20files/08-Primitive%20bony.pdf|publisher=University of Washington|title=Biology of Fishes (chapter: Biodiversity II: Primitive Bony Fishes and The Rise of Modern Teleosts)|access-date=May 30, 2014}}</ref> A Maastrichtian-age fossil found in Morocco shows that they also once lived in northern Africa during the Cretaceous.<ref>{{Cite journal |last=Martill |first=D. M. |year=2023 |title=A sturgeon (Actinopterygii, Acipenseriformes) from the Upper Cretaceous of Africa |journal=Cretaceous Research |volume=148 |article-number=105546 |doi=10.1016/j.cretres.2023.105546 |bibcode=2023CrRes.14805546M |s2cid=257863907 }}</ref>

Sturgeons are long-lived, late-maturing fishes with distinctive characteristics, such as a heterocercal caudal fin similar to those of sharks, and an elongated, spindle-like body that is smooth-skinned, scaleless, and armored with five lateral rows of bony plates called scutes. Several species can grow quite large, typically ranging {{cvt|7|–|12|ft|m|round=0.5|order=flip}} in length. The largest sturgeon on record was a beluga female captured in the Volga Delta in 1827, measuring {{cvt|7.2|m|ftin}} long and weighing {{cvt|1,571|kg|lb}}. Most sturgeons are anadromous bottom-feeders, migrating upstream to spawn but spending most of their lives feeding in river deltas and estuaries. Some species inhabit freshwater environments exclusively, while others primarily inhabit marine environments near coastal areas, and are known to venture into open ocean.

Several species of sturgeon are harvested for their roe, which is processed into the luxury food caviar. This has led to serious overexploitation, which combined with other conservation threats, has brought most of the species to critically endangered status, at the edge of extinction.

== Etymology == The English word Sturgeon comes from Middle English {{lang|enm|sturgiun}} itself from Old French {{lang|fro|estorjoun}}, displacing Old English {{lang|ang|styrġa}} though both are derived from Proto-Germanic {{lang|gem-x-proto|*sturjô}}.<ref name="Etymological Dictionary of Proto-Germanic">{{cite book |last1=Kroonen |first1=Guus |title=Etymological Dictionary of Proto-Germanic |date=2013 |isbn=978-90-04-18340-7 |page=488 |url=https://archive.org/details/etymological-dictionary-of-proto-germanic/page/488/mode/2up}}</ref>

Apparent cognates to Sturgeon might be found in Baltic, Germanic, Greek, Romance, and Slavic languages. The trade of sturgeon in ancient Europe would cause for the root word for these to spread across the region. Many potential reconstructions may place it as either a non-Indo-European substrate language,<ref name="Etymological Dictionary of Proto-Germanic"/> possibly from around the Volga river, where sturgeon could be caught and sold, while others reconstruct a Proto-Indo-European source.

One reconstruction links Sturgeon to ultimately derive from Proto-Indo-European *''str̥(Hx)yón''-.<ref>{{cite book |page=550|title=Encyclopedia of Indo-European culture |first1=James P. |last1=Mallory |first2=Douglas Q. |last2=Adams |date=1997 |publisher=Fitzroy Dearborn |location=Chicago |isbn=1-884964-98-2 }}</ref>

== Evolution ==

===Fossil history=== [[File:Yanosteus longidorsalis MHNT (tighter crop).jpg|thumb|upright=1.25|''Yanosteus longidorsalis'', a member of the extinct acipenseriform family Peipiaosteidae from the Early Cretaceous (125–120 Mya) Yixian Formation in Liaoning, China]]

Acipenseriform fishes appeared in the fossil record some 174 to 201 million years ago, during the Early Jurassic, making them some of the earliest extant actinopterygian fishes.<ref name=":02">{{Cite journal|last1=Hilton|first1=Eric J.|last2=Grande|first2=Lance|last3=Jin|first3=Fan|date=January 2021|title=Redescription of † Yanosteus longidorsalis Jin et al., (Chondrostei, Acipenseriformes, †Peipiaosteidae) from the Early Cretaceous of China|url=https://www.cambridge.org/core/product/identifier/S0022336020000803/type/journal_article|journal=Journal of Paleontology|language=en|volume=95|issue=1|pages=170–183|doi=10.1017/jpa.2020.80|bibcode=2021JPal...95..170H |s2cid=225158727|issn=0022-3360|url-access=subscription}}</ref> Sturgeons must have diverged from their closest relatives, the paddlefish, during the Early Cretaceous (125-120 million years ago) or prior, as the earliest fossil paddlefish (''Protopsephurus'') is known from then.<ref name=":3">{{Cite journal |last1=Murray |first1=Alison M. |last2=Brinkman |first2=Donald B. |last3=DeMar JR |first3=David G. |last4=Wilson |first4=Gregory P. |date=2020-03-03 |title=Paddlefish and sturgeon (Chondrostei: Acipenseriformes: Polyodontidae and Acipenseridae) from lower Paleocene deposits of Montana, U.S.A. |journal=Journal of Vertebrate Paleontology |volume=40 |issue=2 |article-number=e1775091 |doi=10.1080/02724634.2020.1775091 |bibcode=2020JVPal..40E5091M |issn=0272-4634}}</ref> True sturgeons appear in the fossil record during the Upper Cretaceous, with amongst the oldest known remains being a partial skull from the Cenomanian (100–94 million years ago) of Alberta, Canada.<ref name=":4">{{Cite journal |last1=Vavrek |first1=Matthew J. |last2=Murray |first2=Alison M. |last3=Bell |first3=Phil R. |date=July 2014 |editor-last=Sues |editor-first=Hans-Dieter |title=An early Late Cretaceous (Cenomanian) sturgeon (Acipenseriformes) from the Dunvegan Formation, northwestern Alberta, Canada |url=http://www.nrcresearchpress.com/doi/10.1139/cjes-2014-0052 |journal=Canadian Journal of Earth Sciences |language=en |volume=51 |issue=7 |pages=677–681 |doi=10.1139/cjes-2014-0052 |bibcode=2014CaJES..51..677V |issn=0008-4077|url-access=subscription }}</ref> In that time, sturgeons have undergone remarkably little morphological change, indicating their evolution has been exceptionally slow and earning them informal status as living fossils.<ref>B. G. Gardiner (1984) Sturgeons as living fossils. Pp. 148–152 in N. Eldredge and S.M. Stanley, eds. Living fossils. Springer-Verlag, New York.</ref><ref name="krieger">{{cite journal|last1=Krieger|first1=J.|last2=Fuerst|first2=P.A.|year=2002|title=Evidence for a Slowed Rate of Molecular Evolution in the Order Acipenseriformes|journal=Molecular Biology and Evolution|volume=19|issue=6|pages=891–897|doi=10.1093/oxfordjournals.molbev.a004146|pmid=12032245|doi-access=free}}</ref> This is explained in part by the long generation interval, tolerance for wide ranges of temperature and salinity, lack of predators due to size and bony plated armor, or scutes, and the abundance of prey items in the benthic environment. They do, however, still share several primitive characteristics, such as heterocercal tail, reduced squamation, more fin rays than supporting bony elements, and unique jaw suspension.<ref name="HelfmanCollette2009">{{cite book|author1=Gene Helfman|url=https://books.google.com/books?id=FyehAR6hsUUC&pg=PA252|title=The Diversity of Fishes: Biology, Evolution, and Ecology|author2=Bruce B. Collette|author3=Douglas E. Facey|author4=Brian W. Bowen|date=April 3, 2009|publisher=John Wiley & Sons|isbn=978-1-4443-1190-7|pages=252–}}</ref>

===Phylogeny and taxonomy===

Despite the existence of a fossil record, full classification and phylogeny of the sturgeon species has been difficult to determine, in part due to the high individual and ontogenic variation, including geographical clines in certain features, such as rostrum shape, number of scutes, and body length. A further confounding factor is the peculiar ability of sturgeons to produce reproductively viable hybrids, even between species assigned to different genera. While ray-finned fishes (Actinopterygii) have a long evolutionary history culminating in the most familiar fishes, past adaptive evolutionary radiations have left only a few survivors, such as sturgeons and gars.<ref name="Craniata">{{cite web|title=Craniata, (2) Subclass Actinopterygii-the ray-finned fishes|url=http://userwww.sfsu.edu/biol240/labs/lab_21chordatediversity/pages/craniata.html|archive-url=https://web.archive.org/web/20130423002203/http://userwww.sfsu.edu/biol240/labs/lab_21chordatediversity/pages/craniata.html|archive-date=April 23, 2013|access-date=May 31, 2014|publisher=San Francisco State University}}</ref>

