Editing Chinese paddlefish (section)

==Distribution, habitat and ecology==
[[File:A_specimen_of_Psephurus_gladius,_Museum_of_Hydrobiological_Sciences,_Wuhan_Institute_of_Hydrobiology_(1).jpg|A specimen of ''Psephurus gladius'' exhibited in the Museum of Hydrobiological Sciences of [[Wuhan Institute of Hydrobiology]]|thumb|left]]

The Chinese paddlefish was native to the [[Yangtze River|Yangtze (Chang Jiang) River]] basin and its [[estuary]] at the [[East China Sea]]. Historically it was also recorded in the [[Yellow River]] basin (which is connected to the Yangtze by the [[Grand Canal (China)|Grand Canal]]) and its estuary at the [[Yellow Sea]].<ref name="FAO fact sheet" /><ref name="Xie2018">{{Cite journal |last1=Xie, J.Y. |last2=W.J. Tang |last3=Y.H. Yang |year=2018 |title=Fish assemblage changes over half a century in the Yellow River, China |journal=Ecology and Evolution |volume=8 |issue=8 |pages=4173–4182 |doi=10.1002/ece3.3890 |pmc=5916296 |pmid=29721289|bibcode=2018EcoEv...8.4173X }}<!-- see "Supporting Information" in Xie2018 --></ref><ref name="Li2015">{{Cite book |last=Li, S.Z. |title=Fishes of the Yellow River and Beyond |publisher=The Sueichan Press |year=2015 |isbn=9789578596771 |pages=61–63 |author-link=Li Sizhong (ichthyologist)}}</ref>  It primarily inhabited the large rivers, but sometimes travelled into large lakes.<ref name="iucn" /> Due to their anadromous nature, mature individuals were found in coastal waters of the East China Sea and the Yellow Sea; occasionally [[spring tides]] would bring individuals into the lower reaches of the [[Qiantang]] and [[Yong River (Zhejiang)|Yong]] rivers of [[Zhejiang]] province.<ref name=Chenan1988/>

The species spent part of its life in the lower section of the Yangtze, including the [[brackish]] water of its estuary, but [[Fish migration|migrated]] upriver and into major [[tributaries]] to congregate for [[Spawn (biology)|spawning]], which occurred in spring, from mid-March to early April. One spawning site on the [[Jinsha River]], located at the midpoint of the river, around {{cvt|60|m|ft|sigfig=1}} from the riverbank, was around {{cvt|500|m|ft}} in length, and had a max water depth of {{cvt|10|m|ft}} and rapid water flow, with the bottom sediments in the lower reaches being shingly and in the upper reaches muddy/sandy.<ref name=Chenan1988/> A study on a sample of spawning Chinese paddlefish found that they were all at least 8 years old.<ref name=Wei2002>{{Citation |last1=Wei |first1=Qiwei |last2=Ke |first2=Fu'en |last3=Zhang |first3=Jueming |last4=Zhuang |first4=Ping |last5=Luo |first5=Junde |last6=Zhou |first6=Rueqiong |last7=Yang |first7=Wenhua |year=2002 |title=Biology, fisheries, and conservation of sturgeons and paddlefish in China |work=Sturgeon Biodiversity and Conservation |series=Developments in Environmental Biology of Fishes |publisher=Kluwer Academic Publishers |place=Dordrecht |isbn=0-7923-4517-7 |doi=10.1007/0-306-46854-9_14 |volume=17 |pages=241–255 |url=http://dx.doi.org/10.1007/0-306-46854-9_14 |access-date=2022-07-24 |url-status=live |archive-url=https://web.archive.org/web/20220725001346/https://link.springer.com/chapter/10.1007/0-306-46854-9_14 |archive-date=25 July 2022|url-access=subscription }}</ref> Females likely sexually matured later than males, and probably did not spawn every year, likely every other year or somewhat less frequently, like other acipenseriforms.<ref>{{Cite journal |last=Scarnecchia |first=Dennis L. |date=2023-05-04 |title=The Extinction of the Chinese Paddlefish Psephurus gladius : Transnationalism, Technology Transfer, and Timescape |journal=Reviews in Fisheries Science & Aquaculture |volume=31 |issue=3 |language=en |pages=396–419 |doi=10.1080/23308249.2023.2201636 |issn=2330-8249|doi-access=free |bibcode=2023RvFSA..31..396S }}</ref> The ovaries of the female fish contained over 100,000 eggs, each approximately {{cvt|2.7|mm|in|frac=32|}} across. The developing [[zygote]]s and [[Juvenile fish|fry]] were restricted to the region of the Yangtze basin upstream of [[Luzhou]] in southeastern [[Sichuan]], while yearlings and adults were widely distributed throughout the Yangtze river proper from the lower to upper reaches.<ref name=Chenan1988/>[[File:Chinese paddlefish paddle closeup.jpg|thumb|Closeup of the tip of the rostrum, showing electrorecepting [[Ampullae of Lorenzini|ampullae]] |alt=]]

