Editing Perch (section)

==Anatomy==
[[File:Perca fluviatilis 1879.jpg|thumb|European perch (''Perca fluviatilis''), exhibiting its green coloration and red tipped fins, as well as the vertical bars on its sides.<ref>{{Citation |last=Lydon |first=Alexander Francis |title=Perca fluviatilis |date=1879 |url=https://commons.wikimedia.org/wiki/File:Perca_fluviatilis_1879.jpg |access-date=2022-05-10}}</ref>]]
[[File:Perch head.JPG|thumb|Skull of the European Perch showing the eye sockets, connective bones, operculum, and gill slits.<ref>{{Citation |first=H |last=Cholmondeley-Pennell |title=English: Head of the European perch (Perca fluviatilis) |date=1863 |url=https://commons.wikimedia.org/wiki/File:Perch_head.JPG |access-date=2022-05-10}}</ref>]]

=== External anatomy ===
Perch have a long and round body shape which allows for fast swimming in the water. True perch have "rough" or [[ctenoid]] scales. Perch have paired [[Pectoral fin|pectoral]] and [[pelvic fin]]s, and two [[dorsal fin]]s, the first one spiny and the second soft. These two fins can be separate or joined.<ref name=":0">{{Cite journal |last=Weatherley |first=A. H. |date=1963-03-01 |title=A Note on the Head Kidney and Kidney of the Perch Perca Fluviatilis (linnaeus), with Special Reference to the Blood Vascular System |journal=Proceedings of the Zoological Society of London |language=en |volume=140 |issue=2 |pages=161–167 |doi=10.1111/j.1469-7998.1963.tb01859.x |issn=1469-7998}}</ref> The head consists of the [[skull]] (formed from loosely connected bones), [[eye]]s, [[mouth]], [[Operculum (fish)|operculum]], [[gill]]s, and a pair of [[nostril]]s (which has no connection to the oral cavity). They have small brush-like teeth across their [[jaw]]s and on the roof of their mouth. The gills are located under the operculum on both sides of the head and are used to extract oxygen molecules from water and expel carbon dioxide; the gills have [[gill raker]]s inside the mouth.<ref name=":1">{{Cite book |last=Romer |first=Alfred Sherwood |url=https://www.worldcat.org/oclc/3003870 |title=The vertebrate body |date=1977 |publisher=Saunders |others=Thomas S. Parsons |isbn=0-7216-7668-5 |edition=5th |location=Philadelphia |oclc=3003870}}</ref>

External anatomy can be used to determine the [[sex]] of perch in multiple ways. Perch have two posterior openings located on their abdomen, the [[Anus|anal]] and [[Urogenital opening|urogenital]]. In males, the shape of the urogenital opening is round and larger than the anal opening. In females, the urogenital opening is often a V- or U-shape which is a similar size to the anal opening. Also, males usually have a more brown-red colored urogenital opening compared to females.<ref>{{Cite journal |last1=Shepherd |first1= Brian S. |last2=Rees |first2=Christopher B. |last3=Sepulveda-Villet |first3=Osvaldo J. |last4=Palmquist |first4=Debra E. |last5= Binkowski |first5=Fred P. |display-authors= 3| date=May 13, 2013 |title=Identification of Gender in Yellow Perch by External Morphology: Validation in Four Geographic Strains and Effects of Estradiol |url=https://onlinelibrary.wiley.com/doi/10.1080/15222055.2013.783520 |journal= North American Journal of Aquaculture |language=en |volume=75 |issue=3 |pages=361–372 |doi=10.1080/15222055.2013.783520 |issn=1522-2055}}</ref>

=== Internal anatomy ===
The [[esophagus]] is a flexible tube that goes from the mouth to the stomach. The [[stomach]] is connected to the intestine via the [[pyloric sphincter]].<ref name=":1" /> The [[intestines]] of perch consist of the [[small intestine]] and [[large intestine]]; the intestines have many [[Pyloric caecae|pyloric caeca]] and a [[Spiral valve|spiral value]], the small intestine consists of a part called the [[duodenum]]. The [[spleen]] is located after the stomach and before the spiral value. The spleen is connected to the [[circulatory system]], not part of the [[digestive tract]]. The [[liver]] is composed of three lobes: one small lobe (includes the gall bladder) and two large lobes. Perch have long and narrow [[kidney]]s that contain clusters of [[nephron]]s which empty into the [[mesonephric duct]].<ref name=":02">{{Cite book |last1=Parker | first1=Blair | first2= Wakee | last2= McKenzie |url= https://www.worldcat.org/oclc/1132388392 |title=Origin and Evolution of Vertebrates |date=2019 |publisher=EDTECH |isbn= 978-1-83947-454-5 |oclc=1132388392}}</ref> They have a two-chambered [[heart]] consisting of four compartments: the [[Sinus venosus|sinus venous]], one [[Atrium (heart)|atrium]], one [[Ventricle (heart)|ventricle]], and [[Infundibulum (heart)|conus]].<ref name=":11">{{Cite journal |last=Randall |first=D. J. |date=1968-05-01 |title=Functional Morphology of the Heart in Fishes |journal=American Zoologist |volume=8 |issue=2 |pages=179–189 |doi=10.1093/icb/8.2.179 |pmid=5738636 |issn=0003-1569|doi-access=free }}</ref> Perch have a [[swim bladder]] that helps control [[buoyancy]] or floating within the water, the swim bladder is only found in bony fish. In perch, the duct connecting the swim bladder to the [[pharynx]] is closed so air is unable to pass through from the mouth, these fish are called [[Physoclistic|''physoclists'']]. Specifically in perch, the gas bladder can vary from 12% to 25% of [[oxygen]] and 1.4% to 2.9% of [[carbon dioxide]] gas.<ref>{{Cite book |last1= Chiasson| first1= Robert |first2= William J. | last2= Radke |url=http://worldcat.org/oclc/640832481 |title=Laboratory anatomy of the perch |date=1991 |publisher=Wm. C. Brown |oclc=640832481}}</ref> Perch [[Reproductive organs of fish|reproductive organs]] include either a pair of [[testes]] (sperm-producing) or a pair of [[Ovary|ovaries]] (egg-producing).<ref name=":02" /> [[File:Oste082p labelled.png|thumb|The above picture is a labeled image of the internal anatomy of the species Perch Perca flavescens. Each letter corresponds to an internal body part, A: gills, B: auricle of the heart, C: ventricle of the heart, D: liver, E: stomach, F: digestive cecum, G: swim bladder, H: intestine, I: testis, and J: urinary bladder.<ref>{{Citation |last=Houseman |first=Jon |title=English: Internal Anatomy of the Perch Perca flavescens. |date=2013-05-22 |url=https://commons.wikimedia.org/wiki/File:Oste082p_labelled.png |access-date=2022-05-10}}</ref>]]