The phylogeny of Acipenseridae, as in the cladogram, shows that they evolved from the bony fishes. In currently accepted taxonomy, the class Actinopterygii and the order Acipenseriformes are both clades.<ref name="PNAS">{{cite journal|author=Thomas J. Near|display-authors=etal|date=2012|title=Resolution of ray-finned fish phylogeny and timing of diversification|journal=PNAS|volume=109|issue=34|pages=13698–13703|bibcode=2012PNAS..10913698N|doi=10.1073/pnas.1206625109|pmc=3427055|pmid=22869754|doi-access=free}}</ref><ref name="TOL">{{cite journal |last=Betancur |first=Ricardo |year=2013 |title=The Tree of Life and a New Classification of Bony Fishes |journal=PLOS Currents Tree of Life |volume=5 |issue=1 |doi=10.1371/currents.tol.53ba26640df0ccaee75bb165c8c26288 |pmc=3644299 |pmid=23653398 |hdl=2027.42/150563 |doi-access=free}}</ref><ref name="laurin&reisz1995">{{cite journal|author1=Laurin, M.|author2=Reisz, R.R.|year=1995|title=A reevaluation of early amniote phylogeny|journal=Zoological Journal of the Linnean Society|volume=113|issue=2|pages=165–223|doi=10.1111/j.1096-3642.1995.tb00932.x}}</ref> Approximate dates are from Near ''et al.'', 2012.<ref name="PNAS" />{{clade |label1=Osteichthyes |1={{clade |label1=Sarcopterygii |1={{clade |1=Coelacanths, lungfish 70 px |2=Tetrapods 70 px }} |label2=Actinopterygii |sublabel2={{small|400 mya}} |2={{clade |label1=Cladistia |1=Polypteriformes (bichirs, reedfishes) 80px |label2=Actinopteri |2={{clade |label1=Chondrostei |1={{clade |label1=Acipenseriformes |1={{clade |1='''Acipenseridae''' 90px |2=Polyodontidae 90px }} }} |label2=Neopterygii |sublabel2={{small|360 mya}} |2={{clade |label1=Holostei |sublabel1={{small|275 mya}} |1={{clade |1=Lepisosteiformes (gars) 70px |2=Amiiformes (bowfins) 70px }} |2=Teleostei 60px |sublabel2={{small|310 mya}} }} }} }} }} }}

The wide range of the acipenserids and their endangered status have made collection of systematic materials difficult. The factors have led researchers in the past to identify over 40 additional species that were rejected by later scientists.<ref name="bemis">{{cite journal |last1=Bemis |first1=W. E. |last2=Findeis |first2=E. K. |last3=Grande |first3=L. |year=1997 |title=An overview of Acipenseriformes |journal=Environmental Biology of Fishes |volume=48 |issue=1–4 |pages=25–71 |bibcode=1997EnvBF..48...25B |doi=10.1023/A:1007370213924 |s2cid=24961905}}</ref> An effort is ongoing to resolve the taxonomic confusion using a continuing synthesis of systematic data and molecular techniques.<ref name="krieger" /><ref name=":5">{{cite journal |last1=Fontana |first1=F. |last2=Tagliavini |first2=J. |last3=Congiu |first3=L. |year=2001 |title=Sturgeon genetics and cytogenetics: recent advancements and perspectives |journal=Genetica |volume=111 |issue=1–3 |pages=359–373 |doi=10.1023/a:1013711919443 |pmid=11841180 |s2cid=569847}}</ref> [[File:Goddard Scientific Colloquium, Tanis fish fossils.jpg|thumb|A fossil sturgeon (right) from the Tanis fossil site, showing the longstanding morphological conservatism of this group]] Sturgeons are a highly morphologically conservative group, to the extent that lineages that (based on molecular data) have been separate since the Cretaceous period can physically appear very similar, and mistakenly classified as each other's closest relatives. In the classic taxonomic treatment, Acipenseridae was subdivided into 2 subfamilies; Acipenserinae, including the genera ''Acipenser'' and ''Huso'', and Scaphirhynchinae, including the genera ''Scaphirhynchus'' and ''Pseudoscaphirhynchus''.<ref name="fishbase">{{FishBase order|order=Acipenseriformes|year=2016|month=12}}</ref> Under a phylogeny that exclusively incorporates morphological data, sturgeons appear to comprise two groups that diverged during the Cretaceous: a ''Scaphirhynchus'' lineage, and a ''Acipenser''+''Huso''+''Pseudoscaphirhynchus'' lineage. The latter seemingly appears rather young compared to the age of the group as a whole, with much of its radiation only occurring during the Late Paleogene and Neogene.<ref name=":2" />

However, with the advent of molecular phylogenetics, multiple studies since the 1990s have recovered this arrangement as paraphyletic, instead finding ''A. oxyrhinchus'' and ''A. sturio'' to form the most basal clade among sturgeons, and all other species being in a separate clade, with the various other species of ''Acipenser'', ''Scaphirhynchus'', ''Pseudoscaphirhynchus'', and ''Huso'' to have varying levels of relationship with one another. The morphologically distinct "shovelnose" type sturgeons are deeply nested within the former "''Acipenser''" and "''Huso''" clades. The divergences within the group have also been found to be much deeper, with ''Acipenser sensu stricto'' diverging from the rest of the group well into the Cretaceous. The other lineages were found to have diverged from one another during the Late Cretaceous and Paleogene.<ref>{{Cite journal |last1=Choudhury |first1=Anindo |last2=Dick |first2=Terry A. |date=1998 |title=The historical biogeography of sturgeons (Osteichthyes: Acipenseridae): a synthesis of phylogenetics, palaeontology and palaeogeography |url=https://onlinelibrary.wiley.com/doi/abs/10.1046/j.1365-2699.1998.2540623.x |journal=Journal of Biogeography |language=en |volume=25 |issue=4 |pages=623–640 |doi=10.1046/j.1365-2699.1998.2540623.x |bibcode=1998JBiog..25..623C |issn=1365-2699|url-access=subscription }}</ref><ref name=":5" /><ref name=":0">{{Cite journal|last1=Luo|first1=Dehuai|last2=Li|first2=Yanping|last3=Zhao|first3=Qingyuan|last4=Zhao|first4=Lianpeng|last5=Ludwig|first5=Arne|last6=Peng|first6=Zuogang|date=2019-01-10|title=Highly Resolved Phylogenetic Relationships within Order Acipenseriformes According to Novel Nuclear Markers|journal=Genes|volume=10|issue=1|page=38|doi=10.3390/genes10010038|issn=2073-4425|pmc=6356338|pmid=30634684|doi-access=free}}</ref><ref name=":1">{{Cite journal|last1=Shen|first1=Yanjun|last2=Yang|first2=Na|last3=Liu|first3=Zhihao|last4=Chen|first4=Qiliang|last5=Li|first5=Yingwen|date=2020-09-01|title=Phylogenetic perspective on the relationships and evolutionary history of the Acipenseriformes|journal=Genomics|language=en|volume=112|issue=5|pages=3511–3517|doi=10.1016/j.ygeno.2020.02.017|pmid=32105795|s2cid=211555175|issn=0888-7543|doi-access=free}}</ref>

The exact placement of ''Scaphirhynchus'' varies depending on the study and the methods used, with some placing it within the second-most basal clade comprising primarily Pacific species, whereas others place it in its own clade that is more derived than the secondmost basal clade but less derived than the most derived Atlantic and Central Asian clade. No studies have yet delineated a relationship between it and ''Pseudoscaphirhynchus''. In addition, the exact relationships of the members of the most derived, primarily Atlantic clade vary, although most analyses at least find all the species in it to form a monophyletic clade. The placement of ''A. sinensis'' also varies by the study, with some placing it as the only Pacific member of the otherwise Atlantic-based most-derived clade, whereas others place it with the rest of the Pacific sturgeons as a sister to ''A. dabryanus''.<ref name=":0" /><ref name=":1" />

