{{Short description|Species of fish}} {{Distinguish|Starlet (disambiguation){{!}}Starlet}} {{Speciesbox | image = Acipenser ruthenus Prague Vltava_1.jpg | image_caption = | status = EN | status_system = IUCN3.1 | status_ref = <ref name="iucn status 19 November 2021">{{cite iucn |author=Gessner, J.|author2=Freyhof, J. |author3=Kottelat, M. |author4=Friedrich, T. |date=2022 |title=''Acipenser ruthenus'' |volume=2022 |article-number= e.T227A135062526|url=https://www.iucnredlist.org/species/227/135062526 |access-date=2 August 2022}}</ref> | status2 = CITES_A2 | status2_system = CITES | status2_ref = <ref>{{Cite web|title=Appendices {{!}} CITES|url=https://cites.org/eng/app/appendices.php|access-date=2022-01-14|website=cites.org}}</ref> | taxon = Huso ruthenus | authority = (Linnaeus, 1758) | synonyms_ref = <ref>{{Cite web|last1=Froese|first1=R.|last2=Pauly|first2=D.|year=2017|title=Acipenseridae |url=http://www.fishbase.se/Summary/FamilySummary.php?ID=32|website=FishBase version (02/2017)|access-date=18 May 2017}}</ref><ref>{{Cite web|title=Acipenseridae |url=http://deeplyfish.com/wp-content/uploads/2017/05/Family-Acipenseridae-PDF.pdf|website=Deeplyfish- fishes of the world|access-date=18 May 2017}}</ref> | synonyms = {{collapsible list|bullets = true|title=<small>List</small> | ''Acipenser pygmaeus'' <small>Pallas 1814 non Reisinger 1830</small> | ?''Acipenser kostera'' <small>Fitzinger 1832</small> | ?''Acipenser koster'' <small>Gmelin 1774 nomen nudum</small> | ''Acipenser marsiglii'' <small>Brandt 1833</small> | ''Acipenser kamensis'' <small>Lovetsky 1834</small> | ''Acipenser gmelini'' <small>Fitzinger 1836</small> | ''Acipenser aleutensis'' <small>Fitzinger 1836</small> | ''Acipenser dubius'' <small>Heckel 1836</small> | ?''Acipenser ruthenus'' var. ''leucotica'' <small>Brandt 1853</small> | ''Acipenser ruthenus'' var. ''grisescens'' <small>Brandt 1853</small> | ''Acipenser'' (''Sterletus'') ''kankreni'' <small>Valenciennes ex Duméril 1870</small> | ''Acipenser'' (''Sterletus'') ''lovetzkyi'' <small>Duméril 1870</small> | ''Sterledus ruthenus'' var. ''sibiricus'' <small>Dybowski 1874</small> | ''Acipenser jeniscensis'' <small>Herzenstein 1895</small> | ''Acipenser ruthenus'' var. ''albinea'' <small>Brusina 1902</small> | ''Acipenser ruthenus'' var. ''birostrata'' <small>Brusina 1902</small> | ''Acipenser ruthenus'' var. ''obtusirostra'' <small>Brusina 1902 non Lovetsky 1834</small> | ''Acipenser ruthenus'' var. ''septemcarinata'' <small>Brusina 1902</small> | ''Acipenser ruthenicus'' <small>Brusina 1902</small> | ''Acipenser sterlet'' <small>Brusina 1902</small> | ''Acipenser sterleta'' <small>Güldenstädt 1772</small> | ''Acipenser ruthenus'' var. ''albus'' <small>Antipa 1909</small> | ''Acipenser ruthenus'' var. ''erytraea'' <small>Antipa 1909</small> | ''Acipenser ruthenus'' var. ''brevirostris'' <small>Antipa 1909</small> | ''Acipenser ruthenus ruzskyi'' <small>Johansen 1946</small> | ''Acipenser ruthenus ruzskyi'' n. ''baschmakovae'' <small>Johansen 1946</small> | ''Acipenser kosterus'' <small>Fitzinger 1832</small> | ''Euacipenser ruthenus'' <small>(Linnaeus 1758)</small> | ''Sterledus ruthenus sibiricus'' <small>Dybowski 1874</small> | ''Sterleta ruthena'' <small>(Linnaeus 1758)</small> | ''Sterletae ruthena'' <small>(Linnaeus 1758)</small> | ''Sterletus ruthenus'' <small>(Linnaeus 1758)</small> }} | range_map = AcipenserRuthenusIUCN2020-1.png | range_map_caption = Range of ''A. ruthenus''{{leftlegend|#008000|Resident|outline=gray}} {{leftlegend|#FF0000|Extinct|outline=gray}} }}
The '''sterlet''' (''Huso ruthenus'')<ref name="CofFF">{{Cof genus|genus=Huso|access-date=28 May 2025}}</ref> is a relatively small species of sturgeon from Eurasia native to large rivers that flow into the Black Sea, Azov Sea, and Caspian Sea, as well as rivers in Siberia as far east as Yenisei. Populations migrating between fresh and salt water (anadromous) have been extirpated.<ref name="iucn status 19 November 2021" /> It is also known as the '''sterlet sturgeon'''.