The fish was largely solitary, and occupied the lower-mid layers of the [[water column]]. Chinese paddlefish were noted for being strong swimmers. Unlike its relative the American paddlefish, which is a [[Planktivore|planktivorous]] filter feeder, the Chinese paddlefish was primarily [[Piscivore|piscivorous]], mainly feeding on small to medium-sized fishes like [[Anchovy|anchovies]] (''[[Coilia]])'', [[Cyprinidae|cyprinids]] (''[[Coreius]], [[Rhinogobio]]'')'','' [[Gobiidae|gobies]] (''[[Gobius]])'' as well as [[Bagridae|bagrid]] catfish and [[Bothidae|bothid]] flounders. Shrimp and crab were also eaten.<ref name=Chenan1988>{{Cite journal |last1=Chenhan |first1=Liu |last2=Yongjun |first2=Zeng |date=1988-05-18 |title=Notes on the Chinese Paddlefish, Psephurus gladius (Martens) |journal=Copeia |volume=1988 |issue=2 |pages=482 |doi=10.2307/1445891 |jstor=1445891}}</ref><ref name="FAO fact sheet" /> The jaws, unlike the American paddlefish but like sturgeons and fossil paddlefish, were capable of [[Jaw protrusion|protrusion]], a form of [[cranial kinesis]] allowing them to move relative to the rest of the skull, with the upper jaw being able to thrust downwards and forwards in order to seize prey.<ref name="Grande1991" /><ref name=Bemis2002>{{cite journal|last1=Bemis |first1=William E. |last2=Findeis |first2=Eric K. |last3=Grande |first3=Lance |editor1-last=Birstein |editor1-first=Vadim J. |editor2-last=Waldman |editor2-first=John R. |editor3-last=Bemis |editor3-first=William E. |date=2002 |title=An overview of Acipenseriformes |journal=Sturgeon Biodiversity and Conservation |series=Developments in Environmental Biology of Fishes |publisher=Kluwer Academic Publishers |place=Dordrecht |doi=10.1007/0-306-46854-9_4 |isbn=978-0-7923-4517-6 |volume=17 |pages=25–71 |url=http://link.springer.com/10.1007/0-306-46854-9_4 |access-date=2022-07-27 |quote=Living sturgeons and primitive paddlefishes (i.e.,polyodontids other than Polyodon) stand in sharpcontrast to all of these outgroup taxa. Their jaws are highly mobile, so that the upper jaw can be ‘projected’ far out to capture prey...|url-access=subscription }}</ref> Paddlefish, like other Acipenseriformes and several other groups of vertebrates, engage in passive [[Electroreception and electrogenesis|electroreception]] (the sensing of external [[electric field]]s) using structures called [[Ampullae of Lorenzini|ampullae]] that form an extension of the [[lateral line]] system of sensory organs. Passive electroreception (where electric fields are sensed but not generated, as in [[electric fish]]) is primarily used for detecting the weak electric fields generated by prey.<ref>{{Cite journal |last=Crampton |first=William G. R. |date=July 2019 |title=Electroreception, electrogenesis and electric signal evolution |journal=Journal of Fish Biology |language=en |volume=95 |issue=1 |pages=92–134 |doi=10.1111/jfb.13922 |pmid=30729523 |s2cid=73442571 |issn=0022-1112|doi-access=free |bibcode=2019JFBio..95...92C }}</ref> The head and rostrum of Chinese paddlefish, like those of other paddlefish, was densely packed with ampullae, indicating that enhancing electroreception was one of the rostrum's primary functions.<ref name="Grande1991" />