Brownstein & Near (2025) used DNA sequencing and morphological data to establish 5 monophyletic genera for Acipenseridae and mostly resolve the longstanding confusion over clade names. The 5 clades found were ''Acipenser sensu stricto'', ''Scaphirhynchus'', ''Pseudoscaphirhynchus'', ''Huso'', and the revived genus ''Sinosturio'', as well as moving species out of ''Acipenser'' and into the latter two genera (including the kaluga, now ''Sinosturio dauricus'').<ref name="CofFF" /><ref name=":2" />

The following taxonomy is based on Brownstein & Near, 2025:<ref name=":2" />

{{Clade|{{clade |label1=''Acipenser'' |1={{clade |1=''A. sturio'' 90 px |2={{clade |1=''A. oxyrinchus'' 90px |2=''A. desotoi'' }} }} |2={{clade |label1=''Scaphirhynchus'' |1={{clade |1=''S. platorhynchus'' 90 px |2={{clade |1=''S. suttkusi'' 90 px |2=''S. albus'' 90 px }} }} |2={{clade |1={{clade |label1=''Sinosturio'' |1={{clade |1={{clade |1={{clade |1=''S. dabryanus'' 90 px |2=''S. sinensis'' }} |2={{clade |1=''S. schrenckii'' |2=''S. transmontanus'' 90 px }} }} |2={{clade |1={{clade |1=''S. dauricus'' |2={{clade |1=''S. medirostris'' 90 px |2=''S. mikadoi'' }} }} }} }} }}

|2={{clade |label1=''Pseudoscaphirhynchus'' |1={{clade |1=''P. fedtschenkoi'' (likely extinct) 90 px |2={{clade |1=''P. hermanni'' |2=''P. kaufmanni'' }} }} |label2=''Huso'' |2 = {{clade |1=''H. fulvescens'' 90 px |2={{clade |1={{clade |1=''H. huso'' 90 px |2={{clade |1=''H. stellatus'' 90 px |2={{clade |1=''H. ruthenus'' 90 px |2=''H. nudiventris'' 90 px }} }} }} |2={{clade |1=''H. brevirostrum'' 90 px |2={{clade |1=''H. baerii'' |2={{clade |1=''H. persicus'' |2={{clade |1=''H. gueldenstaedtii'' 90 px |2={{clade |1=''H. colchicus'' |2=''H. naccarii'' }} }} }} }} }} }} }} }} }} }} }} }}

=== Species === The family contains 27 recent species in 5 genera, as well as a number of fossil species and genera.

The following classification is based on ''Eschmeyer's Catalog of Fishes'' (2025):<ref name="CofFF" /><ref name=":2" /> [[File:Huge sturgeon in the Gulf of St. Lawrence ecosystem - panoramio.jpg|thumb|The Atlantic sturgeon (''A. oxyrhynchus'') is one of the most basal sturgeon species]] [[File:Scaphirhynchus platorynchus 6.14.2014c.jpg|thumb|Shovelnose sturgeons (''Scaphirhynchus platorynchus'') are morphologically atypical members of the group]] [[File:Білуга (Huso huso).jpg|thumb|The beluga sturgeon (''Huso huso'') is one of the largest sturgeon species]] [[File:Pseudoscaphirhynchus fedtschenkoi.jpg|thumb|The Syr Darya sturgeon (''Pseudoscaphirhynchus fedtschenkoi'') is likely extinct]] Family '''Acipenseridae''' * Genus ''Acipenser'' Linnaeus, 1758 (native to eastern North America and western Europe) ** ''Acipenser desotoi'' Vladykov, 1955 (Gulf sturgeon) ** ''Acipenser oxyrinchus'' Mitchill, 1815 (Atlantic sturgeon) ** ''Acipenser sturio'' Linnaeus, 1758 (European sea sturgeon) * Genus ''Scaphirhynchus'' Heckel, 1835 (native to central North America) ** ''Scaphirhynchus albus'' (Forbes & R. E. Richardson, 1905) (pallid sturgeon) ** ''Scaphirhynchus platorynchus'' (Rafinesque, 1820) (shovelnose sturgeon) ** ''Scaphirhynchus suttkusi'' J. D. Williams & Clemmer, 1991 (Alabama sturgeon) *Genus ''Sinosturio'' Jaekel ''in'' Weigelt, 1929 (native to East Asia and western North America) **''Sinosturio'' ''dabryanus'' (A. H. A. Duméril, 1869) (Yangtze sturgeon) **''Sinosturio dauricus'' (Georgi, 1775) (kaluga) ** ''Sinosturio medirostris'' (Ayres, 1854) (green sturgeon) ** ''Sinosturio mikadoi'' (Hilgendorf, 1892) (Sakhalin sturgeon) ** ''Sinosturio schrenckii'' (J. F. Brandt, 1869) (Amur sturgeon) ** ''Sinosturio sinensis'' (J. E. Gray, 1835) (Chinese sturgeon) ** ''Sinosturio transmontanus'' (J. Richardson, 1836) (white sturgeon) * Genus ''Huso'' J. F. Brandt & Ratzeburg, 1833 (native to eastern Europe, west Asia, and eastern North America) ** ''Huso baerii'' (J. F. Brandt, 1869) (Siberian sturgeon) *** ''Huso baerii baicalensis'' (A. M. Nikolskii, 1896) (Baikal sturgeon) *** ''Huso'' ''baerii stenorrhynchus'' (A. M. Nikolskii, 1896) ** ''Huso brevirostrum'' (Lesueur, 1818) (shortnose sturgeon) ** ''Huso colchicus'' (Marty, 1940) (Caucasian sturgeon) ** ''Huso fulvescens'' (Rafinesque, 1817) (lake sturgeon) ** ''Huso gueldenstaedtii'' (J. F. Brandt & Ratzeburg, 1833) (Russian sturgeon) ** ''Huso huso'' (Linnaeus, 1758) (beluga) ** ''Huso naccarii'' (Bonaparte, 1836) (Adriatic sturgeon) ** ''Huso nudiventris'' (Lovetsky, 1828) (fringebarbel sturgeon) ** ''Huso persicus'' (Borodin, 1897) (Persian sturgeon) ** ''Huso ruthenus'' (Linnaeus, 1758) (sterlet) ** ''Huso stellatus'' (Pallas, 1771) (starry sturgeon) * Genus ''Pseudoscaphirhynchus'' Nikolskii, 1900 (native to Central Asia) ** ''Pseudoscaphirhynchus fedtschenkoi'' (Kessler, 1872) (Syr Darya sturgeon) ** ''Pseudoscaphirhynchus hermanni'' (Kessler, 1877) (dwarf sturgeon) ** ''Pseudoscaphirhynchus kaufmanni'' (Kessler, 1877) (Amu Darya sturgeon) <gallery class="center"> File:Young lake sturgeon.jpg|A young lake sturgeon (''Huso fulvescens'') File:Hausen (Huso huso L.)editDOB.JPG|Great sturgeon or beluga (''Huso huso'') feeding on another fish File:Pallid sturgeon activity with syphoning.webmhd.webm|Pallid sturgeon (''Scaphirhynchus albus'') showing siphoning feeding behaviour File:Beluga sturgeon in aquarium.webm|Beluga sturgeon in an aquarium. </gallery>

==== Fossil taxa ==== [[File:Acipenser gigantissimus.jpg|thumb|Illustration of the dubious fossil species "''Acipenser''" ''gigantissimus'' from the Late Cretaceous (Maastrichtian) of Russia]] Fossil sturgeons are known from the mid-late Cretaceous onwards. The earliest known sturgeon fossil is of an indeterminate partial skull from the Cenomanian-aged Dunvegan Formation of Alberta, Canada.<ref name=":4" /> It was previously assumed that from ''Asiacipenser kotelnikovi'' Nessov, 1990 from the Late Jurassic of Kazakhstan was the earliest sturgeon, but these remains are non-diagnostic and it is unlikely that it represents a member of the family.<ref name=":6">{{Cite journal |last1=Grande |first1=Lance |last2=Hilton |first2=Eric J. |date=2006 |title=An Exquisitely Preserved Skeleton Representing a Primitive Sturgeon from the Upper Cretaceous Judith River Formation of Montana (Acipenseriformes: Acipenseridae: N. gen. and sp.) |url=https://www.jstor.org/stable/4095815 |journal=Memoir (The Paleontological Society) |volume=65 |pages=1–39 |jstor=4095815 |issn=0078-8597}}</ref> They become particularly diverse during the Late Cretaceous of North America, where multiple different genera are known.

