Editing Northern pike (section)

===Reproduction===
Pike have a strong [[homing (biology)|homing]] behaviour;<ref name="nrcresearchpress.com"/> they inhabit certain areas by nature. During the summer, they tend to group closer to vegetation than during the winter.<ref name="Jepsen, N. 2001">{{cite journal | last1 = Jepsen | first1 = N. | last2 = Beck | first2 = S. | last3 = Skov | first3 = C. | last4 = Koed | first4 = A. | year = 2001 | title = Behavior of pike (''Esox lucius'' L.) > 50 cm in a turbid reservoir and in a clearwater lake | journal = Ecology of Freshwater Fish | volume = 10 | issue = 1 | pages = 26–34 | doi = 10.1034/j.1600-0633.2001.100104.x | bibcode = 2001EcoFF..10...26J }}</ref> The exact reason is not clear, but likely is a result of foraging or possibly reproductive needs to safeguard young. Pike [[Diel vertical migration|diel]] rhythm changes significantly over the year.<ref name="Jepsen, N. 2001"/> On sunny days, pike stay closer to the shallow shore. On windy days, they are further from shore.<ref name="Chapman, C. A 1984">{{cite journal | last1 = Chapman | first1 = C. A. | last2 = Mackay | first2 = W. C. | year = 1984 | title = Versatility in habitat use by a top aquatic predator, ''Esox lucius'' L | journal = Journal of Fish Biology | volume = 25 | issue = 1 | pages = 109–115 | doi = 10.1111/j.1095-8649.1984.tb04855.x | bibcode = 1984JFBio..25..109C }}</ref> When close to the shore, pike have a preference for shallow, vegetated areas.<ref name="Chapman, C. A 1984"/> Pike are more stationary in reservoirs than lakes.<ref name="Jepsen, N. 2001"/> A possibility is that lakes have more prey to feed upon, or possibly in reservoirs prey will ultimately cross paths with the pike. As such, this could be a form of energy conservation. Pike breed in the spring.<ref name="Reproduction, Early Life 1967 pp. 651-693"/>

Pike are physically capable of [[breeding in the wild|breeding]] at an age of about two years, [[Spawn (biology)|spawning]] in spring when the water temperature first reaches about {{convert|9|C|F}}. They have a tendency to lay a large number of eggs.<ref name="Reproduction, Early Life 1967 pp. 651-693"/> A likely explanation for such actions is to produce as many surviving offspring as possible, as many most likely die early in life. In females, the [[gonad]]s enlarge when it is time to shed her eggs.<ref name="Reproduction, Early Life 1967 pp. 651-693"/> However, after they are shed, these eggs will not hatch if the water is below {{convert|6|C|F}}.<ref name="Reproduction, Early Life 1967 pp. 651-693"/> Male pike arrive at the breeding grounds before females do, preceding them by a few weeks. In addition, the males stay after the spawning is finished.<ref name="Reproduction, Early Life 1967 pp. 651-693"/> Parental stock is vital for pike success.<ref name="Craig, J. F 1983">{{cite journal | last1 = Craig | first1 = J. F. | last2 = Kipling | first2 = C. | year = 1983 | title = Reproduction effort versus the environment; case histories of Windermere perch, ''Perca fluviatilis'' L., and pike, ''Esox lucius'' L | journal = Journal of Fish Biology | volume = 22 | issue = 6| pages = 713–727 | doi = 10.1111/j.1095-8649.1983.tb04231.x| bibcode = 1983JFBio..22..713C }}</ref> Egg survival has been shown to be positively correlated with number of eggs laid.<ref name="Craig, J. F 1983"/> For breeding, the more stable the water, the greater the fitness of the pike.<ref name="ReferenceA">{{Cite journal | doi=10.1577/1548-8659(1963)92[91:ELHOTN]2.0.CO;2| year=1963| volume=92| page=91| title=Early Life History of the Northern Pike, ''Esox lucius'' L., with Special Reference to the Factors Influencing the Numerical Strength of Year Classes| last1=Franklin| first1=Donald R.| last2=Smith| first2=Lloyd L.| journal=Transactions of the American Fisheries Society| issue=2}}</ref> Mortality results from toxic concentrations of iron or rapid temperature changes,<ref name="ReferenceA"/> and adult abundance and the strength of the resulting year classes are not related. It is based upon two points of development: one during embryo stage between fertilization and closure of the [[blastopore]], and the second between hatching and the termination of the [[alevin]] stage.<ref name="ReferenceA"/>
 
The colour of the sticky eggs is yellow to orange; the diameter is {{convert|2.5|to|3|mm|abbr=on}}. The embryos are {{convert|7.5|to|10|mm|abbr=on}} in length and able to swim after hatching, but stay on the bottom for some time. The embryonic stage is five to 16 days, dependent on water temperature (at {{convert|19|C|F}} and {{convert|10|C|F}}, respectively). Under natural circumstances, the survival from [[Fish larva|free-swimming larva]] to 75-mm pike is around 5%.{{citation needed|date=April 2016}}