Due to overfishing (for its flesh, caviar, and isinglass), pollution, and dams, the sterlet has declined throughout its native range and is considered endangered by the IUCN. Restocking projects are ongoing, and it has been introduced to some regions outside its native range, but the latter have generally not become self-sustaining. Today, the majority of the international trade involves sterlets from aquaculture.<ref name="iucn status 19 November 2021" />
== Taxonomy == Prior to 2025, it was placed in the genus ''Acipenser'', but this placement was found to be paraphyletic, and it is more accurately placed in the genus ''Huso''.<ref name="CofFF" /><ref name=":222">{{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>
==Physical appearance== {{Unreferenced section|date=January 2021}} The sterlet may reach 16 kg in weight and 100 to 125 cm in length, rarely exceeding a length of 90 cm. It is quite variable in coloration, but usually has a yellowish ventral side.
It can be distinguished from other European species of sturgeons by the presence of a great number of whitish lateral scutes, fringed barbels, and an elongated and narrow snout, highly variable in length.
==Feeding habits== The sterlet's main source of food is benthic organisms; they commonly feed on crustaceans, worms, and insect larvae.<ref>{{Cite web |title=What Do Sturgeon Fish Eat? |url=https://sciencing.com/do-sturgeon-fish-eat-8662568.html |access-date=2022-04-29 |website=Sciencing |date=22 November 2019 |language=en}}</ref> thumb|300px|left|On exhibition Subaqueous Vltava, Prague
==Life history== thumb| The sterlet commonly reaches the age of 22 to 25 years. Males reach sexual maturity at 3–7 years old and females at 4–12 years old. Spawning occurs from the middle of April to the beginning of June. Females may lay from 15,000 to 44,000 eggs, at water temperatures preferably {{convert|12|–|17|C|F}}.
==As pond fish== Sterlets require relatively large ponds with good water conditions, and may get entangled in plants such as blanketweed. They may require special food such as sterlet sticks, as they are unable to digest the vegetable proteins usually found in commercial fish foods.{{Citation needed|date=February 2021}}
==As food== [[File:Sterlet with satsivi.JPG|thumb|Sterlet with satsivi]] In Russia, it is held in high esteem on account of its excellent flesh, contributing also to the best kinds of caviar and isinglass.{{Citation needed|date=February 2021}}
== History in the Danube== The sterlet (''Acipenser ruthenus'' in Linnaeus' classification) is the last of the five native sturgeon species inhabiting the Middle and Upper Danube River. Its population has dropped significantly, mainly due to the degradation of main habitats, spawning grounds and foraging grounds.<ref>{{Cite journal|last1=Kubala|first1=Maroš|last2=Farský|first2=Martin|last3=Pekárik|first3=Ladislav|date=February 2019|title=Migration patterns of sterlet (Acipenser ruthenus, Linnaeus 1758) in the Middle Danube assessed by 1 year acoustic telemetry study|journal=Journal of Applied Ichthyology|language=en|volume=35|issue=1|pages=54–60|doi=10.1111/jai.13859|bibcode=2019JApIc..35...54K |issn=0175-8659|doi-access=free}}</ref>
==References==
{{Reflist}}
{{Chondrostei}} {{Acipenseriformes|state=expanded}} {{Taxonbar|from=Q211316}} {{Authority control}}
Category:Freshwater fish of Europe Category:Fish of Europe Category:Fish of the Black Sea Category:Fish of Central Asia Category:Fish of Russia Category:Fish described in 1758 Category:Acipenser Category:Animal taxa named by Carl Linnaeus