The following species are known:<ref name=":6" /> * Genus "''Acipenser''" Linnaeus, 1758 (''Acipenser sensu lato'') ** †''"Acipenser" albertensis'' Lambe, 1902 (Late Cretaceous of Alberta, Canada) ** †''"''''Acipenser"'' ''anisinferos'' Hilton & Grande, 2023 (Late Cretaceous of North Dakota, USA)<ref name=":7">{{Cite journal |last1=Hilton |first1=Eric J. |last2=Grande |first2=Lance |date=2023 |title=Late Cretaceous sturgeons (Acipenseridae) from North America, with two new species from the Tanis site in the Hell Creek Formation of North Dakota |journal=Journal of Paleontology |language=en |volume=97 |issue=1 |pages=189–217 |doi=10.1017/jpa.2022.81 |bibcode=2023JPal...97..189H |issn=0022-3360|doi-access=free }}</ref> ** †''"Acipenser" chilini'' Nessov, 1983 (Early Paleocene of Kazakhstan) ** ?†''"Acipenser" cretaceous'' Daimeries, 1892 (Late Cretaceous of Belgium; potentially a teleost) ** †''"Acipenser" eruciferus'' Cope, 1876 (Late Cretaceous of Montana, USA) ** †''"Acipenser" gigantissimus'' Nessov, 1997 (Late Cretaceous of Saratov, Russia)<ref>{{Cite journal |last1=Ye.V |first1=Popov |last2=A.a |first2=Yarkov |date=2001 |title=A NEW GIANT SPECIES OF EDAPHODON (HOLOCEPHALI: EDAPHODONTIDAE) FROM THE BERYOZOVAYA BEDS (LOWER PALEOCENE) OF THE VOLGOGRAD VOLGA REGION |url=https://repository.geologyscience.ru/handle/123456789/25322 |journal=Paleontological Journal |volume=35 |issue=2 |issn=0031-0301}}</ref> ** †''"Acipenser" lemoinei'' (Priem, 1901) (Early Eocene of France) ** ?†''"Acipenser" molassicus'' Probst, 1882 (Miocene of Germany; potentially a chondrichthyan) ** †''"Acipenser" ornatus'' Leidy, 1873 (Miocene of Virginia, USA) ** †''"Acipenser" parisiensis'' Priem, 1908 (Early Oligocene of France) ** †''"Acipenser" praeparatorum'' Hilton & Grande, 2023 (Late Cretaceous of North Dakota, USA)<ref name=":7" /> ** †''"Acipenser" toliapicus'' Agassiz 1844 ''ex'' Woodward 1889 (Early Eocene of England) ** ?†''"Acipenser" tuberculosus'' Probst 1882 (Miocene of Germany; potentially a chondrichthyan) ** †''"Acipenser" zhylgensis'' Nessov, 1983 (Early Paleocene of Kazakhstan) *Genus †''Anchiacipenser'' Sato, Murray, Vernygora & Currie, 2018<ref>{{Cite journal |last1=Sato |first1=Hiroki |last2=Murray |first2=Alison M. |last3=Vernygora |first3=Oksana |last4=Currie |first4=Philip J. |date=2018-07-04 |title=A rare, articulated sturgeon (Chondrostei: Acipenseriformes) from the Upper Cretaceous of Dinosaur Provincial Park, Alberta, Canada |journal=Journal of Vertebrate Paleontology |volume=38 |issue=4 |pages=(1)–(15) |doi=10.1080/02724634.2018.1488137 |bibcode=2018JVPal..3888137S |issn=0272-4634}}</ref> **†''Anchiacipenser'' ''acanthaspis'' Sato, Murray, Vernygora & Currie, 2018 (Late Cretaceous of Alberta, Canada & Montana, USA) *Genus †''Boreiosturion'' Murray, Nelson & Brinkman, 2023<ref name=":8">{{Cite journal |last1=Murray |first1=Alison M. |last2=Nelson |first2=Luke E. |last3=Brinkman |first3=Donald B. |date=2023-01-02 |title=A new sturgeon from the Upper Cretaceous Horseshoe Canyon Formation in central Alberta, Canada |journal=Journal of Vertebrate Paleontology |volume=43 |issue=1 |article-number=e2232846 |doi=10.1080/02724634.2023.2232846 |bibcode=2023JVPal..43E2846M |issn=0272-4634}}</ref> **†''Boreiosturion labyrinthicus'' Murray, Nelson & Brinkman, 2023 (Late Cretaceous of Alberta, Canada)<ref name=":8" /> *Genus †''Engdahlichthys'' Murray, Brinkman, DeMar & Wilson, 2020 **†''Engdahlichthys milviaegis'' Murray, Brinkman, DeMar & Wilson, 2020 (Early Paleocene of Montana, USA)<ref name=":3" /> *Genus †''Protoscaphirhynchus'' Wilimovsky, 1956 **†''Protoscaphirhynchus squamosus'' Wilimovsky, 1956 (Late Cretaceous of Montana, USA) *Subfamily †Priscosturioninae Grande & Hilton, 2009 **Genus †''Priscosturion'' Grande & Hilton, 2009 (=''Psammorhynchus'' Grande & Hilton, 2006)<ref name=":6" /> ***†''Priscosturion longipinnis'' (Grande & Hilton, 2006) (Late Cretaceous of Alberta, Canada) Most fossil species placed in "''Acipenser''" are thought to be ''nomina dubia'', being based on fragmentary remains that do not display diagnostic traits.<ref name=":6" /> The exceptions are ''"A.''" ''praeparatorum'' and ''"A.''" ''anisinferos'' from the Hell Creek Formation, which are known from well-preserved remains.<ref name=":7" /> ''A. praeparotorum'' may potentially represent a basal member of the ''Huso''-''Pseudoscaphirhynchus'' lineage.<ref name=":2" />

== Range and habitat ==

[[File:Pantikapaion Tetrachalkon (rev).jpg|thumb|Sturgeon depicted on an ancient Greek Tetrachalkon (bronze coin) from Panticapaeum on the Crimean peninsula (Black Sea), 310–304 B.C.]] Sturgeon range from subtropical to subarctic waters in North America and Eurasia. In North America, they range along the Atlantic Coast from the Gulf of Mexico to Newfoundland, including the Great Lakes and the St. Lawrence, Missouri, and Mississippi Rivers, as well as along the West Coast in major rivers from California and Idaho to British Columbia. They occur along the European Atlantic coast, including the Mediterranean basin, especially in the Adriatic Sea and the rivers of North Italy;<ref>{{Cite web|title=LIFE 04NAT/IT/000126 "Conservation and Breeding of Italian Cobice Endemic Sturgeon"|url=http://ec.europa.eu/environment/life/project/Projects/index.cfm?fuseaction=home.showFile&rep=file&fil=LIFE04_NAT_IT_000126_LAYMAN_IT.pdf}}</ref> in the rivers that flow into the Black, Azov, and Caspian Seas (Danube, Dnepr, Volga, Ural and Don); the north-flowing rivers of Russia that feed the Arctic Ocean (Ob, Yenisei, Lena, Kolyma); in the rivers of Central Asia (Amu Darya and Syr Darya) and Lake Baikal. In the Pacific Ocean, they are found in the Amur River along the Russian-Chinese border, on Sakhalin Island, and some rivers in northeast China.<ref name="Berg" /><ref name="fishbase" />

Throughout this extensive range, almost all species are highly threatened or vulnerable to extinction due to a combination of habitat destruction, overfishing, and pollution.<ref name="fishbase" />

No species is known to naturally occur south of the equator, though attempts at sturgeon aquaculture are being made in Uruguay, South Africa, and other places.<ref>{{cite journal|last1=Burtzev|first1=LA.|year=1999|title=The History of Global Sturgeon Aquaculture|journal=Journal of Applied Ichthyology|volume=15|issue=4–5|page=325|doi=10.1111/j.1439-0426.1999.tb00336.x|doi-access=free|bibcode=1999JApIc..15..325B }}</ref>

Most species are at least partially anadromous, spawning in fresh water and feeding in nutrient-rich, brackish waters of estuaries or undergoing significant migrations along coastlines. However, some species have evolved purely freshwater existences, such as the lake sturgeon (''Acipenser fulvescens'') and the Baikal sturgeon (''A. baerii baicalensis''), or have been forced into them by human or natural impoundment of their native rivers, as in the case of some subpopulations of white sturgeon (''A. transmontanus'') in the Columbia River<ref>{{cite journal|last1=Duke|first1=S.|last2=Anders|first2=P.|last3=Ennis|first3=G.|last4=Hallock|first4=R.|last5=Hammond|first5=J.|last6=Ireland|first6=S.|last7=Laufle|first7=J.|last8=Lauzier|first8=R.|last9=Lockhard|first9=L.|last10=Marotz|first10=B.|last11=Paragamian|first11=V.L.|year=1999|title=Recovery plan for Kootenai River white sturgeon (Acipenser transmontanus)|journal=Journal of Applied Ichthyology|volume=15|issue=4–5|pages=157–163|doi=10.1111/j.1439-0426.1999.tb00226.x|last12=Westerhof|first12=R.|doi-access=free|bibcode=1999JApIc..15..157D }}</ref> and Siberian sturgeon (''A. baerii'') in the Ob basin.<ref>G.I. Ruban, 1999. The Siberian Sturgeon ''Acipenser baerii Brandt'': Structure and Ecology of the Species, Moscow, GEOS. 235 pp (in Russian).</ref>

==Physical characteristics== thumb|upright=1.15|Sturgeon skull – a, Rostrum; b, nasal capsule; c eye-socket; d, foramina for spinal nerves; e, notochord; g, quadrate bone; h, hyomandibular bone; i, mandible; j. basibranchials; k, ribs; l, hyoid bone; I, II, III, IV, V, branchial arches

Sturgeons retain several primitive characteristics from the bony fishes. Along with other members of the subclass Chondrostei, they are unique among bony fishes because their skeletons are almost entirely cartilaginous. To maintain structure, sturgeons are one of few vertebrates to retain a post-embryonic notochord that acts like a soft spine running through the body. Notably, however, the cartilaginous skeleton is not a primitive character, but a derived one; sturgeon ancestors had bony skeletons.<ref name="HelfmanCollette2009"/><ref name="Finch1994">{{cite book|author=Caleb E. Finch|title=Longevity, Senescence, and the Genome|url=https://books.google.com/books?id=_JkMRundeNcC&pg=PA134|date=May 16, 1994|publisher=University of Chicago Press|isbn=978-0-226-24889-9|pages=134–}}</ref><ref name="McPhail2007">{{cite book|author=J. D. McPhail|title=Freshwater Fishes of British Columbia (The)|url=https://archive.org/details/freshwaterfishes00mcph|url-access=registration|date=September 28, 2007|publisher=University of Alberta|isbn=978-0-88864-853-2|pages=[https://archive.org/details/freshwaterfishes00mcph/page/23 23]–}}</ref> They also lack vertebral centra, and are partially covered with five lateral rows of scutes rather than scales.<ref name=VIMS>{{cite web|url=http://www.vims.edu/research/facilities/fishcollection/highlights/atlantic_sturgeon.php|title=Atlantic Sturgeon|publisher=Virginia Institute of Marine Science|date=2009|access-date=August 26, 2016|archive-date=August 9, 2016|archive-url=https://web.archive.org/web/20160809020555/http://www.vims.edu/research/facilities/fishcollection/highlights/atlantic_sturgeon.php}}</ref> They also have four barbels—sensory organs that precede their wide, toothless mouths. They navigate their riverine habitats traveling just off the bottom with their barbels dragging along gravel, or murky substrate. Sturgeon are recognizable for their elongated bodies, flattened rostra, distinctive scutes and barbels, and elongated upper tail lobes. The skeletal support for the paired fins of ray-finned fish is inside the body wall, although the ray-like structures in the webbing of the fins can be seen externally.

Sturgeons are among the largest fish: some beluga (''Huso huso'') in the Caspian Sea reportedly attain over {{convert|5.5|m|ft|0}} and {{convert|2000|kg|lb}}<ref>Frimodt, C., (1995). Multilingual illustrated guide to the world's commercial coldwater fish. Fishing News Books, Osney Mead, Oxford, England. 215 p.</ref> while for kaluga (''H. dauricus'') in the Amur River, similar lengths and over {{convert|1000|kg|lb|abbr=on}} weights have been reported.<ref>Krykhtin, M.L. and V.G. Svirskii (1997). Endemic sturgeons of the Amur River: kaluga, ''Huso dauricus'', and Amur sturgeon, ''Acipenser schrenckii''. Environ. Biol. Fish. 48(1/4):231-239.</ref> They are also among the longest-lived of the fishes, some living well over 100 years and attaining sexual maturity at 20 years or more.<ref name=Berg>Berg, L.S. (1962). Freshwater fishes of the U.S.S.R. and adjacent countries. volume 1, 4th edition. Israel Program for Scientific Translations Ltd., Jerusalem. (Russian version published 1948).</ref> The combination of slow growth and reproductive rates and the extremely high value placed on mature, egg-bearing females make sturgeon particularly vulnerable to overfishing.

Sturgeons are polyploid; some species have four, eight, or 16 sets of chromosomes.<ref name=Anderson>{{cite web |url=http://biology.mcgill.ca/undergra/c465a/biodiver/2000/shortnose-sturgeon/shortnose-sturgeon.htm |title=Shortnose Sturgeon|author=Anderson, Rachel|access-date=August 23, 2007 |year=2004 |publisher=McGill University |archive-url = https://web.archive.org/web/20071024153413/http://biology.mcgill.ca/undergra/c465a/biodiver/2000/shortnose-sturgeon/shortnose-sturgeon.htm  |archive-date = October 24, 2007}}</ref>

==Life cycle== Sturgeons are long-lived, late maturing fishes. Their average lifespan is 50 to 60 years, and their first spawn does not occur until they are around 15 to 20 years old. Sturgeons are broadcast spawners, and do not spawn every year because they require specific conditions. Those requirements may or may not be met every year due to varying environmental conditions, such as the proper photoperiod in spring, clear water with shallow rock or gravel substrate, where the eggs can adhere, and proper water temperature and flow for oxygenation of the eggs. A single female may release 100,000 to 3 million eggs, but not all will be fertilized. The fertilized eggs become sticky and adhere to the bottom substrate upon contact. Eight to 15 days are needed for the embryos to mature into larval fish. During that time, they are dependent on their yolk sacs for nourishment.<ref name="BCME">{{cite web | url=http://www.env.gov.bc.ca/wld/fishhabitats/sturgeon/ | publisher=British Columbia Ministry of Environment, Ecosystems Branch | title=Fish & Habitats– White Sturgeon (Acipenser transmontanus) in British Columbia | access-date=October 28, 2015 | archive-date=May 22, 2018 | archive-url=https://web.archive.org/web/20180522054726/http://www.env.gov.bc.ca/wld/fishhabitats/sturgeon/ }}</ref><ref name=HSBC>{{cite web|url=http://hsbc.frasersturgeon.com/rhspsec/Lesson1/Articles/Article1.pdf | title=Life Cycle of the White Sturgeon| publisher=Fraser River Conservation Society | work=HSBC Fraser River Sturgeon Education Program | access-date=October 28, 2015}}</ref> River currents carry the larvae downstream into backwater areas, such as oxbows and sloughs, where the free-swimming fry spend their first year feeding on insect larvae and crustacea. During their first year of growth, they reach {{convert|18|to|20|cm|in|frac=2|abbr=on}} in length and migrate back into the swift-flowing currents in the main stem river.<ref name="govinfo 1976">{{cite web | title=Investigations of anadromous fishes of the Neuse River, North Carolina | website=govinfo | date=May 1, 1976 | url=https://www.govinfo.gov/content/pkg/CZIC-ql628-n8-h3-1980/html/CZIC-ql628-n8-h3-1980.htm | access-date=April 22, 2019}}</ref>

==Behavior== thumb|right|The underside and mouth of a sturgeon Sturgeons are primarily benthic feeders, with a diet of shellfish, crustaceans, and small fish. Exceptionally, the beluga sturgeon, the kaluga sturgeon, the white sturgeon and the pallid sturgeon all feed primarily on other fish as adults. They feed by extending their siphon-like mouths to suck food from the benthos. Having no teeth, they are unable to seize prey, though larger individuals and more predatory species can swallow very large prey items, including whole salmon.<ref>[http://www.npafc.org/new/publications/Technical%20Report/TR4/page%2067-69(Zolotukhin).pdf Sergei F. Zolotukhin and Nina F. Kaplanova. (2007) Injuries of Salmon in the Amur River and its Estuary as an Index of the Adult Fish Mortality in the Period of Sea Migrations. NPAFC Technical Report No. 4.]</ref> Sturgeons feed non-visually. They are believed to use a combination of sensors, including olfactory, tactile, and chemosensory cues detected by the four barbels, and electroreception using their ampullae of Lorenzini.<ref name="Zhang" />

The sturgeons' electroreceptors are located on the head and are sensitive to weak electric fields generated by other animals or geoelectric sources.<ref name="Herzog">{{cite journal |author=Herzog, H. |year=2011 |title=Response properties of the electrosensory neurons in hindbrain of the white sturgeon, Acipenser transmontanus |journal=Neuroscience Bulletin |volume=27 |issue=6 |pages=422–429 |doi=10.1007/s12264-011-1635-y |pmid=22108819 |pmc=5560385}}</ref> The electroreceptors are thought to be used in various behaviors such as feeding, mating and migration.<ref name="Zhang">{{cite journal |author=Zhang, X. |author2=Song, J. |author3=Fan, C. |author4=Guo, H.|author5=Wang, X. |author6=Bleckmann, H. |year=2012 |title=Use of electrosense in the feeding behavior of sturgeons |journal=Integrative Zoology|volume=7 |issue=1 |pages=74–82 |doi=10.1111/j.1749-4877.2011.00272.x |pmid=22405450}}</ref>

Many sturgeons leap completely out of the water,<ref name="Video">{{Cite web|url=https://www.youtube.com/watch?v=jSfo2cwXDo4| archive-url=https://ghostarchive.org/varchive/youtube/20211103/jSfo2cwXDo4| archive-date=2021-11-03 | url-status=live|title=The Gulf Sturgeon|date=October 7, 2011|via=YouTube}}{{cbignore}}</ref> usually making a loud splash which can be heard half a mile away on the surface and probably farther under water. Why they do this is not known, but suggested functions include group communication to maintain group cohesion, catching airborne prey, courtship display, or to help shed eggs during spawning. Other plausible explanations include escape from predators, shedding parasites, or to gulp or expel air.<ref name="Sulak">{{cite journal |last1=Sulak |first1=K. J. |last2=Edwards |first2=R. E. |last3=Hill |first3=G. W. |last4=Randall |first4=M. T. |year=2002 |title=Why do sturgeons jump? Insights from acoustic investigations of the Gulf sturgeon in the Suwannee River, Florida, USA |journal=Journal of Applied Ichthyology |volume=18 |issue=4–6 |pages=617–620 |doi=10.1046/j.1439-0426.2002.00401.x|doi-access=free |bibcode=2002JApIc..18..617S }}</ref> Another explanation is that it "simply feels good".<ref name="Waldman" /> There have been some incidents of leaping sturgeon landing in boats and causing injuries to humans;<ref name="injuries">{{cite journal |author=Wilson, J. P. |author2=Burgess, G. |author3=Winfield, R. D. |author4=Lottenberg, L. |name-list-style=amp|year=2009 |title=Sturgeons versus surgeons: leaping fish injuries at a level I trauma center|journal=The American Surgeon|volume=75 |issue=3 |pages=220–222 |doi=10.1177/000313480907500306 |pmid=19350856 |s2cid=33997325 |doi-access=free }}</ref> in 2015, a 5-year-old girl was fatally injured after a sturgeon leapt from the Suwannee River and struck her.<ref name="Fatality">{{cite news |title=Leaping sturgeon kills five-year-old girl boating in Florida |work=Reuters |year=2015 |url=https://www.reuters.com/article/us-usa-sturgeon-florida/leaping-sturgeon-kills-five-year-old-girl-boating-in-florida-idUSKCN0PE0UY20150704}}</ref> {{Quote box|width=40em|align=center|quote=In 1731, an observer of leaping sturgeon wrote: {{Cquote|''...in May, June and July, the rivers abound with them, at which time it is surprising, though very common to see such large fish elated in the air, by their leaping some yards out of the water; this they do in an erect posture, and fall on their sides, which repeated percussions are loudly heard some miles distance....''<ref name="Waldman">{{cite web |title=Outdoors: The lofty mystery of why sturgeon leap |year=2001 |author=Waldman, J. |work=The New York Times |url=https://www.nytimes.com/2001/10/21/sports/outdoors-the-lofty-mystery-of-why-sturgeon-leap.html}}</ref>}}}}

==Interactions with humans== [[File:Caviar and spoon.jpg|thumb|upright=1.0|The demand for caviar has driven several species of sturgeon toward extinction.]]

===Caviar=== {{Further|Caviar}} thumb|Beluga sturgeon at a caviar farm in South Korea. [[File:SturgeonTurkmarket.jpg|thumb|225px|Woman selling sturgeon at a market in Türkmenbaşy, Turkmenistan]] Globally, sturgeon fisheries are of great value, primarily as a source for caviar, but also for flesh.<ref name="Profita 2015">{{cite web | last=Profita | first=Cassandra | title=World's Appetite For Caviar Sends Poachers After Columbia River Sturgeon | website=OPB | date=May 16, 2015 | url=https://www.opb.org/news/series/wildlife-detectives/worlds-appetite-for-caviar-sends-poachers-after-columbia-river-sturgeon/ | access-date=April 19, 2019 | archive-date=April 17, 2019 | archive-url=https://web.archive.org/web/20190417191838/https://www.opb.org/news/series/wildlife-detectives/worlds-appetite-for-caviar-sends-poachers-after-columbia-river-sturgeon/ }}</ref> Several species of sturgeon are harvested for their roe which is processed into caviar—a delicacy, and the reason why caviar-producing sturgeons are among the most valuable and endangered of all wildlife resources.<ref name="CITES">{{cite web | url=https://www.cites.org/eng/prog/sturgeon.php | title=Sturgeons | publisher=Convention on International Trade in Endangered Species of Wild Fauna and Flora | access-date=April 17, 2019}}</ref>

During the 19th century, the US was the global leader in caviar production, having cornered 90% of the world's caviar trade.<ref name=Mizerek>{{cite report|url=http://seafood.ocean.org/wp-content/uploads/2016/10/Sturgeon-White-Shovlnose-American-Paddlefish-US.pdf|title=White sturgeon, Shovelnose sturgeon, American Paddlefish|work=Monterray Bay Aquarium Seafood Watch|last=Mizerek|first=Toni|date=December 12, 2013|access-date=April 17, 2019}}</ref> Atlantic sturgeon once thrived along the east coast from Canada down to Florida. They were in such abundance in the Hudson River that they were humorously called "Albany beef" and sturgeon eggs were given away at local bars as an accompaniment to 5¢ beer.<ref name="Kleiman 1990">{{cite web | last=Kleiman | first=Dena | title=Caviar: Black Gold In America | website=The New York Times | date=May 9, 1990 | url=https://www.nytimes.com/1990/05/09/garden/caviar-black-gold-in-america.html | access-date=April 17, 2019}}</ref> White sturgeon populations along the US west coast declined simultaneously under the pressure of commercial fishing and human encroachment. Within the course of a century, the once abundant sturgeon fisheries in the US and Canada had drastically declined, and in some areas had been extirpated under the pressure of commercial overharvesting, pollution, human encroachment, habitat loss, and the damming of rivers that blocked their ancestral migration to spawning grounds.<ref name=Mizerek/><ref name=Fox>{{cite journal|url=https://www.st.nmfs.noaa.gov/spo/FishBull/1163/fox.pdf|title=Seasonal occurrence of Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus) in the St. Johns River, Florida|journal=Fishery Bulletin|last1=Fox|first1=Adam G.|last2=Stowe|first2=Edward S.| last3=Dunton |first3=Keith|last4=Peterson|first4=Douglas L.|volume=116 |pages=219–227 |date=2018 |issue=3|doi=10.7755/fb.116.3.1|doi-access=free}}</ref>

By the turn of the century, commercial production of sturgeon caviar in the US and Canada had come to an end. Regulatory protections and conservation efforts were put in place by state and federal resource agencies in the US and Canada, such as the 1998 US federal moratorium that closed all commercial fishing for Atlantic sturgeon.<ref name=Fox/> It was during the 20th century that Russia grew to become the global leader as the largest producer and exporter of caviar.<ref name=Mizerek/> As with the decline in sturgeon populations in the US and Canada, the same occurred with sturgeon populations in the Caspian Sea.<ref name="CITES 2010">{{cite web | title=Caspian States agree on quotas for wild caviar | website=CITES | date=July 23, 2010 | url=https://www.cites.org/eng/news/pr/2010/20100723_caviar.shtml | access-date=April 17, 2019}}</ref>

Beginning with the 1979 US embargo on Iran, poaching and smuggling sturgeon caviar was big business but an illegal and dangerous one.<ref name="Washington Post 1979">{{Cite news |last=Branigin |first=William |date=June 14, 1979 |title=And Poaching 'Pearls From the Caspian' |newspaper=Washington Post |url=https://www.washingtonpost.com/archive/lifestyle/1979/06/14/and-poaching-pearls-from-the-caspian/c1c183d9-3aca-47b5-adab-3a91f9efa0e0/ |access-date=April 17, 2019}}</ref> Officers with the Washington Department of Fish and Wildlife (WDFW) busted a poaching ring that was based in Vancouver, Washington. The poachers had harvested 1.65 tons of caviar from nearly 2,000 white sturgeon that were poached from the Columbia River. The caviar was estimated to be worth around $2 million. WDFW busted another ring in 2003, and conducted an undercover sting operation in 2006–2007 that resulted in 17 successful attempts out of a total of 19.<ref name="NPR.org 2015">{{cite web | title=As Caviar Prices Skyrocket, Sturgeon Poachers Invade Pacific Northwest | website=NPR | date=June 1, 2015 | url=https://www.npr.org/sections/thesalt/2015/06/01/410593098/as-caviar-prices-skyrocket-sturgeon-poachers-invade-pacific-northwest | access-date=April 17, 2019}}</ref>

In response to concerns over the future of sturgeons and associated commercial products, international trade for all species of sturgeons has been regulated under CITES since 1998.<ref name="CITES"/>

===Conservation===

Sturgeons are threatened by the negative impacts of overfishing, poaching, habitat destruction, and the construction of dams that have altered or blocked their annual migration to ancestral spawning grounds.<ref>{{cite web |url= https://www.wwfadria.org/?7158241/IUCN---sturgeons-slipping-towards-extinction |title= Worrying results of the IUCN assessment: sturgeons slipping towards extinction |author=  |publisher= WWF (World Wide Fund for Nature, former World Wildlife Fund) |access-date=February 19, 2026 |url-status=live |archive-url= https://web.archive.org/web/20260219085156/https://www.wwfadria.org/?7158241/IUCN---sturgeons-slipping-towards-extinction |archive-date= February 19, 2026 }}</ref><ref name="PISCES">{{cite web | title=Acipenser transmontanus | website=PISCES | url=https://pisces.ucdavis.edu/content/acipenser-transmontanus | access-date=April 19, 2019 | archive-date=March 16, 2022 | archive-url=https://web.archive.org/web/20220316013340/https://pisces.ucdavis.edu/content/acipenser-transmontanus }}</ref><ref>Clover, Charles. 2004. ''The End of the Line: How overfishing is changing the world and what we eat''. Ebury Press, London. {{ISBN|0-09-189780-7}}</ref> Some species of sturgeon are extinct, and several are on the verge of extinction, including the Chinese sturgeon,<ref name="Griggs 2014">{{cite web | last=Griggs | first=Mary Beth | title=Chinese Sturgeon Is on the Brink of Extinction After 140 Million Years | website=Smithsonian | date=September 16, 2014 | url=https://www.smithsonianmag.com/smart-news/chinese-sturgeon-brink-extinction-after-140-million-years-180952715/ | access-date=April 19, 2019}}</ref> the highly prized beluga sturgeon,<ref name="ScienceDaily 2019">{{cite web | title=Beluga Sturgeon Threatened With Extinction, Yet Caviar Quotas Remain Unchanged -- ScienceDaily | website=ScienceDaily | date=April 19, 2019 | url=https://www.sciencedaily.com/releases/2008/03/080304093748.htm | access-date=April 19, 2019}}</ref> and the Alabama sturgeon.<ref name="Program 2010">{{cite web | last=Program | first=Pallid Sturgeon Recovery | title=Related Species | website=Pallid Sturgeon Recovery Program | date=December 1, 2009 | url=http://www.pallidsturgeon.org/about/related-species/ | access-date=April 19, 2019}}</ref> Many species are classified as threatened or endangered, with noticeable declines in sturgeon populations as the demand for caviar increases. IUCN data indicates that over 85% of sturgeon species are at risk of extinction, making them more critically endangered than any other group of animal species.<ref name=iucn>{{cite web |url= https://www.iucn.org/content/sturgeon-more-critically-endangered-any-other-group-species|title=Sturgeon more critically endangered than any other group of species |date= March 18, 2010 |publisher= IUCN, International Union for Conservation of Nature |access-date=April 19, 2019}}</ref><ref>{{Cite web |url=http://cmsdata.iucn.org/downloads/species__status_and_population_trend_of_sturgeon_on_the_red_list.pdf |title=Species, status and population trend of Sturgeon on the IUCN Red List of Threatened Species (pdf) |access-date=December 6, 2010 |archive-date=October 4, 2011 |archive-url=https://web.archive.org/web/20111004231545/http://cmsdata.iucn.org/downloads/species__status_and_population_trend_of_sturgeon_on_the_red_list.pdf }}</ref>

In addition to global restocking efforts, the monitoring of populations and habitat, and various other conservation efforts by national and state resource agencies as applicable to their respective countries, several conservation organizations have been formed to assist in the preservation of sturgeons around the world. On a global scale, one such organization is the World Sturgeon Conservation Society (WSCS) whose primary objectives include fostering the "conservation of sturgeon species and restoration of sturgeon stocks world-wide", and supporting the "information exchange among all persons interested in sturgeons."<ref name="WSCS">{{cite web | last=Area | first=Jam | title=Who we are | website=W.S.C.S., World Sturgeon Conservation Society | url=http://www.wscs.info/about/who-we-are.aspx | access-date=April 17, 2019}}</ref> The North American Sturgeon and Paddlefish Society (NASPS)<ref name="Area">{{cite web | last=Area | first=Jam | title=Who We Are | website=North American Sturgeon and Paddlefish Society | url=http://www.nasps-sturgeon.org/about/who-we-are.aspx | access-date=April 19, 2019}}</ref> and Gesellschaft zur Rettung des Störs e.V.<ref name="Startseite">{{cite web | title=Gesellschaft zur Rettung des Störs e.V. | website=Startseite | url=http://www.sturgeon.de/ | language=de | access-date=April 19, 2019 | archive-date=April 19, 2019 | archive-url=https://web.archive.org/web/20190419130216/http://www.sturgeon.de/ }}</ref> are WSCS affiliates. WSCS has been instrumental in organizing global conferences where scientists and researchers can exchange information and address the various conservation challenges that threaten the future of sturgeons.<ref name="Area 2012">{{cite web | last=Area | first=Jam | title=Reports on past conferences | website=W.S.C.S., World Sturgeon Conservation Society | date=March 12, 2012 | url=http://www.wscs.info/conferences/reports-on-past-conferences.aspx | access-date=April 19, 2019}}</ref> Conservation efforts at the grass roots level are also instrumental in helping to preserve sturgeon populations, such as Sturgeon For Tomorrow<ref name="Fond du Lac and the Lake Winnebago Region, Wisconsin, Tourism and Conventions in Fond du Lac, WI">{{cite web | title=Sturgeon Spearing | website=Fond du Lac and the Lake Winnebago Region, Wisconsin, Tourism and Conventions in Fond du Lac, WI | url=https://www.fdl.com/sturgeonspearing/ | access-date=April 19, 2019 | archive-date=April 19, 2019 | archive-url=https://web.archive.org/web/20190419130216/https://www.fdl.com/sturgeonspearing/ }}</ref> which was founded in 1977, consists of volunteers and a sturgeon guarding program to monitor known spawning sites. The organization has grown exponentially over the years and has become "the largest citizen advocacy group for sturgeon in the world", and has expanded with affiliate chapters in other states that have sturgeon populations.<ref name=SFT>{{cite web|url=https://dnr.wi.gov/topic/fishing/documents/sturgeon/VignetteSturgeonforTomorrow2016.pdf|title=Sturgeon Vignette – Sturgeon for Tomorrow|publisher=Wisconsin DNR|access-date=April 19, 2019}}</ref><ref name="Card 2012">{{cite web | last=Card | first=James | title=Spearing Sturgeon on Wisconsin's Lake Winnebago | website=The New York Times | date=February 28, 2012 | url=https://www.nytimes.com/2012/02/28/sports/spearing-sturgeon-on-wisconsins-lake-winnebago.html | access-date=April 19, 2019}}</ref> Other projects focus on specific local issues, such as the We Pass project, seeking a solution to the migratory impasse represented by the Iron Gates in the Danube River Basin.<ref>{{cite web |url=https://we-pass.org/ |title=We Pass |date=2020 |website=We Pass |publisher=ICPDR}}</ref> For example, currently all anadromous Danube sturgeon (all species except the predominantly freshwater sterlet) are now classed as Critically Endangered or extirpated from the upper and middle reaches of the Danube River above the dams.<ref>{{cite web |url=http://awsassets.panda.org/downloads/14_2011_conservation_use_of_sturgeon_l_danube_and_black_sea_rogin_norway.pdf |title=Conservation and sustainable use of wild sturgeon populations of the NW Black Sea and Lower Danube River in Romania |last=Rogin |first=Raluca Elena |date=2011 |publisher=Norwegian University of Science and Technology Department of Biology}}</ref>

===Other uses=== [[File:AD 2023 - Temsica Amelberga.jpg|thumb|upright=0.75|St Amalberga riding a sturgeon]] Before 1800, swim bladders of sturgeon (primarily Beluga sturgeon from Russia) were used as a source of isinglass, a form of collagen used historically for the clarification of wine and beer, as a predecessor for gelatin, and to preserve parchments.<ref>{{cite book | last = Davidson | first = Alan | title = Oxford Companion to Food | year = 1999 | isbn = 978-0-19-211579-9 | pages = [https://archive.org/details/oxfordcompaniont00davi_0/page/407 407] | chapter = Isinglass | publisher = Oxford University Press | chapter-url-access = registration | chapter-url = https://archive.org/details/oxfordcompaniont00davi_0/page/407 }}</ref>

The Jewish laws of kashrut, which only permit the consumption of fish with both scales and fins, forbids sturgeon, as they have ganoid scales instead of the permitted ctenoid and cycloid scales. While all Orthodox groups forbid the consumption of sturgeon, some Conservative groups do allow it.<ref>{{cite web|url=http://www.bluethread.com/kashrut/sturgeon.html|title=Sturgeon: A controversial fish.|work=bluethread.com}}</ref> The theological debate over its kosher status can be traced back to such 19th-century reformers as Aron Chorin, though its consumption was already common in European Jewish communities.<ref>{{cite book | last = Lupovich | first = Howard | title = Jews and Judaism in World History | year = 2010 | isbn = 978-0-203-86197-4 | page = 258 | chapter = 7| publisher = Taylor & Francis }}</ref>

Sturgeons were declared to be a royal fish under a statute dating back to 1324 by King Edward II of England. Technically, the British monarchy still owns all sturgeons, whales, and dolphins that inhabit the waters around England and Wales.<ref name="Price 2016">{{cite web | last=Price | first=Rob | title=The incredible powers you didn't know the Queen has | website=The Independent | date=September 26, 2016 | url=http://www.independent.co.uk/news/people/queen-elizabeth-ii-owns-every-dolphin-in-britain-and-doesnt-need-a-driving-license-here-are-the-a7331266.html |archive-url=https://ghostarchive.org/archive/20220525/http://www.independent.co.uk/news/people/queen-elizabeth-ii-owns-every-dolphin-in-britain-and-doesnt-need-a-driving-license-here-are-the-a7331266.html |archive-date=May 25, 2022 |url-access=subscription |url-status=live | access-date=April 19, 2019}}</ref><ref name="BBC News 2004">{{cite web | title=Police inquiry over sturgeon sale | website=BBC News | date=June 3, 2004 | url=http://news.bbc.co.uk/2/hi/uk_news/wales/3773171.stm | access-date=May 17, 2018}}</ref> Under the law of the United Kingdom, any sturgeons captured within the realm are personal property of the monarch.<ref>William Blackstone, Commentaries on the Laws of England, book I, ch. 8 "Of the King's Revenue", ss. X, p. *280</ref>

Similar laws reserving sturgeon for the king were enforced in late medieval Denmark. An archaeological example of sturgeon in a royal context comes from the wreck of the Danish-Norwegian flagship, Gribshunden, which sank in June 1495 while King Hans sailed from Copenhagen to Kalmar, Sweden for a diplomatic summit. Archaeologists recovered from the wreck a cask containing a butchered sturgeon, probably intended for the king's table during feasts in Kalmar.<ref>{{Cite journal |last1=Macheridis |first1=Stella |last2=Hansson |first2=Maria C. |last3=Foley |first3=Brendan P. |date=October 2020 |title=Fish in a barrel: Atlantic sturgeon (Acipenser oxyrinchus) from the Baltic Sea wreck of the royal Danish flagship Gribshunden (1495) |journal=Journal of Archaeological Science: Reports |volume=33 |article-number=102480 |doi=10.1016/j.jasrep.2020.102480 |bibcode=2020JArSR..33j2480M |issn=2352-409X|doi-access=free }}</ref>

In heraldry, a sturgeon is the symbol on the coat of arms for Saint Amalberga of Temse.<ref name=Cornwell>{{cite book|url=https://books.google.com/books?id=J2kX8f3iJfEC&q=sturgeon+is+the+symbol+of+Saint+Amalberga+of+Temse&pg=PA21|title=Saints, Signs, and Symbols: The Symbolic Language of Christian Art|publisher=Church Publishing Inc. |date=July 1, 2009|last=Cromwell|first=James|page=21|access-date=May 15, 2017|isbn=978-0-8192-2765-2}}</ref> {{Clear}}

==Notes== * This article incorporates text from a publication now in the public domain: {{Cite EB1911|wstitle=Sturgeon}}

==References== {{Reflist|30em}}

==External links==

{{Commons category|Acipenseridae}} {{NIE Poster|year=1905}} * [http://www.fishbase.org/identification/specieslist.cfm?famcode=32&areacode= FishBase info on Acipenser] * [http://www.wscs.info/ Official website] of the World Sturgeon Conservation Society * [http://www.earthwave.org/sturgeon_gallery PBS special, video clips and public outreach videos about sturgeon] {{Webarchive|url=https://web.archive.org/web/20200221005447/http://www.earthwave.org/sturgeon_gallery |date=February 21, 2020 }}

{{Chondrostei|state=collapsed}} {{Commercial fish topics}} {{Acipenseriformes}} {{Taxonbar|from=Q181871}} {{Authority control}} {{Good article}}

Category:Sturgeons Category:Articles containing video clips Category:Commercial fish Category:Apex predators Category:Taxa named by Charles Lucien Bonaparte Category:Extant Maastrichtian first appearances